WO1989010231A1 - Process for joining workpieces made of fusible material using a laser beam - Google Patents

Process for joining workpieces made of fusible material using a laser beam Download PDF

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Publication number
WO1989010231A1
WO1989010231A1 PCT/DE1989/000247 DE8900247W WO8910231A1 WO 1989010231 A1 WO1989010231 A1 WO 1989010231A1 DE 8900247 W DE8900247 W DE 8900247W WO 8910231 A1 WO8910231 A1 WO 8910231A1
Authority
WO
WIPO (PCT)
Prior art keywords
workpieces
laser radiation
energy
joining
joint
Prior art date
Application number
PCT/DE1989/000247
Other languages
German (de)
French (fr)
Inventor
Reinhart Poprawe
Rolf Klein
Original Assignee
Fraunhofer-Gesellschaft Zur Förderung Der Angewand
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fraunhofer-Gesellschaft Zur Förderung Der Angewand filed Critical Fraunhofer-Gesellschaft Zur Förderung Der Angewand
Publication of WO1989010231A1 publication Critical patent/WO1989010231A1/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/90—Measuring or controlling the joining process
    • B29C66/91—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux
    • B29C66/912—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by measuring the temperature, the heat or the thermal flux
    • B29C66/9121—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by measuring the temperature, the heat or the thermal flux by measuring the temperature
    • B29C66/91211—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by measuring the temperature, the heat or the thermal flux by measuring the temperature with special temperature measurement means or methods
    • B29C66/91216—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by measuring the temperature, the heat or the thermal flux by measuring the temperature with special temperature measurement means or methods enabling contactless temperature measurements, e.g. using a pyrometer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/08—Devices involving relative movement between laser beam and workpiece
    • B23K26/083—Devices involving movement of the workpiece in at least one axial direction
    • B23K26/0838—Devices involving movement of the workpiece in at least one axial direction by using an endless conveyor belt
    • B23K26/0846—Devices involving movement of the workpiece in at least one axial direction by using an endless conveyor belt for moving elongated workpieces longitudinally, e.g. wire or strip material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/14—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation
    • B29C65/16—Laser beams
    • B29C65/1629—Laser beams characterised by the way of heating the interface
    • B29C65/1632—Laser beams characterised by the way of heating the interface direct heating the surfaces to be joined
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/14—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation
    • B29C65/16—Laser beams
    • B29C65/1629—Laser beams characterised by the way of heating the interface
    • B29C65/1635—Laser beams characterised by the way of heating the interface at least passing through one of the parts to be joined, i.e. laser transmission welding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/14—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation
    • B29C65/16—Laser beams
    • B29C65/1629—Laser beams characterised by the way of heating the interface
    • B29C65/1635—Laser beams characterised by the way of heating the interface at least passing through one of the parts to be joined, i.e. laser transmission welding
    • B29C65/1641—Laser beams characterised by the way of heating the interface at least passing through one of the parts to be joined, i.e. laser transmission welding making use of a reflector on the opposite side, e.g. a polished mandrel or a mirror
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/14—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation
    • B29C65/16—Laser beams
    • B29C65/1629—Laser beams characterised by the way of heating the interface
    • B29C65/1654—Laser beams characterised by the way of heating the interface scanning at least one of the parts to be joined
    • B29C65/1658—Laser beams characterised by the way of heating the interface scanning at least one of the parts to be joined scanning once, e.g. contour laser welding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/11—Joint cross-sections comprising a single joint-segment, i.e. one of the parts to be joined comprising a single joint-segment in the joint cross-section
    • B29C66/112—Single lapped joints
    • B29C66/1122—Single lap to lap joints, i.e. overlap joints
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/11—Joint cross-sections comprising a single joint-segment, i.e. one of the parts to be joined comprising a single joint-segment in the joint cross-section
    • B29C66/114—Single butt joints
    • B29C66/1142—Single butt to butt joints
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/11—Joint cross-sections comprising a single joint-segment, i.e. one of the parts to be joined comprising a single joint-segment in the joint cross-section
    • B29C66/116—Single bevelled joints, i.e. one of the parts to be joined being bevelled in the joint area
    • B29C66/1162—Single bevel to bevel joints, e.g. mitre joints
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/12—Joint cross-sections combining only two joint-segments; Tongue and groove joints; Tenon and mortise joints; Stepped joint cross-sections
    • B29C66/122—Joint cross-sections combining only two joint-segments, i.e. one of the parts to be joined comprising only two joint-segments in the joint cross-section
    • B29C66/1226—Joint cross-sections combining only two joint-segments, i.e. one of the parts to be joined comprising only two joint-segments in the joint cross-section comprising at least one bevelled joint-segment
    • B29C66/12261—Joint cross-sections combining only two joint-segments, i.e. one of the parts to be joined comprising only two joint-segments in the joint cross-section comprising at least one bevelled joint-segment the two joint-segments being bevelled, e.g. the two joint-segments forming a V
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/12—Joint cross-sections combining only two joint-segments; Tongue and groove joints; Tenon and mortise joints; Stepped joint cross-sections
    • B29C66/124—Tongue and groove joints
    • B29C66/1244—Tongue and groove joints characterised by the male part, i.e. the part comprising the tongue
    • B29C66/12443—Tongue and groove joints characterised by the male part, i.e. the part comprising the tongue having the tongue substantially in the middle
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/12—Joint cross-sections combining only two joint-segments; Tongue and groove joints; Tenon and mortise joints; Stepped joint cross-sections
    • B29C66/124—Tongue and groove joints
    • B29C66/1246—Tongue and groove joints characterised by the female part, i.e. the part comprising the groove
    • B29C66/12463—Tongue and groove joints characterised by the female part, i.e. the part comprising the groove being tapered
    • B29C66/12464—Tongue and groove joints characterised by the female part, i.e. the part comprising the groove being tapered being V-shaped
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/12—Joint cross-sections combining only two joint-segments; Tongue and groove joints; Tenon and mortise joints; Stepped joint cross-sections
    • B29C66/124—Tongue and groove joints
    • B29C66/1248—Interpenetrating groove joints
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/12—Joint cross-sections combining only two joint-segments; Tongue and groove joints; Tenon and mortise joints; Stepped joint cross-sections
    • B29C66/128—Stepped joint cross-sections
    • B29C66/1282—Stepped joint cross-sections comprising at least one overlap joint-segment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/12—Joint cross-sections combining only two joint-segments; Tongue and groove joints; Tenon and mortise joints; Stepped joint cross-sections
    • B29C66/128—Stepped joint cross-sections
    • B29C66/1282—Stepped joint cross-sections comprising at least one overlap joint-segment
    • B29C66/12821—Stepped joint cross-sections comprising at least one overlap joint-segment comprising at least two overlap joint-segments
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/12—Joint cross-sections combining only two joint-segments; Tongue and groove joints; Tenon and mortise joints; Stepped joint cross-sections
    • B29C66/128—Stepped joint cross-sections
    • B29C66/1284—Stepped joint cross-sections comprising at least one butt joint-segment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/12—Joint cross-sections combining only two joint-segments; Tongue and groove joints; Tenon and mortise joints; Stepped joint cross-sections
    • B29C66/128—Stepped joint cross-sections
    • B29C66/1284—Stepped joint cross-sections comprising at least one butt joint-segment
    • B29C66/12841—Stepped joint cross-sections comprising at least one butt joint-segment comprising at least two butt joint-segments
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/13—Single flanged joints; Fin-type joints; Single hem joints; Edge joints; Interpenetrating fingered joints; Other specific particular designs of joint cross-sections not provided for in groups B29C66/11 - B29C66/12
    • B29C66/133—Fin-type joints, the parts to be joined being flexible
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/14—Particular design of joint configurations particular design of the joint cross-sections the joint having the same thickness as the thickness of the parts to be joined
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/40—General aspects of joining substantially flat articles, e.g. plates, sheets or web-like materials; Making flat seams in tubular or hollow articles; Joining single elements to substantially flat surfaces
    • B29C66/41—Joining substantially flat articles ; Making flat seams in tubular or hollow articles
    • B29C66/43—Joining a relatively small portion of the surface of said articles
    • B29C66/432—Joining a relatively small portion of the surface of said articles for making tubular articles or closed loops, e.g. by joining several sheets ; for making hollow articles or hollow preforms
    • B29C66/4322—Joining a relatively small portion of the surface of said articles for making tubular articles or closed loops, e.g. by joining several sheets ; for making hollow articles or hollow preforms by joining a single sheet to itself
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/72—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the structure of the material of the parts to be joined
    • B29C66/723—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the structure of the material of the parts to be joined being multi-layered
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/73—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset
    • B29C66/739—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of the parts to be joined being a thermoplastic or a thermoset
    • B29C66/7392—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of at least one of the parts being a thermoplastic
    • B29C66/73921—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of at least one of the parts being a thermoplastic characterised by the materials of both parts being thermoplastics
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/83—General aspects of machine operations or constructions and parts thereof characterised by the movement of the joining or pressing tools
    • B29C66/836—Moving relative to and tangentially to the parts to be joined, e.g. transversely to the displacement of the parts to be joined, e.g. using a X-Y table
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/84—Specific machine types or machines suitable for specific applications
    • B29C66/849—Packaging machines
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/90—Measuring or controlling the joining process
    • B29C66/91—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux
    • B29C66/912—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by measuring the temperature, the heat or the thermal flux
    • B29C66/9121—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by measuring the temperature, the heat or the thermal flux by measuring the temperature
    • B29C66/91221—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by measuring the temperature, the heat or the thermal flux by measuring the temperature of the parts to be joined
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/90—Measuring or controlling the joining process
    • B29C66/91—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux
    • B29C66/914—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux
    • B29C66/9141—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the temperature
    • B29C66/91411—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the temperature of the parts to be joined, e.g. the joining process taking the temperature of the parts to be joined into account
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/90—Measuring or controlling the joining process
    • B29C66/91—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux
    • B29C66/914—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux
    • B29C66/9161—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the heat or the thermal flux, i.e. the heat flux
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C53/00—Shaping by bending, folding, twisting, straightening or flattening; Apparatus therefor
    • B29C53/36—Bending and joining, e.g. for making hollow articles
    • B29C53/38—Bending and joining, e.g. for making hollow articles by bending sheets or strips at right angles to the longitudinal axis of the article being formed and joining the edges
    • B29C53/48—Bending and joining, e.g. for making hollow articles by bending sheets or strips at right angles to the longitudinal axis of the article being formed and joining the edges for articles of indefinite length, i.e. bending a strip progressively
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/72—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the structure of the material of the parts to be joined
    • B29C66/723—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the structure of the material of the parts to be joined being multi-layered
    • B29C66/7232—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the structure of the material of the parts to be joined being multi-layered comprising a non-plastics layer
    • B29C66/72321—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the structure of the material of the parts to be joined being multi-layered comprising a non-plastics layer consisting of metals or their alloys
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/81—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps
    • B29C66/812—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the composition, by the structure, by the intensive physical properties or by the optical properties of the material constituting the pressing elements, e.g. constituting the welding jaws or clamps
    • B29C66/8126—General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the composition, by the structure, by the intensive physical properties or by the optical properties of the material constituting the pressing elements, e.g. constituting the welding jaws or clamps characterised by the intensive physical properties or by the optical properties of the material constituting the pressing elements, e.g. constituting the welding jaws or clamps
    • B29C66/81266—Optical properties, e.g. transparency, reflectivity
    • B29C66/81268—Reflective to electromagnetic radiation, e.g. to visible light
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/90—Measuring or controlling the joining process
    • B29C66/96—Measuring or controlling the joining process characterised by the method for implementing the controlling of the joining process
    • B29C66/961—Measuring or controlling the joining process characterised by the method for implementing the controlling of the joining process involving a feedback loop mechanism, e.g. comparison with a desired value
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2711/00—Use of natural products or their composites, not provided for in groups B29K2601/00 - B29K2709/00, for preformed parts, e.g. for inserts
    • B29K2711/12—Paper, e.g. cardboard
    • B29K2711/123—Coated
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2023/00—Tubular articles
    • B29L2023/22—Tubes or pipes, i.e. rigid
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00—Other particular articles
    • B29L2031/712—Containers; Packaging elements or accessories, Packages
    • B29L2031/7128—Bags, sacks, sachets

Definitions

  • the invention relates to a method for joining workpieces made of fusible material with laser radiation, which is directed at a joint of the workpieces, in particular made of thermoplastic plastic, and is applied with an energy density, which fuses and flows into one another in the region of the joint by energy absorption causes.
