WO1988000126A1 - Flat extruding head for plastic film - Google Patents

Flat extruding head for plastic film Download PDF

Info

Publication number
WO1988000126A1
WO1988000126A1 PCT/EP1987/000330 EP8700330W WO8800126A1 WO 1988000126 A1 WO1988000126 A1 WO 1988000126A1 EP 8700330 W EP8700330 W EP 8700330W WO 8800126 A1 WO8800126 A1 WO 8800126A1
Authority
WO
WIPO (PCT)
Prior art keywords
film
blowing means
air
lip
head
Prior art date
Application number
PCT/EP1987/000330
Other languages
French (fr)
Inventor
Lanfranco Dolci
Dario Brambilla
Original Assignee
Ing. L. Dolci S.P.A.
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 Ing. L. Dolci S.P.A. filed Critical Ing. L. Dolci S.P.A.
Publication of WO1988000126A1 publication Critical patent/WO1988000126A1/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
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/88—Thermal treatment of the stream of extruded material, e.g. cooling
    • B29C48/911—Cooling
    • B29C48/9135—Cooling of flat articles, e.g. using specially adapted supporting means
    • B29C48/915—Cooling of flat articles, e.g. using specially adapted supporting means with means for improving the adhesion to the supporting means
    • B29C48/917—Cooling of flat articles, e.g. using specially adapted supporting means with means for improving the adhesion to the supporting means by applying pressurised gas to the surface of the flat article
    • 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
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/07—Flat, e.g. panels
    • B29C48/08—Flat, e.g. panels flexible, e.g. films
    • 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
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/88—Thermal treatment of the stream of extruded material, e.g. cooling
    • B29C48/911—Cooling
    • B29C48/9135—Cooling of flat articles, e.g. using specially adapted supporting means
    • B29C48/914—Cooling of flat articles, e.g. using specially adapted supporting means cooling drums
    • 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
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/88—Thermal treatment of the stream of extruded material, e.g. cooling
    • B29C48/911—Cooling
    • B29C48/9135—Cooling of flat articles, e.g. using specially adapted supporting means
    • B29C48/915—Cooling of flat articles, e.g. using specially adapted supporting means with means for improving the adhesion to the supporting means
    • B29C48/916—Cooling of flat articles, e.g. using specially adapted supporting means with means for improving the adhesion to the supporting means using vacuum
    • 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
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/92—Measuring, controlling or regulating
    • 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
    • B29C2948/00—Indexing scheme relating to extrusion moulding
    • B29C2948/92—Measuring, controlling or regulating
    • B29C2948/92504—Controlled parameter
    • B29C2948/92609—Dimensions
    • B29C2948/92647—Thickness
    • 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
    • B29C2948/00—Indexing scheme relating to extrusion moulding
    • B29C2948/92—Measuring, controlling or regulating
    • B29C2948/92819—Location or phase of control
    • B29C2948/92923—Calibration, after-treatment or cooling zone

Definitions

  • the present invention concerns an apparatus for extruding film comprising a flat extrusion head, a cooled rotating roller positioned below the head, a blowing means that directs an adjustable amount of air onto the film according to the desired thickness.
  • the thickness of a flat film is adjusted by operating the extrusion head which is substantially made up of a fixed lip joined to a movable lip thus forming a slit through which the molten plastic passes.
  • the conventional systems vary the width of the slit by means of bolts or, automatically, by means of heated blocks, one end of them operating the said movable lip.
  • the bolts i.e. by lengthening or shortening the blocks under the effect of thermal expansion, the movable lip is brought closer or further away from the fixed one with a consequent variation of the width of the slit at that point. This method of adjustment is however slow and not very accurate.
  • the main aim of the present invention is to create an apparatus that permits thickness adjustment of extruded flat film without the above drawbacks, that is achieving practically immediate thickness adjustment and extremely high precision at any moment of the extrusion, eliminating at the same time any maintenance problem.
  • the apparatus comprises a flat extrusion head, a cooled rotating roller positioned below the head, a blowing means that directs an adjustable amount of air onto the film and is characterized by a blowing means consisting of a single slit formed by two lips, at least one of which is locally movable with respect to the opposite lip.
  • An air sucking means is also envisaged in the apparatus, said means being set opposite the blowing means on the other side of the film, so that the blowing means presses the film against the rotating roller, while the sucking means draws in the air left between the film and the roller.
  • the movable lip is moved by blocks heated by resistors and cooled by air circulating in special ducts.
  • Fig. 1 shows a schematic side view of the plant for production of flat film.
  • Fig. 2 shows an enlarged side view, partially in section, of the thickness adjusting means; and
  • Fig. 3 shows a front view of said means.
  • Figure 1 shows the flat extruding head 10 having an extrusion slit 20 which lays the film P in its semi-fluid state onto the cooled roller 11 which rotates in the direction of arrow F.
  • the air which at the same time adjusts the thickness of the film and makes it adhere to the cooling roller 11, comes out from blowing means 12.
  • the amount of air is automatically and suitably adjusted so as to obtain the required film thickness.
  • Figure 2 shows the thickness adjusting means according to a preferred embodiment. It consists of a blowing means 12, forming an air blade directing a controlled amount of air onto the film. The jet of air needed for adjustment passes thorugh a fixed lip 14 and a movable lip 15.
  • the two lips 14 and 15 form a slit 1-7 through which passes the desired amount of air forming the air blade required to adjust the thickness of film P.
  • the width of slit 17 is adjusted by shifting the movable lip 15 on which adjustment members 16 operate.
  • movable lip 15 which is carried out by means of a series of adjusting members 16 possibly made up of stretchable rods, can be carried out manually or, preferably, automatically. If adjustment is automatic, the use of resistors 22 and of cooling air is envisaged, the latter entering by duct 16a and exiting by duct 16b.
  • Adjusting means 16 can consist either of adjusting screws 21 or of heated blocks.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Extrusion Moulding Of Plastics Or The Like (AREA)