  • Metallic workpieces are welded using laser radiation by melting the workpiece surface in the area of the joint.
  • the energy coupled into the workpiece for melting is transported to greater depths by thermal conduction.
  • thermal conduction In the case of workpieces with low heat conduction, for example made of ceramic or plastic, there is a risk of melting the workpiece surface Damage to the material due to overheating and the heat conduction is low, so that conventional welding with laser radiation leads to unsatisfactory results.
  • seal welding for e.g. Thermoplastic plastics are seal welding, hot gas welding, vibration welding and ultrasonic welding.
  • seal welding and hot gas welding the material is melted via heat conduction after the necessary energy has been coupled in via the workpiece surface.
  • the processing speed is limited by the low thermal conductivity of the material.
  • Seal welding, vibration welding and ultrasonic welding are tool-dependent joining processes, because the energy required to weld the workpieces must be transferred by tools that are specially manufactured for the joining and workpiece geometry. These procedures are therefore not very adaptable.
  • thermoplastic foils From DE-OS 25 44 371 a method for welding thermoplastic foils is known, in which laser light is radiated into superimposed foil layers and thereby partially absorbed. Part of the laser energy radiated through the film hits a base part, which reflects the energy back. When it hits this base part, it is heated, so that it must be designed to withstand the thermal stress.
  • the retroreflection of energy by a heated backing part is obviously disadvantageous because the heating of the backing part loses energy and because the process speed has to be reduced considerably because of the required heating of the backing part.
  • the invention is based on the object to improve a method of the type mentioned at the outset so that the entire radiation energy provided is available for melting material in the area of the joint.
  • This object is achieved in that the workpiece irradiation in the sense of complete energy absorption is carried out exclusively by the material volume of the workpieces.
  • the entire energy of the laser radiation is made available for melting within the material of the workpieces.
  • energy loss can be virtually completely ruled out, so that it is possible to work with lasers of low power which are correspondingly inexpensive, or so that a higher processing speed is made possible.
  • the elimination of heat conduction processes when coupling the laser energy into the workpieces also fundamentally enables the processing speed to be increased.
  • additives are fillers, dyes, plasticizers, etc. They are selected with a view to the fact that laser radiation of a certain wavelength is more or less absorbed.
  • the addition of the additive can be carried out in such a way that the penetration depth of the laser radiation into the material is also influenced, as a result of which the melting depth can be influenced. It is therefore possible, for example, to provide a film on one side with a layer in which the laser radiation is completely absorbed, so that, accordingly, only this layer melts. To melt the entire layer, the layer thickness must correspond to the laser energy supplied per unit of time be coordinated.
  • One possibility for such a coordination is to influence the energy absorption in the material by selecting the wavelength of the laser radiation.
  • other methods known per se can also be used, for example influencing the energy absorption in the material by changing the processing speed.
  • the regulation advantageously takes place in Dependence on the continuously measured melt temperature.
  • a non-contact temperature measurement is used in the area of the joining zone, e.g. with a thermopile or with a pyrometer. The control is carried out according to the measurement result in such a way that the decomposition temperature of the material is not reached or exceeded.
  • an energy-reflecting part is used behind the energy-absorbing material volume in the direction of irradiation, and at least one part reflecting the laser radiation is used.
  • a reflection of the laser radiation means that the part causing the reflection itself does not absorb any energy, apart from immaterial parts which are insignificant for the energy balance.
  • the reflected laser radiation can then be completely absorbed in the material. If the reflected radiation is too high in energy to be absorbed in the reflection region of the material, a further part reflecting the laser radiation can be used if the beam guidance required for this second reflection or for further reflections is determined in a suitable manner.
  • the method is not restricted to the part reflecting the laser radiation being behind the part to be joined Workpieces is arranged. It is also advantageously designed such that a part reflecting laser radiation is used in the interior of at least one workpiece or between the two workpieces. This makes it possible to determine the penetration depth of the laser radiation, in particular in the case of thick workpieces, for example in the case of foils, plates or semi-finished products. Such a method is used, for example, in cavity welding, where it is important that the wall surface facing away from the laser beam is not melted.
  • the method is carried out so that the laser radiation at a beam of the energy-absorbing material volume is irradiated onto an area that limits the energy-absorbing material volume at an angle below the total reflection angle.
  • the surface of the work pot volume which is absorbable can be formed by a previously mentioned part which reflects laser radiation.
  • total reflection is also possible at other interfaces, for example at the interface of the workpiece with the air. If suitable interfaces are present as a result of the corresponding design of the arrangement serving the method, the total reflection means that the laser radiation can no longer leave the material or the workpiece and the radiation energy is consequently completely absorbed by the volume of the material.
  • the laser radiation is irradiated perpendicular or parallel to the joining plane of the work pieces in their energy absorbing material volume.
  • the most favorable direction of irradiation is determined by the given joining geometry, as well as by the desired goal.
  • the same purpose of better melt mixing is served by a method in which laser radiation is used in a cross-section which leads to preheating regions of the workpieces fed to the joining zone with mutual approximation.
  • a further possibility for promoting the connection strength of workpieces is that the workpieces are used with mutual connections which promote the mutual mixing of the melted material.
  • Such a design of the workpieces with connection interventions is particularly suitable for thicker workpieces, such as plates or semi-finished products.
  • the specially designed joining surfaces of the workpieces to be connected do not need to be carried out precisely, since any tolerances or distances between the workpieces disappear when the material is melted.
  • the shape of the workpieces therefore means no great manufacturing effort.
  • Composite foils are advantageously used as workpieces which have at least one thermoplastic have as a joining layer and / or have a composite layer reflecting a laser radiation.
  • a thermoplastic layer as a joining layer.
  • Such a composite film can therefore have a layer which is suitable but not weldable for a specific application and which is provided with a layer which is not suitable for the specific application but serves for joining.
  • the composite film can instead or at the same time have a composite layer which reflects the laser radiation in order to ensure that the entire radiation energy is used to melt the layer serving for joining.
  • Such a radiation-reflecting layer is either an insert layer covered on both sides, or it is open on one side, wherein the radiation-reflecting composite layer can also serve as a layer with a further special purpose, for example thermal shielding or hygienic storage of food.
  • the invention also relates to a device for joining workpieces made of meltable material with laser radiation, in particular for thermoplastic plastic films or the like, which is aimed at a joint of the workpieces and has an energy density which allows material to melt and flow into one another Joining caused by energy absorption.
  • a device for joining workpieces made of meltable material with laser radiation in particular for thermoplastic plastic films or the like, which is aimed at a joint of the workpieces and has an energy density which allows material to melt and flow into one another Joining caused by energy absorption.
  • the Guides are reflective of laser radiation.
  • the workpieces can be brought into a shape that is useful for joining, and at the same time the guide bodies are designed in such a way that energy losses cannot occur because the laser radiation is reflected by them in the joint gap or in the flexible workpieces to be connected to one another, where it serves to melt the material.
  • it has polished guide surfaces for processing thermoplastic plastic films, the guide surfaces not only serving for radiation reflection, but also for the surface-protecting feeding of the plastic films.
  • the device is particularly optimal for connecting plastic films if it has a laser beam supplied parallel to the joining plane of the thermoplastic films and if the width and / or the length of the beam spot on the films can be adjusted.
  • the films can be preheated in the desired sense by a suitable width of the beam spot, namely with the lower energy density in the edge area of the laser beam, while the area of the area formed by the overlapping of films is determined by the choice of the length of the beam spot is being melted.
  • FIGS. 5a to 1 joining gaps or joining zones of mutually: workpieces of larger material thicknesses to be connected.
  • a tubular bag 2 is to be produced from a thermoplastic workpiece 1 in the form of a flat plastic film, which has a seam 3.
  • a film guiding device 5 is required, which essentially consists of the shaped shoulder 6 shown, which has a run-up surface 6 'for the workpiece 1.
  • the ramp surface 6 ' merges into a shoulder region 6' ', from which the workpiece 1 with the edges 1', 1 '' is tangentially brought together by a guide body 7 of the shaped shoulder 6 in order to form the joint or joint 3 .
  • the connection of the joining seam 3 or the edges 1 ′, 1 ′′ of the workpiece 1 to the joining seam 3 is achieved by suitable beam guidance and beam shaping of the laser beam 4.
  • the mirror 11 serves to reflect the laser beam 4 while simultaneously deflecting and focusing on the joint 12 marked by a circle between the edges of the guide body 7.
  • the focusing takes place, for example, in such a way that the laser beam at the joint 12 has a beam spot with one in the direction of the joint gap compared to the beam width has considerable length in order to achieve a secure joining of the edges 1 ', 1''.
  • the guide body 7 is reflective of laser radiation because it is highly polished or mirrored on the surface. It reflects the radiation transmitted through the workpiece 1 back into the absorbing material, and depending on the type of material, multiple reflection between the opposite surfaces of the guide body 7 is also possible, if these are designed for this, for example long enough.
  • FIG. 2 The principle of the effect of laser radiation transmitted through a workpiece for energy absorption is explained with reference to FIG. 2.
  • the diagram shows the ratio l / l o of a laser light beam radiated in the direction 13 onto a workpiece 14 and its course as a function of the irradiated thickness of the latter. It can be seen that the luminous flux decreases progressively until it leaves the workpiece 14 on the exit side 15. It then strikes a reflector 16, which is reflecting laser radiation, so that the luminous flux of the remaining strength enters the workpiece 14 again. It is absorbed there in accordance with the dashed curve, so that there is complete luminous flux or energy absorption in the workpiece 14.
  • the absorption of the reflected laser radiation means a corresponding increase in heat in the workpiece 14 corresponding to the dashed area 17
  • the reflected radiation or luminous flux Itrans thus leads to a correspondingly uniform distribution of the energy in the workpiece 14 and thus to an equalization of the joining strength. This is a further significant advantage of the method according to the invention in addition to reducing the energy losses or increasing the processing speed.
  • FIG. 3 shows the connection of two workpieces 1 designed as foils, which are brought together tangentially in their feed directions 18 by guide bodies 7 and by a laser beam 4 incident in the direction of irradiation 19 be connected to a thick sheet 20 which is withdrawn in the feed direction 21.
  • the laser beam 4 is focused in such a way that it has a beam spot width 22 which exceeds the thickness of the thick film 20 to be produced.
  • the foil works 1 are heated or melted in regions 23 before they converge in order to be connected to one another in the joining zone 24. If such an early heating is not to take place, then the laser beam 4 need only have a beam spot width 22 ′ which is based on the spacing of the guide bodies 7 in the region of the joining zone 24.
  • the foil works 1 are irradiated with a beam spot width 22 and partially let the laser radiation pass through, this strikes reflection surfaces 25, from which it is reflected in the material, which is indicated by the arrows 26.
  • the relevant reflection surfaces 25 are in turn highly polished or surface mirrored, although this is not necessary if the apparent reflection angle is smaller than the angle of total reflection on the outer surface 27 of the workpieces 1.
  • FIG. 4 shows an arrangement similar to FIG. 3 with workpieces 1 which consist of composite film.
  • Each workpiece 1 has an outer layer 28, a joining layer 29, which thus serve to join both workpieces 1 to form a thick film 20 ', and an aluminum layer 30 embedded by the layers 28, 29, which serves to reflect portions of the laser beam 4 which form the joining layer 29 shine through.
  • the guide bodies 7 have radiation-reflecting properties, or that due to the arrangement of the workpieces 1 on the one hand and the dimensioning or focusing of the laser beam 4 on the other hand, any total reflection on the middle layer is taken into account.
  • 5a to 5i show different designs of joining gaps or joining zones in the case of workpieces of greater thickness.
  • 5a shows a butt joint of two plate-shaped workpieces 31 with a joining gap 32 vertical to them and a joining zone 33, the width of which is determined by the width 22 of the beam spot of the laser beam 4.
  • the joining gap 32 is arranged obliquely in the joining zone 33 in such a way that it extends over its entire width.
  • 5c shows two plate-shaped workpieces 31 with an overlap joint in which the overlap area is arranged in the plate center plane.
  • the joint according to FIG. 5 d is simply wedge-shaped, with all surface sections of a workpiece 31 lying within the joining zone 33.
  • the workpieces 31 are tongue and groove-like and, according to FIG. 5f, double wedge-shaped or toothed.
  • connection strength of the workpieces 31 is achieved by better mixing of the melts.
  • 5g, h show a simple overlap joint or an overlap joint formed by the depositing of workpieces 31, the joining zone 33 in each case corresponding to the overlap width.
  • FIG. 5i shows a flange connection of two workpieces 31 * designed as semifinished products, in which the adjoining surfaces have a double wedge-shaped cross section, for example according to FIG. 5f, but the width 22 of the beam spot of the laser beam 4 is equal to the total width of the connecting flange.
  • the mixing of the molten material is better, the deeper the mutual engagement of the workpieces 31, 31 ', and the greater the proportion of the connecting surfaces inclined to the workpiece plane.
  • 5k, 1 show plate-like workpieces 31 in a butt-jointed arrangement and with a large number of connection interventions or with a corresponding meandering joining gap 32 which extends over the entire width of the joining zone 33.
  • a special feature is the arrangement of a Re flektorstsammlungs 34, which prevents the laser radiation radiated in the direction 35 completely penetrates the workpieces 31. Rather, the laser radiation is reflected, thereby determining the depth of the joining zone 33.
  • the two embodiments differ in that the reflecting part 34 in FIG. 5k is arranged in the joining gap 32 between the workpieces 31, for which purpose the joining gap 32 must be of correspondingly enlarged cross-section. 51, the reflecting part 34 is arranged inside the left workpiece 31 in a correspondingly shaped groove.
  • the above-described methods are carried out, for example, with a laser beam from a carbon dioxide laser, it being possible for the beam guidance to be adapted to the application.
  • the beam guidance can be controlled three-dimensionally, so that the method is very adaptable when compared with the conventional joining methods.
  • the method can be used with particular advantage in the case of thin films of 10 micrometers to 1 millimeter, because with such material thicknesses the plastics often transmit radiation which would otherwise be lost.
  • the method according to the invention is used for joining workpieces made of meltable material with laser radiation.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Electromagnetism (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Thermal Sciences (AREA)
  • Plasma & Fusion (AREA)
  • Lining Or Joining Of Plastics Or The Like (AREA)
  • Laser Beam Processing (AREA)

Abstract

In a process for joining workpieces (1) made of fusible material, in particular a thermoplastic material, a laser beam (19) is directed onto the site of the joint (24) between the worpieces, the energy density of the beam being such as to ensure fusion and intimate mixing of the material in the region of the joint due to absorption of energy. To ensure that all the available radiant energy is used to melt the material in the region of the joint (24), the workpiece is irradiated so as to ensure that all the energy is absorbed, exclusively through the volumes of the material of the workpieces.

Description

Verfahren zum Fügen von Werkstücken aus aufschmelzbarem Werkstoff mit Laserstrahlung Process for joining workpieces made of meltable material with laser radiation
Beschreibungdescription
Technisches GebietTechnical field
Die Erfindung bezieht sich auf ein Verfahren zum Fügen von Werkstücken aus aufschmelzbar em Werkstoff mit Laserstrahlung, die auf eine Fügestelle der insbesondere aus thermoplastischem Kunststoff bestehenden Werkstücke gerichtet und mit einer Energiedichte angewendet wird, die ein Aufschmelzen und Ineinanderfließen von Werkstoff im Bereich der Fügestelle durch Energieabsorption bewirkt.The invention relates to a method for joining workpieces made of fusible material with laser radiation, which is directed at a joint of the workpieces, in particular made of thermoplastic plastic, and is applied with an energy density, which fuses and flows into one another in the region of the joint by energy absorption causes.
Stand der TechnikState of the art
Das Schweißen metallischer Werkstücke mit Lasers trahlung erfolgt durch Aufschmelzen der Werks tückoberflache im Bereich der Fügestelle. Dabei wird die zum Aufschmelzen in das Werkstück eingekoppelte Energie durch Wärmeleitung in größere Tiefen transportiert. Bei Werkstücken mit geringer Wärmeleitung, beispielsweise aus Keramik oder Kunststoff, ist ein Aufschmelzen der Werkstückoberfläche mit der Gefahr einer Schädigung des Werkstoffs durch überhitzung verbunden und die Wärmeleitung ist gering, so daß ein herkömmliches Schweißen mit Laserstrahlung zu unbefriedigenden Ergebnissen führt.Metallic workpieces are welded using laser radiation by melting the workpiece surface in the area of the joint. The energy coupled into the workpiece for melting is transported to greater depths by thermal conduction. In the case of workpieces with low heat conduction, for example made of ceramic or plastic, there is a risk of melting the workpiece surface Damage to the material due to overheating and the heat conduction is low, so that conventional welding with laser radiation leads to unsatisfactory results.
Konventionelle Schweißverfahren für z.B. thermoplastisch Kunststoffe sind Siegelschweißen, Warmgasschweißen, Vibrationsschweißen und Ultraschallschweißen. Beim Siegelschweißen und beim Warmgasschweißen erfolgt das Aufschmelzen des Werkstoffs über Wärmeleitung, nachdem die nötige Energie über die Werkstückoberfläche eingekoppelt wurde. Die Bearbeitungsgeschwindigkeit wird jedoch durch die gerine Wärmeleitfähigkeit des Werkstoffs begrenzt. Siegelschweißen, Vibrationsschweißen und Ultraschallschweißen sind werkzeugabhängige Fügeverfahren, weil die zum Verschweißen der Werkstücke nötige Energie durch speziell für die Füge- und Werkstückgeometrie herzustellende Werkzeuge übertragen werden muß. Diese Verfahren sind daher nicht sehr anpassungsfähig.Conventional welding processes for e.g. Thermoplastic plastics are seal welding, hot gas welding, vibration welding and ultrasonic welding. In seal welding and hot gas welding, the material is melted via heat conduction after the necessary energy has been coupled in via the workpiece surface. However, the processing speed is limited by the low thermal conductivity of the material. Seal welding, vibration welding and ultrasonic welding are tool-dependent joining processes, because the energy required to weld the workpieces must be transferred by tools that are specially manufactured for the joining and workpiece geometry. These procedures are therefore not very adaptable.
Aus der DE-OS 25 44 371 ist ein Verfahren zum Verschweiß von thermoplastischen Folien bekannt, bei dem Laserlicht in übereinandergelegte Folienschichten eingestrahlt und dabei zum Teil absorbiert wird. Bin Teil der durch die Folie hindurchg strahlten Laserenergie trifft auf ein Unterlagsteil, das die Energie zurückstrahlt. Beim Auftreffen auf dieses Unterlagsteil wird dieses erwärmt, so daß es entsprechend beschaffen sein muß, um der Wärmebeanspruchung zu widerstehen. Das Zurückstrahlen von Energie durch ein erwärmtes Unterlagsteil ist offensichtlich nachteilig, weil durch die Erwärmung des Unterlagsteils Energie verlorengeht, und weil die Prozeßgeschwindigkeit wegen der erforderlichen Erwärmung des Unterlagsteils erheblich herabgesetzt werden muß.From DE-OS 25 44 371 a method for welding thermoplastic foils is known, in which laser light is radiated into superimposed foil layers and thereby partially absorbed. Part of the laser energy radiated through the film hits a base part, which reflects the energy back. When it hits this base part, it is heated, so that it must be designed to withstand the thermal stress. The retroreflection of energy by a heated backing part is obviously disadvantageous because the heating of the backing part loses energy and because the process speed has to be reduced considerably because of the required heating of the backing part.
Darstellung der ErfindungPresentation of the invention
Demgegenüber liegt der Erfindung die Aufgabe zugrunde, ein Verfahren der eingangs genannten Art so zu verbessern, daß die gesamte zur Verfügung gestellte Strahlungsenergie zum Aufschmelzen von Werkstoff im Bereich der Fügestelle zur Verfügung steht.In contrast, the invention is based on the object to improve a method of the type mentioned at the outset so that the entire radiation energy provided is available for melting material in the area of the joint.
Diese Aufgabe wird dadurch gelöst, daß die Werkstückbestrahlung im Sinne vollständiger Energieabsorption ausschließlich durch Werkstoffvolumen der Werkstücke durchgeführ wird.This object is achieved in that the workpiece irradiation in the sense of complete energy absorption is carried out exclusively by the material volume of the workpieces.
Für die Erfindung ist von Bedeutung, daß die gesamte Energie der Laserstrahlung innerhalb des Werkstoffs der Werkstücke zum Aufschmelzen zur Verfügung gestellt wird. Dadurch kann Energieverlust praktisch vollständig ausgeschlossen werden, so daß mit Lasern kleiner Leistung gearbeitet werden kann, die entsprechend preiswert sind, bzw. so daß eine größere Bearbeitungsgeschwindigkeit ermöglicht wird. Die Ausschaltung von Wärmeleitungsvorgängen beim Einkoppeln der Laserenergie in die Werkstücke ermöglicht ebenfalls grundsätzlich eine Steigerung der Bearbeitungsgeschwindigkeit.It is important for the invention that the entire energy of the laser radiation is made available for melting within the material of the workpieces. As a result, energy loss can be virtually completely ruled out, so that it is possible to work with lasers of low power which are correspondingly inexpensive, or so that a higher processing speed is made possible. The elimination of heat conduction processes when coupling the laser energy into the workpieces also fundamentally enables the processing speed to be increased.
Vorteilhaft ist es, das Energieabsorptionsvermögen des Werkstoffs mit Zusatzstoffen zu beeinflussen, die dem Werkstoff bei dessen Herstellung beigegeben werden. Solche Zusatzstoffe sind Füllstoffe, Farbstoffe, Weichmacher usw. Sie werden im Hinblick darauf ausgewählt, daß LaserStrahlung bestimmter Wellenlänge mehr oder weniger absorbiert wird. Dabei kann die Beigabe der Zusatzstof f e so erfolgen, daß damit auch die Eindringtiefe der Laserstrahlung in den Werkstoff beeinflußt wird, wodurch die Aufschmelztiefe beeinflußbar ist. Es ist also z.B. möglich, eine Folie auf einer Seite mit einer Schicht zu versehen, in der die Laserstrahlung vollständig absorbiert wird, so daß dementsprechend auch nur diese Schicht aufschmilzt. Zum Aufschmelzen der gesamten Schicht muß die Schichtdicke auf die pro Zeiteinheit zugeführte Laserenergie abgestimmt werden. Eine Möglichkeit für eine solche Abstimmung ist es', die Energieabsorption im Werkstoff durch eine Auswahl der Wellenlänge der Laserstrahlung zu beeinflussen. Es versteht sich jedoch, daß auch andere, an sich bekannte Verfahren verwendet werden können, beispielsweise die Beeinflussung der Energieabsorption im Werkstoff durch Veränderung der Bearbeitungsgeschwindigkeit .It is advantageous to influence the energy absorption capacity of the material with additives that are added to the material during its manufacture. Such additives are fillers, dyes, plasticizers, etc. They are selected with a view to the fact that laser radiation of a certain wavelength is more or less absorbed. The addition of the additive can be carried out in such a way that the penetration depth of the laser radiation into the material is also influenced, as a result of which the melting depth can be influenced. It is therefore possible, for example, to provide a film on one side with a layer in which the laser radiation is completely absorbed, so that, accordingly, only this layer melts. To melt the entire layer, the layer thickness must correspond to the laser energy supplied per unit of time be coordinated. One possibility for such a coordination is to influence the energy absorption in the material by selecting the wavelength of the laser radiation. However, it goes without saying that other methods known per se can also be used, for example influencing the energy absorption in the material by changing the processing speed.
Wird so verfahren, daß Prozeßparamter geregelt werden, daß also die Bearbeitungsgeschwindigkeit und/oder die Leistung fortwährend geregelt werden, um die Energieabsorption im Werk- stoffvolumen zu beeinflussen, also im Sinne einer vollständigen Energieabsorption ausschließlich durch Werkstoffvolumen der Werkstücke, so erfolgt die Regelung vorteilhafterweise in Abhängigkeit von der fortwährend gemessenen Schmelzentemperatur. Dabei wird eine berührungslose Temperaturmessung im Bereich der Fügezone benutzt, z.B. mit einer Thermosäule oder mit einem Pyrometer. Die Regelung erfolgt dem Meßergebnis entsprechend derart, daß die Zersetzungstemperatur des Werkstoffs nicht erreicht oder überschritten wird. Des weiteren ist von besonderer Bedeutung, und zwar bei einem Verfahren, bei dem in Bestrahlungsrichtung hinter dem energieabsorbierenden Werkstoffvolumen ein energierückstrahlendes Teil verwendet wird, das mindestens ein die Laserstrahlung reflektierendes Teil verwendet wird. Eine Reflexion der Laserstrahlung bedeutet, daß das die Reflexion bewirkende Teil selbst keine Energie aufnimmt, abgesehen von unmaßgeblichen, für die Energiebilanz unwesentlichen Anteilen. Die reflektierte Laserstrahlung kann dann im Werkstoff vollständig absorbiert werden. Ist die reflektierte Strahlung zu energiereich, um im Reflexionsbereich des Werkstoffs absorbiert zu werden, so kann ein weiteres die Laserstrahlung reflektierendes Teil verwendet werden, wenn die für diese zweite Reflexion oder für weitere Reflexionen erforderliche Strahlführung in geeigneter Weise festgelegt wird.If you proceed in such a way that process parameters are regulated, that is to say the processing speed and / or the output are regulated continuously in order to influence the energy absorption in the material volume, that is to say in the sense of complete energy absorption exclusively by the material volume of the workpieces, the regulation advantageously takes place in Dependence on the continuously measured melt temperature. A non-contact temperature measurement is used in the area of the joining zone, e.g. with a thermopile or with a pyrometer. The control is carried out according to the measurement result in such a way that the decomposition temperature of the material is not reached or exceeded. Furthermore, it is of particular importance in a method in which an energy-reflecting part is used behind the energy-absorbing material volume in the direction of irradiation, and at least one part reflecting the laser radiation is used. A reflection of the laser radiation means that the part causing the reflection itself does not absorb any energy, apart from immaterial parts which are insignificant for the energy balance. The reflected laser radiation can then be completely absorbed in the material. If the reflected radiation is too high in energy to be absorbed in the reflection region of the material, a further part reflecting the laser radiation can be used if the beam guidance required for this second reflection or for further reflections is determined in a suitable manner.
Das Verfahren ist nicht darauf beschränkt, daß das Laserstrahlung reflektierende Teil hinter den zu fügenden Werkstücken angeordnet ist. Vorteilhafterweise wird es auch so ausgestaltet, daß ein Laserstrahlung reflektierendes Teil im Inneren mindestens eines Werkstücks oder zwischen beiden Werkstücken verwendet wird. Dadurch ist es insbesondere bei stärkeren Werkstücken möglich, z.B. bei Folien, Platten oder Halbzeugen, die Eindringtiefe der Laserstrahlung festzulegen. Ein derartiges Verfahren, wird beispielsweise beim Hohlraumschweißen verwendet, wo es darauf ankommt, daß die dem Laserstrahl abgewendete Wandfläche nicht aufgeschmolzen wird.The method is not restricted to the part reflecting the laser radiation being behind the part to be joined Workpieces is arranged. It is also advantageously designed such that a part reflecting laser radiation is used in the interior of at least one workpiece or between the two workpieces. This makes it possible to determine the penetration depth of the laser radiation, in particular in the case of thick workpieces, for example in the case of foils, plates or semi-finished products. Such a method is used, for example, in cavity welding, where it is important that the wall surface facing away from the laser beam is not melted.
In Ausgestaltung der Erfindung wird das Verfahren s o dur chgeführt , daß die Las er strahlung bei e inem Dur chs trahlen des energieabsorbierenden Werkstoffvolumens in einem den Winkel der Totalreflexion unterschreitenden Winkel auf eine das energieabsorbierende Werkstoffvolumen begrenzende Fläche eingestrahlt wird.In an embodiment of the invention, the method is carried out so that the laser radiation at a beam of the energy-absorbing material volume is irradiated onto an area that limits the energy-absorbing material volume at an angle below the total reflection angle.
D i e das en e r g i e ab sorbi er ende Werks to f fvo lumen be gr e nz ende Fläche kann von einem vorerwähnten, Laserstrahlung reflektierenden Teil gebildet werden. Totalreflexion ist jedoch auch an anderen Grenzflächen möglich, beispielsweise an der Grenzfläche des Werkstücks mit der Luft. Liegen infolge der entsprechenden Gestaltung der dem Verfahren dienenden Anordnung geeignete Grenzflächen vor, so bewirkt die Totalreflexion, daß die Laserstrahlung den Werkstoff bzw. das Werkstück nicht mehr verlassen kann und die Strahlungsenergie infolgedessen vollständig durch Werkstoffvolumen absorbiert wird.The surface of the work pot volume which is absorbable can be formed by a previously mentioned part which reflects laser radiation. However, total reflection is also possible at other interfaces, for example at the interface of the workpiece with the air. If suitable interfaces are present as a result of the corresponding design of the arrangement serving the method, the total reflection means that the laser radiation can no longer leave the material or the workpiece and the radiation energy is consequently completely absorbed by the volume of the material.
Um die Energieabsorption bei unterschiedlichen Gestaltungen der Werkstücke im Sinne möglichst vollständiger Energieabsorption beeinflussen zu können, wird die Laserstrahlung senkrecht oder parallel zur Fügeebene der Werkstücke in deren energieaabsorbierendes Werkstoffvolumen eingestrahlt. Die jeweils günstigste Einstrahlungsr ichtung wird durch die jeweils gegebene Fügegeometrie bestimmt, wie auch durch das angestrebte Ziel. Bei einem Verfahren mit r elativ zur Las erstrahlung bewegten Werkstücken kann es vorteilhaft sein, daß Laserstrahlung mit einem den Auf s chmelzberei ch in Bewegungsrichtung vergrößernden Querschnitt verwendet wird. Infolgedessen wird die Fügestelle in Bewegungsrichtung vergrößert und dadurch die Schmelztemperatur an den aufgeschmolzenen Stellen länger gehalten, damit die Schmelzen der Werkstücke besser ineinanderfließen. Dem gleichen Zweck der besseren Schmelzenmischung dient ein Verfahren, bei dem Laserstrahlung in einem Querschnitt verwendet wird, der zu einer Vorwärmung von Bereichen der der Fügezone unter gegenseitiger Annäherung zugeführten Werkstücke führt.In order to be able to influence the energy absorption in the case of different work piece designs in the sense of the most complete possible energy absorption, the laser radiation is irradiated perpendicular or parallel to the joining plane of the work pieces in their energy absorbing material volume. The most favorable direction of irradiation is determined by the given joining geometry, as well as by the desired goal. In a method with workpieces moving relative to the laser radiation, it may be advantageous to use laser radiation with a cross section that increases the melting range in the direction of movement. As a result, the joint is enlarged in the direction of movement, thereby keeping the melting temperature at the melted points longer so that the melts of the workpieces flow into one another better. The same purpose of better melt mixing is served by a method in which laser radiation is used in a cross-section which leads to preheating regions of the workpieces fed to the joining zone with mutual approximation.
Werden die Werkstücke mit Druck gefügt, so ergibt sich eine bessere Verbindung durch einen innigeren Kontakt des aufgeschmolzenen Werkstoffs der Werkstücke. Derartiger Druck wird durch Preßrollen, durch Preßgleiter oder durch eine starke Gasströmung nach Art des Preßschweißens erzielt. Derartiges Verfahren mit Druck wird insbesondere für Kunststoffolien angewendet.If the workpieces are joined with pressure, a better connection results from an intimate contact of the melted material of the workpieces. Such pressure is achieved by pressure rollers, by pressure glides or by a strong gas flow in the manner of pressure welding. Such a method with pressure is used in particular for plastic films.
Eine weitere Möglichkeit, die Verbindungsfeεtigkeit von Werkstücken zu fördern, liegt darin, daß die Werkstücke mit die gegenseitige Durchmischung des aufgeschmolzenen Werkstoffs fördernden gegenseitigen Verbindungs eingriffen verwendet werden. Eine darartige Formgestaltung der Werkstücke mit Verbindungseingriffen ist insbesondere für dickere Werkstücke geeignet, wie Platten oder Halbzeuge. Die speziell ausgebildeten Fügeflächen der zu verbindenden Werkstücke brauchen jedoch nicht präzise ausgeführt zu werden, da etwaige Toleranzen bzw. Abstände zwischen den Werkstücken beim Aufschmelzen des Werkstoffs verschwinden. Die Formgestaltung der Werkstücke bedeutet daher keinen großen Herstellungsaufwand.A further possibility for promoting the connection strength of workpieces is that the workpieces are used with mutual connections which promote the mutual mixing of the melted material. Such a design of the workpieces with connection interventions is particularly suitable for thicker workpieces, such as plates or semi-finished products. However, the specially designed joining surfaces of the workpieces to be connected do not need to be carried out precisely, since any tolerances or distances between the workpieces disappear when the material is melted. The shape of the workpieces therefore means no great manufacturing effort.
Es werden vorteilhafterweise Verbundfolien als Werkstücke verwendet, die mindestens eine thermoplastische Kunststoff schient als Fügeschicht haben und/oder die eine Laserstrahlung reflektierende Verbundschicht haben. Es ist infolgedessen möglich, auch solche Werkstoffe zu miteinander zu verbindenden Folien zu verarbeiten, die an sich einer durch Wärme wirkenden Verbindungstechnik nicht zugänglich sind, indem sie mit einer thermoplastischen Kunststoff Schicht als Fügeschicht versehen werden. Eine solche Verbundfolie kann also eine für einen bestimmten Einsatzzweck geeignete, aber nicht schweißbare Schicht haben, die mit einer für den bestimmten Einsatzzweck nicht geeigneten, jedoch zum Fügen dienenden Schicht versehen ist. Die Verbundfolie kann aber stattdessen oder auch zugleich eine Verbundschicht haben, die die Laserstrahlung reflektiert, um zu gewährleisten, daß die gesamte Strahlungsenergie zum Aufschmelzen der dem Fügen dienenden Schicht dient. Eine solche Strahlungsreflektierende Schicht ist entweder eine beidseitig umkleidete Einlageschicht, oder sie liegt einseitig offen, wobei die Strahlungsreflektierende Verbundschicht zugleich auch als Schicht mit einem weiteren speziellen Einsatzzweck dienen kann, beispielsweise der thermischen Abschirmung oder der hygienischen Aufbewahrung von Lebensmitteln.Composite foils are advantageously used as workpieces which have at least one thermoplastic have as a joining layer and / or have a composite layer reflecting a laser radiation. As a result, it is also possible to process such materials into foils to be joined to one another that are inherently inaccessible to a heat-acting joining technique by providing them with a thermoplastic layer as a joining layer. Such a composite film can therefore have a layer which is suitable but not weldable for a specific application and which is provided with a layer which is not suitable for the specific application but serves for joining. However, the composite film can instead or at the same time have a composite layer which reflects the laser radiation in order to ensure that the entire radiation energy is used to melt the layer serving for joining. Such a radiation-reflecting layer is either an insert layer covered on both sides, or it is open on one side, wherein the radiation-reflecting composite layer can also serve as a layer with a further special purpose, for example thermal shielding or hygienic storage of food.
Die Erfindung bezieht sich auch auf eine Vorrichtung zum Fügen von Werkstücken aus aufschmelzbarem Werkstoff mit Laserstrahlung, insbesondere für thermoplastische Kunststoffolien od.dgl., die auf eine Fügestelle der Werkstücke gerichtet ist und eine Energiedichte aufweist, die ein Aufschmelzen und Ineinanderfließen von Werkstoff im Bereich der Fügestelle durch Energieabsorption bewirkt. Um zu Erreichen, daß das Fügeverfahren ohne Verlustenergie und infolgedessen und wegen einer Ausschaltung von Wärmeleitung mit einer höheren Bearbeitungsgeschwindigkeit ermöglicht wird, ist die eingestrahlte Energie ausschließlich innerhalb des bestrahlten Werkstoffvolumens absorbiert.The invention also relates to a device for joining workpieces made of meltable material with laser radiation, in particular for thermoplastic plastic films or the like, which is aimed at a joint of the workpieces and has an energy density which allows material to melt and flow into one another Joining caused by energy absorption. In order to achieve that the joining process without loss of energy and, as a result, and because of the elimination of heat conduction, is made possible at a higher processing speed, the irradiated energy is absorbed only within the irradiated material volume.
Vorteilhafterweise hat sie mindestens einen Leitkörper zum Formen eines Fügespalts flexibler Werkstücke, und die Leitkörper sind Laserstrahlung reflektierend. Mit Hilfe der Leitkörper können die Werkstücke in eine für das Fügen dienliche Form gebracht werden und zugleich sind die Leitköroer so ausgestaltet, daß Energieverluste nicht auftreten können, weil die Laserstrahlung von ihnen in den Fügespalt bzw. in die miteinander zu verbindenden flexiblen Werkstücke reflektiert wird, wo sie dem Aufschmelzen des Werkstoffs dient. In spezieller Ausgestaltung weist sie polierte Leitflächen für die Verarbeitung thermoplastischer Kunststoffolien auf, wobei die Leitflächen nicht nur der Strahlungsreflexion dienen, sondern zugleich auch dem oberflächenschonenden Zuführen der Kunststoffolien.It advantageously has at least one guide body for forming a joint gap of flexible workpieces, and the Guides are reflective of laser radiation. With the help of the guide bodies, the workpieces can be brought into a shape that is useful for joining, and at the same time the guide bodies are designed in such a way that energy losses cannot occur because the laser radiation is reflected by them in the joint gap or in the flexible workpieces to be connected to one another, where it serves to melt the material. In a special embodiment, it has polished guide surfaces for processing thermoplastic plastic films, the guide surfaces not only serving for radiation reflection, but also for the surface-protecting feeding of the plastic films.
Die Vorrichtung ist besonders dann für das Verbinden von Kunststoffolien optimal, wenn sie einen parallel zur Fügeebene der thermoplastischen Kunststoffolien zugeführten Laserstrahl hat, und wenn die Breite und/oder die Länge des auf den Folien vorhandenen Strahlflecks einstellbar ist. In diesem Fall können die Folien durch eine geeignete Breite des Strahlflecks im gewünschten Sinne vor ihrem Zusammenführen vorgewärmt werden, nämlich mit der im Randbereich des Laserstrahls geringeren Energiedichte, während durch die Wahl der Länge des Strahlflecks derjenige Bereich des durch die Überlappung von Folien gebildeten Bereichs bestimmt wird, der aufgeschmolzen wird.The device is particularly optimal for connecting plastic films if it has a laser beam supplied parallel to the joining plane of the thermoplastic films and if the width and / or the length of the beam spot on the films can be adjusted. In this case, the films can be preheated in the desired sense by a suitable width of the beam spot, namely with the lower energy density in the edge area of the laser beam, while the area of the area formed by the overlapping of films is determined by the choice of the length of the beam spot is being melted.
Kurze Beschreibung der ZeichnungenBrief description of the drawings
Die Erfindung wird anhand von in der Zeichnung dargeste Ausführungsbeispielen erläutert. Es zeigt:The invention is explained with reference to exemplary embodiments shown in the drawing. It shows:
Fig. 1 eine Vorrichtung zur Herstellung von Endlosschla aus einer Folienbahn,1 shows a device for producing continuous loop from a film web,
Fig. 2 ein Diagramm zur Erklärung der Wirkung der Reflexion von Laserstrahlung in ein durchstrahltes Werkstück, Fig. 3, 4 Vorrichtungen zum Fügen von Folien, und Fig. 5a bis 1 Fügespalte bzw. Fügezonen von miteinande: zu verbindenden Werkstücken größerer Werkstoffstärken.2 is a diagram for explaining the effect of the reflection of laser radiation in a irradiated workpiece, 3, 4 devices for joining foils, and FIGS. 5a to 1 joining gaps or joining zones of mutually: workpieces of larger material thicknesses to be connected.
Beste Wege zur Ausfuhrung der ErfindungBest ways to carry out the invention
Gemäß Fig. 1 soll aus einem thermoplastischen Werkstück 1 in Gestalt einer flachen Kunststoffolie ein Schlauchbeutel 2 hergestellt werden, der eine Fügenaht 3 hat. Hierzu ist eine Folienführungsvorrichtung 5 erforderlich, die im wesentlichen aus der dargestellten Formschulter 6 besteht, welche eine Auflauffläche 6' für das Werkstück 1 hat. Die Auflauf fläche 6' geht in einen Schulterbereich 6'' über, von dem aus das Werkstück 1 mit den Kanten 1 ', 1 ' ' von einem Leitkörper 7 der Formschulter 6 tangential zusammengeführt wird, um die Fügestelle bzw. die Fügenaht 3 zu bilden. Außerdem ist ein Trichter 8 vorhanden, dessen Auslauf 9 in ein schlitzrohrartiges Ende 10 der Formschulter 6 gesteckt ist, so daß das Werkstück 1 entsprechend geführt ist, was der gewünschten Formung dient und zugleich das Befüllen des Schlauchbeutels 2 ermöglicht.1, a tubular bag 2 is to be produced from a thermoplastic workpiece 1 in the form of a flat plastic film, which has a seam 3. For this purpose, a film guiding device 5 is required, which essentially consists of the shaped shoulder 6 shown, which has a run-up surface 6 'for the workpiece 1. The ramp surface 6 'merges into a shoulder region 6' ', from which the workpiece 1 with the edges 1', 1 '' is tangentially brought together by a guide body 7 of the shaped shoulder 6 in order to form the joint or joint 3 . There is also a funnel 8, the outlet 9 of which is inserted into a slotted tube-like end 10 of the shaped shoulder 6, so that the workpiece 1 is guided accordingly, which serves the desired shaping and at the same time enables the tubular bag 2 to be filled.
Die Verbindung der Fügenaht 3 bzw. der Kanten 1 ' , 1 ' ' des Werkstücks 1 zu der Fügenaht 3 wird durch geeignete Strahlführung und Strahlformung des Laserstrahls 4 erreicht. Der Spiegel 11 dient der Reflexion des Laserstrahls 4 bei gleichzeitiger Umlenkung und Fokussierung auf die durch einen Kreis gekennzeichnete Fügestelle 12 zwischen Kanten des Leitkörpers 7. Die Fokussierung erfolgt beispielsweise derart, daß der Laserstrahl an der Fügestelle 12 einen Strahlfleck mit einer in der Richtung des Fügespalts im Vergleich zur Strahlbreite erheblichen Länge hat, um zu einer sicheren Fügung der Kanten 1 ', 1 ' ' zu kommen. Der Leitkörper 7 ist dadurch laserstrahlungsreflektierend, das er hochglanzpoliert oder oberflächenverspiegelt ist. Er reflektiert die durch das Werkstück 1 transmittierte Strahlung in das absorbierende Material zurück, wobei je nach Art des Werkstoffs auch eine mehrfache Reflexion zwischen den einander gegenüberliegenden Flächen des Leitkörpers 7 möglich ist, wenn diese dafür ausgebildet sind, beispielsweise genügend lang.The connection of the joining seam 3 or the edges 1 ′, 1 ″ of the workpiece 1 to the joining seam 3 is achieved by suitable beam guidance and beam shaping of the laser beam 4. The mirror 11 serves to reflect the laser beam 4 while simultaneously deflecting and focusing on the joint 12 marked by a circle between the edges of the guide body 7. The focusing takes place, for example, in such a way that the laser beam at the joint 12 has a beam spot with one in the direction of the joint gap compared to the beam width has considerable length in order to achieve a secure joining of the edges 1 ', 1''. The guide body 7 is reflective of laser radiation because it is highly polished or mirrored on the surface. It reflects the radiation transmitted through the workpiece 1 back into the absorbing material, and depending on the type of material, multiple reflection between the opposite surfaces of the guide body 7 is also possible, if these are designed for this, for example long enough.
Anhand von Fig. 2 wird das Grundsätzliche der Wirkung von durch ein Werkstück transmittierter Laserstrahlung für die Energieabsorption erläutert. Das Diagramm zeigt das Verhältnis l/lo eines in Richtung 13 auf ein Werkstück 14 gestrahlten Laserlichtstroms und dessen Verlauf in Abhängigkeit von der durchstrahlten Dicke des letzteren. Es ist ersichtlich, daß der Lichtstrom sich zunehmend verringert, bis er auf der Austrittsseite 15 das Werkstück 14 verläßt. Er trifft dann auf einen Reflektor 16, der laserstrahlungsreflektierend ist, so daß der Lichtstrom in der verbliebenen Stärke in das Werkstück 14 zurück eintritt. Er wird dort entsprechend der gestrichelten Kurve absorbiert, so daß eine vollständige Lichtstrom- bzw. Energieabsorption im Werkstück 14 vorliegt.. Da diese Energieabsorption mit einer Wärmeeinkoppelung verbunden ist, bedeutet die Absorption der reflektierten Laserstrahlung einen entsprechenden Wärmezuwachs im Werkstück 14 entsprechend der gestrichelten Fläche 17. Der reflektierte Strahlungs- bzw. Lichtstrom Itrans führt also zu einer entsprechend vergleichmäßigten Verteilung der Energie im Werkstück 14 und damit zu einer Vergleichmäßigung der Fügefestigkeit. Dies ist ein weiterer bedeutender Vorteil des erfindungsgemäßen Verfahrens außer der Verringerung der Energieverluste bzw. der Steigerung der Bearbeitungsgeschwindigkeit.The principle of the effect of laser radiation transmitted through a workpiece for energy absorption is explained with reference to FIG. 2. The diagram shows the ratio l / l o of a laser light beam radiated in the direction 13 onto a workpiece 14 and its course as a function of the irradiated thickness of the latter. It can be seen that the luminous flux decreases progressively until it leaves the workpiece 14 on the exit side 15. It then strikes a reflector 16, which is reflecting laser radiation, so that the luminous flux of the remaining strength enters the workpiece 14 again. It is absorbed there in accordance with the dashed curve, so that there is complete luminous flux or energy absorption in the workpiece 14. Since this energy absorption is associated with heat coupling, the absorption of the reflected laser radiation means a corresponding increase in heat in the workpiece 14 corresponding to the dashed area 17 The reflected radiation or luminous flux Itrans thus leads to a correspondingly uniform distribution of the energy in the workpiece 14 and thus to an equalization of the joining strength. This is a further significant advantage of the method according to the invention in addition to reducing the energy losses or increasing the processing speed.
Fig. 3 zeigt die Verbindung zweier als Folien ausgestalteter Werkstücke 1, die in ihren Vorschubrichtungen 18 von Leitkörpern 7 tangential zusammengeführt und von einem in Einstrahlungsrichtung 19 einfallenden Laserstrahl 4 mitein ander zu einer Dickfσlie 20 verbunden werden, die in Vorschubrichtung 21 abgezogen wird.FIG. 3 shows the connection of two workpieces 1 designed as foils, which are brought together tangentially in their feed directions 18 by guide bodies 7 and by a laser beam 4 incident in the direction of irradiation 19 be connected to a thick sheet 20 which is withdrawn in the feed direction 21.
Der Laserstrahl 4 ist derart fokussiert, daß er eine Strahlfleckbreite 22 hat, die die Dicke der herzustellenden Dickfolie 20 übersteigt. Infolgedessen werden die Folienwerks tücke 1 bereits vor ihrem Zusammenlaufen in Bereichen 23 erwärmt bzw. aufgeschmolzen, um in der Fügezone 24 miteinander verbunden zu werden. Soll eine derartige frühzeitige Erwärmung nicht erfolgen, so braucht der Laserstrahl 4 nur eine Strahlfleckbreite 22' aufzuweisen, die sich an dem Abstand der Leitkörper 7 im Bereich der Fügezone 24 orientiert.The laser beam 4 is focused in such a way that it has a beam spot width 22 which exceeds the thickness of the thick film 20 to be produced. As a result, the foil works 1 are heated or melted in regions 23 before they converge in order to be connected to one another in the joining zone 24. If such an early heating is not to take place, then the laser beam 4 need only have a beam spot width 22 ′ which is based on the spacing of the guide bodies 7 in the region of the joining zone 24.
Wenn die Folienwerks tücke 1 mit einer Strahlfleckbreite 22 bestrahlt werden und die Laserstrahlung zum Teil durchlassen, trifft diese auf Reflexionsflächen 25, von denen sie in den Werkstoff reflektiert wird, was durch die Pfeile 26 angedeutet ist. Die betreffenden Reflexionsflächen 25 sind wiederum hochglanzpoliert oder oberflächenverspiegelt, was allerdings nicht notwendig ist, wenn der ersichtliche Reflexionswinkel kleiner ist, als der Winkel der Totalreflexion an der Außenfläche 27 der Werkstücke 1.If the foil works 1 are irradiated with a beam spot width 22 and partially let the laser radiation pass through, this strikes reflection surfaces 25, from which it is reflected in the material, which is indicated by the arrows 26. The relevant reflection surfaces 25 are in turn highly polished or surface mirrored, although this is not necessary if the apparent reflection angle is smaller than the angle of total reflection on the outer surface 27 of the workpieces 1.
Fig. 4 zeigt eine der Fig. 3 ähnliche Anordnung mit Werkstücken 1, die aus Verbundfolie bestehen. Jedes Werkstück 1 hat eine Außenschicht 28, eine Fügeschicht 29, die also dem Fügen beider Werkstücke 1 zu einer Dickfolie 20' dienen sowie eine von den Schichten 28, 29 eingebettete Aluminiumschicht 30, die der Reflexion von Anteilen des Laserstrahls 4 dient, welche die Fügeschicht 29 durchstrahlen. In diesem Fall ist es nicht nötig, daß die Leitkörper 7 strahlungsreflektier ende Eigenschaften haben, oder daß durch die Anordnung der Werkstücke 1 einerseits und die Bemessung bzw. Fokussierung des Laserstrahls 4 andererseits auf eine etwaige Totalreflexion an der mittleren Schicht Rücksicht genommen wird. Die Fig. 5a bis 5i zeigen unterschiedliche Gestaltungen von Fügespalten bzw. Fügezonen bei Werkstücken größerer Dicke. Fig. 5a zeigt einen stumpfen Stoß zweier plattenförmiger Werkstücke 31 mit einem zu ihnen vertikalen Fügespalt 32 und einer Fügezone 33, deren Breite durch die Breite 22 des Strahlflecks des Laserstrahls 4 bestimmt wird. Gemäß Fig. 5b ist der Fügespalt 32 derart schräg in der Fügezone 33 angeordnet, daß sie sich über deren gesamte Breite erstreckt. Fig. 5c zeigt zwei plattenförmige Werkstücke 31 mit einem Überlappungsstoß, bei dem die Überlappungsflache in Plattenmittelebene angeordnet ist. Im Vergleich dazu ist der Stoß gemäß Fig. 5d einfach keilförmig, wobei alle Flächenabschnitte eines Werkstücks 31 innerhalb der Fügezone 33 liegen. Gemäß Fig. 5e sind die Werkstücke 31 nut-federartig und gemäß Fig. 5f doppel- keilförmig bzw. verzahnt miteinander in Eingriff. Hierdurch wird die Verbindungsfestigkeit der Werkstücke 31 mittels besserer Durchmischung der Schmelzen erreicht. Die Fig. 5g, h zeigen einen einfachen Überlappungsstoß bzw. einen unter Absetzungen von Werkstücken 31 gebildeten Überlappungsstoß, wobei die Fügezone 33 jeweils der Überlappungsbreite entspricht. Fig. 5i zeigt eine Flanschverbindung zweier als Halbzeug gestalteter Werkstücke 31*, bei denen die aneinandergrenzenden Flächen doppelkeilförmigen Querschnitt aufweisen, etwa gemäß Fig. 5f, wobei aber die Breite 22 des Strahlfiecks des Laserstrahls 4 gleich der Gesamtbreite des Verbindungsflansches ist. Zusammenfassend läßt sich feststellen, daß die Durchmischung der Werkstoffschmelze um so besser ist, je tiefer die gegenseitigen Verbindungseingriffe der Werkstücke 31, 31' sind, und je größer der Anteil zur Werkstückebene geneigter Verbindungsflächen ist.FIG. 4 shows an arrangement similar to FIG. 3 with workpieces 1 which consist of composite film. Each workpiece 1 has an outer layer 28, a joining layer 29, which thus serve to join both workpieces 1 to form a thick film 20 ', and an aluminum layer 30 embedded by the layers 28, 29, which serves to reflect portions of the laser beam 4 which form the joining layer 29 shine through. In this case, it is not necessary that the guide bodies 7 have radiation-reflecting properties, or that due to the arrangement of the workpieces 1 on the one hand and the dimensioning or focusing of the laser beam 4 on the other hand, any total reflection on the middle layer is taken into account. 5a to 5i show different designs of joining gaps or joining zones in the case of workpieces of greater thickness. 5a shows a butt joint of two plate-shaped workpieces 31 with a joining gap 32 vertical to them and a joining zone 33, the width of which is determined by the width 22 of the beam spot of the laser beam 4. 5b, the joining gap 32 is arranged obliquely in the joining zone 33 in such a way that it extends over its entire width. 5c shows two plate-shaped workpieces 31 with an overlap joint in which the overlap area is arranged in the plate center plane. In comparison, the joint according to FIG. 5 d is simply wedge-shaped, with all surface sections of a workpiece 31 lying within the joining zone 33. According to FIG. 5e, the workpieces 31 are tongue and groove-like and, according to FIG. 5f, double wedge-shaped or toothed. As a result, the connection strength of the workpieces 31 is achieved by better mixing of the melts. 5g, h show a simple overlap joint or an overlap joint formed by the depositing of workpieces 31, the joining zone 33 in each case corresponding to the overlap width. FIG. 5i shows a flange connection of two workpieces 31 * designed as semifinished products, in which the adjoining surfaces have a double wedge-shaped cross section, for example according to FIG. 5f, but the width 22 of the beam spot of the laser beam 4 is equal to the total width of the connecting flange. In summary, it can be stated that the mixing of the molten material is better, the deeper the mutual engagement of the workpieces 31, 31 ', and the greater the proportion of the connecting surfaces inclined to the workpiece plane.
Die Fig. 5k, 1 zeigen plattenartige Werkstücke 31 in stumpf gestoßener Anordnung und mit einer Vielzahl von Verbindungseingriffen bzw. mit einem entsprechend mäanderförmigen Fügespalt 32, der sich über die gesamte Breite der Fügezone 33 erstreckt. Eine Besonderheit ist die Anordnung eines Re flektorstreifens 34, der verhindert, daß die in Richtung 35 eingestrahlte Laser Strahlung die Werkstücke 31 vollständig durchsetzt. Vielmehr wird die Laserstrahlung reflektiert und dadurch die Tiefe der Fügezone 33 bestimmt. Die beiden Ausführungsformen unterscheiden sich dadurch, daß das reflektierende Teil 34 bei Fig. 5k im Fügespalt 32 zwischen den Werkstücken 31 angeordnet ist, wozu der Fügespalt 32 im Querschnit entsprechend vergrößert ausgebildet sein muß. Bei der Ausführungsform gemäß Fig. 51 ist das reflektierende Teil 34 innerhalb des linken Werkstücks 31 in einer entsprechend geformten Nut angeordnet.5k, 1 show plate-like workpieces 31 in a butt-jointed arrangement and with a large number of connection interventions or with a corresponding meandering joining gap 32 which extends over the entire width of the joining zone 33. A special feature is the arrangement of a Re flektorstreifens 34, which prevents the laser radiation radiated in the direction 35 completely penetrates the workpieces 31. Rather, the laser radiation is reflected, thereby determining the depth of the joining zone 33. The two embodiments differ in that the reflecting part 34 in FIG. 5k is arranged in the joining gap 32 between the workpieces 31, for which purpose the joining gap 32 must be of correspondingly enlarged cross-section. 51, the reflecting part 34 is arranged inside the left workpiece 31 in a correspondingly shaped groove.
Die vorbeschriebenen Verfahren werden beispielsweise mit einem Laserstrahl eines Kohlendioxidlasers durchgeführt, wobei die Strahlführung der Anwendung angepaßt werden kann. Die Strahlführung kann dreidimensional gesteuert werden, so daß das Verfahren sehr anpassungsfähig ist, wenn mit den herkömmlichen Fügeverfahren verglichen wird. Das Verfahren ist insbesondere bei dünnen Folien von 10 Mikrometer bis 1 Millimeter vorteilhaft anwendbar, weil die Kunststoffe bei derartigen Materialstärken häufig Strahlung transmittieren, die sonst verlorengeht.The above-described methods are carried out, for example, with a laser beam from a carbon dioxide laser, it being possible for the beam guidance to be adapted to the application. The beam guidance can be controlled three-dimensionally, so that the method is very adaptable when compared with the conventional joining methods. The method can be used with particular advantage in the case of thin films of 10 micrometers to 1 millimeter, because with such material thicknesses the plastics often transmit radiation which would otherwise be lost.
Gewerbliche Ver wertbarkeitCommercial usability
Das erfindungsgemäße Verfahren dient zum Fügen von Werkstücken aus aufschmelzbarem Werkstoff mit Laserstrahlung. The method according to the invention is used for joining workpieces made of meltable material with laser radiation.

Claims

Ansprüche Expectations
1. Verfahren zum Fügen von Werkstücken aus auf schmelzbarem Werkstoff mit Laserstrahlung, die auf eine Fügestelle der insbesondere aus thermoplastischem Kunststoff bestehenden Werkstücke gerichtet und mit einer Energiedichte angewendet wird, die ein Aufschmelzen und Ineinanderfließen von Werkstoff im Bereich der Fügestelle durch Energieabsorption bewirkt, d a d u r c h g e k e n n z e i c h n e t, daß die Werkstückbestrahlung im Sinne vollständiger Energieabsorption ausschließlich durch Werkstoffvolumen der Werkstücke (1, 14, 31, 31') durchgeführt wird.1. A method for joining workpieces made of fusible material with laser radiation, which is directed at a joint of the workpieces, in particular consisting of thermoplastic, and is used with an energy density which causes material to melt and flow into one another in the region of the joint by energy absorption, characterized in that that the workpiece irradiation in the sense of complete energy absorption is carried out exclusively by the material volume of the workpieces (1, 14, 31, 31 ').
2. Verfahren nach Anspruch 1, d a d u r c h g e k e n n z e i c h n e t, daß das Energieabsorptionsvermögen des Werkstoffs mit Zusatzstoffen beeinflußt wird, die dem Werkstoff bei dessen Herstellung beigegeben werden.2. The method of claim 1, d a d u r c h g e k e n n z e i c h n e t that the energy absorption capacity of the material is influenced with additives that are added to the material during its manufacture.
3. Verfahren nach Anspruch 1 oder 2, d a d u r c h g e k e n n z e i c h n e t, daß die Energieabsorption im Werkstoff durch eine Auswahl der Wellenlänge der Laserstrahlung beeinflußt wird.3. The method of claim 1 or 2, d a d u r c h g e k e n n z e i c h n e t that the energy absorption in the material is influenced by a selection of the wavelength of the laser radiation.
4. Verfahren nach einem oder mehreren der Anprüche 1 bis 3, bei dem Prozeßparameter geregelt werden, d a d u r c h g e k e n n z e i c h n e t, daß die Regelung in Abhängigkeit von der fortwährend gemessenen Schmelzentemperatur erfolgt.4. The method according to one or more of claims 1 to 3, in which process parameters are controlled, so that the control is carried out as a function of the continuously measured melt temperature.
Verfahren nach einem der Ansprüche 1 bis 4, bei dem in Bestrahlungsrichtung hinter dem energieabsorbierenden Werkstoffvolumen ein energierückεtrahlendes Teil verwendet wird, d a d u r c h g e k e n n z e i c h n e t, daß mindestens ein die Laserstrahlung reflektierendes Teil (z.B. Leitkōrper 7, Reflektor streif en 34) verwendet wird.Method according to one of Claims 1 to 4, in which an energy-reflecting part is used behind the energy-absorbing material volume in the radiation direction, characterized in that that at least one part reflecting the laser radiation (eg guide body 7, reflector strip 34) is used.
6. Verfahren nach einem der Ansprüche 1 bis 5, d a d u r c h g e k e n n z e i c h n e t, daß ein Laserstrahlung reflektierendes Teil (z.B. Reflektorstreifen 34) im Inneren mindestens eines Werkstücks (1, 31, 31') oder zwischen beiden Werkstücken verwendet wird.6. The method according to any one of claims 1 to 5, so that a part reflecting laser radiation (e.g. reflector strips 34) is used in the interior of at least one workpiece (1, 31, 31 ') or between the two workpieces.
7. Verfahren nach einem der Ansprüche 1 bis 6, d a d u r c h g e k e n n z e i c h n e t, daß die Laserstrahlung bei einem Durchstrahlen des energieabsorbierenden Werkstoffvolumens in einem den Winkel der Totalreflexion unterschreitenden Winkel auf eine das energieabsorbierende Werkstoffvolumen begrenzende Fläche eingestrahlt wird.7. The method according to any one of claims 1 to 6, so that the laser radiation is irradiated when the energy-absorbing material volume is irradiated at an angle falling below the angle of total reflection onto a surface which limits the energy-absorbing material volume.
8. Verfahren nach einem der Ansprüche 1 bis 7, d a d u r c h g e k e n n z e i c h n e t, daß die Laser Strahlung senkrecht oder parallel zur Fügeebene der Werkstücke (1, 31, 3 in deren energieabsorbierendes Werkstoffvolumen eingestrahlt wird.8. The method according to any one of claims 1 to 7, that the laser radiation is irradiated perpendicularly or parallel to the joining plane of the workpieces (1, 31, 3) in their energy-absorbing material volume.
9. Verfahren nach einem der Ansprüche 1 bis 8, mit relativ zur Laserstrahlung bewegten Werkstücken, d a d u r c h g e k e n n z e i c h n e t, daß Laserstrahlung mit einem den Auf schmelzbereich in Bewegungsrichtung vergrößernden Querschnitt verwendet wird.9. The method according to any one of claims 1 to 8, with workpieces moving relative to the laser radiation, so that laser radiation is used with a cross-section which increases the melting range in the direction of movement.
10. Verfahren nach einem der Ansprüche 1 bis 9, d a d u r c h g e k e n n z e i c h n e t, daß Laserstrahlung in einem10. The method according to any one of claims 1 to 9, d a d u r c h g e k e n n z e i c h n e t that laser radiation in one
Querschnitt verwendet wird, der zu einer Vorwärmung von Bereichen der der Fügezone unter gegenseitiger Annäherung zugeführten Werkstücke (1) führt. Cross-section is used which leads to preheating areas of the workpieces (1) fed to the joining zone with mutual approximation.
11. Verfahren nach einem der Ansprüche 1 bis 10, d a d u r c h g e k e n n z e i c h n e t, daß die Werkstücke (1, 31, 31') mit Druck gefügt werden.11. The method according to any one of claims 1 to 10, so that the workpieces (1, 31, 31 ') are joined with pressure.
12. Verfahren nach einem der Ansprüche 1 bis 11, d a d u r c h g e k e n n z e i c h n e t, daß die Werkstücke (31, 31') mit die gegenseitige Durchmischung des aufgeschmolzenen Werkstoffs fördernden gegenseitigen Verbindungseingriffen verwendet werden.12. The method according to any one of claims 1 to 11, that the workpieces (31, 31 ') are used with mutual connection interventions which promote the mutual mixing of the melted material.
13. Verfahren nach einem der Ansprüche 1 bis 12, d a d u r c h g e k e n n z e i c h n e t, daß Verbundfolien als Werkstücke (1) verwendet werden, die mindestens eine thermoplastische KunststoffSchicht als Fügeschicht (29) haben und/oder die eine Las erstrahlung reflektierende Verbundschicht (Aluminiumschicht 30) haben.13. The method according to any one of claims 1 to 12, so that composite foils are used as workpieces (1) which have at least one thermoplastic plastic layer as the joining layer (29) and / or which have a composite layer reflecting laser radiation (aluminum layer 30).
14. Vorrichtung zum Fügen von Werkstücken aus aufschmelzbarem Werkstoff mit Laserstrahlung, insbesondere für thermoplastische Kunststoffolien od.dgl., die auf eine14. Device for joining workpieces made of meltable material with laser radiation, in particular for thermoplastic plastic films or the like
Fügestelle der Werkstücke gerichtet ist und eine Energiedichte aufweist, die ein Aufschmelzen und Ineinanderfließen von Werkstoff im Bereich der Fügestelle durch Energieabsorption bewirkt, d a d u r c h g e k e n n z e i c h n e t, daß eingestrahlte Energie ausschließlich innerhalb des bestrahlten Werkstoffvolumens absorbiert ist.Joining the workpieces is directed and has an energy density, which causes melting and flowing together of material in the area of the joint by energy absorption, so that radiated energy is absorbed only within the irradiated material volume.
15. Vorrichtung nach Anspruch 14, d a d u r c h g e k e n n z e i c h n e t, daß sie mindestens einen Leitkörper (7) zum Formen eines Fügespalts (32) flexibler Werkstücke (1) hat, und daß die Leitkörper (7) Laserstrahlung reflektierend sind.15. The apparatus according to claim 14, d a d u r c h g e k e n n z e i c h n e t that it has at least one guide body (7) for forming a joint gap (32) of flexible workpieces (1), and that the guide body (7) are laser radiation reflective.
16. Vorrichtung nach Anspruch 14 oder 15, d a d u r c h g e k e n n z e i c h n e t, daß sie polierte Leit flächen für die Verarbeitung thermoplastischer Kunststofffolien aufweist.16. The apparatus according to claim 14 or 15, characterized in that it is polished Leit has surfaces for processing thermoplastic plastic films.
17. Vorrichtung nach einem oder mehreren der Ansprüche 14 bis 16, d a d u r c h g e k e n n z e i c h n e t, daß sie einen parallel zur Fügeebene der thermoplastischen Kunststoffolien zugeführten Laserstrahl (4) hat, und daß die Breite (22) und/oder die Länge des auf den Folien vorhandenen Strahlflecks einstellbar ist. 17. The device according to one or more of claims 14 to 16, characterized in that it has a laser beam (4) supplied parallel to the joining plane of the thermoplastic plastic films, and that the width (22) and / or the length of the beam spot present on the films is adjustable is.
PCT/DE1989/000247 1988-04-22 1989-04-21 Process for joining workpieces made of fusible material using a laser beam WO1989010231A1 (en)

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DE3813570A1 (en) 1989-11-09
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