Abstract

The apparatus comprises a flat extrusion head (10), a rotating cooling roller (11), a blowing means (12) that directs an adjustable amount of air onto the film (P), while said film (P) is spread on the cooled rotating roller (11), the blowing means (12) consisting of a slit (17) formed between two opposite lips (14, 15). Preferably one lip (14) is fixed and the other (15) is movable and comprises means for adjusting the slit (17). Use of a sucking means (13) positioned opposite the blowing means (12) with respect to the film (P) is also envisaged.

Description

"FLAT EXTRUDING HEAD FOR PLASTIC FILM"
The present invention concerns an apparatus for extruding film comprising a flat extrusion head, a cooled rotating roller positioned below the head, a blowing means that directs an adjustable amount of air onto the film according to the desired thickness.
At present the thickness of a flat film is adjusted by operating the extrusion head which is substantially made up of a fixed lip joined to a movable lip thus forming a slit through which the molten plastic passes. The conventional systems vary the width of the slit by means of bolts or, automatically, by means of heated blocks, one end of them operating the said movable lip. By acting on the bolts i.e. by lengthening or shortening the blocks under the effect of thermal expansion, the movable lip is brought closer or further away from the fixed one with a consequent variation of the width of the slit at that point. This method of adjustment is however slow and not very accurate. In fact neither a manual nor an automatic adjustment based on the expansion, or shortening of the blocks can act immediately, as would be desirable. The whole adjustment apparatus is subjected to high temperature and to the extruder head temperature differences. Adjustment is therefore inaccurate and proves difficult to maintain. Finally, if a machine stoppage occurs, restoring operation of the said machine is a slow procedure owing to the complicated thickness-adjusting procedure itself. The extruded film can thus present faults liable to alter the quality of the end product.
The main aim of the present invention is to create an apparatus that permits thickness adjustment of extruded flat film without the above drawbacks, that is achieving practically immediate thickness adjustment and extremely high precision at any moment of the extrusion, eliminating at the same time any maintenance problem.
The apparatus according to the present invention comprises a flat extrusion head, a cooled rotating roller positioned below the head, a blowing means that directs an adjustable amount of air onto the film and is characterized by a blowing means consisting of a single slit formed by two lips, at least one of which is locally movable with respect to the opposite lip. An air sucking means is also envisaged in the apparatus, said means being set opposite the blowing means on the other side of the film, so that the blowing means presses the film against the rotating roller, while the sucking means draws in the air left between the film and the roller.
The movable lip is moved by blocks heated by resistors and cooled by air circulating in special ducts.
The invention will now be better illustrated by a non-restrictive exemplary embodiment shown in the enclosed drawings, wherein:
Fig. 1 shows a schematic side view of the plant for production of flat film. Fig. 2 shows an enlarged side view, partially in section, of the thickness adjusting means; and Fig. 3 shows a front view of said means.
Figure 1 shows the flat extruding head 10 having an extrusion slit 20 which lays the film P in its semi-fluid state onto the cooled roller 11 which rotates in the direction of arrow F. The air which at the same time adjusts the thickness of the film and makes it adhere to the cooling roller 11, comes out from blowing means 12. The amount of air is automatically and suitably adjusted so as to obtain the required film thickness.
On the opposite side of the film P from the blowing means 12 there is an air sucking means 13 capable of drawing in the amount of air comprised between the film and the rotating roller 11. Figure 2 shows the thickness adjusting means according to a preferred embodiment. It consists of a blowing means 12, forming an air blade directing a controlled amount of air onto the film. The jet of air needed for adjustment passes thorugh a fixed lip 14 and a movable lip 15.
The two lips 14 and 15 form a slit 1-7 through which passes the desired amount of air forming the air blade required to adjust the thickness of film P. The width of slit 17 is adjusted by shifting the movable lip 15 on which adjustment members 16 operate.
The adjustment of movable lip 15, which is carried out by means of a series of adjusting members 16 possibly made up of stretchable rods, can be carried out manually or, preferably, automatically. If adjustment is automatic, the use of resistors 22 and of cooling air is envisaged, the latter entering by duct 16a and exiting by duct 16b.
Adjusting means 16 can consist either of adjusting screws 21 or of heated blocks.

Claims

C L A I M S
1. A film extrusion apparatus comprising a flat extrusion head (10), a rotating cooling roller positioned below the head (10), blowing means conveying an adjustable amount of air onto the film according to the desired thickness, characterized in that the blowing means (12) consists of a single slit (17) formed by two lips (14, 15), at least one of said lips (15) being locally movable with respect to the opposite lip (14).
2. An apparatus according to claim 1, characterized in that a sucking means (13) is also envisaged, set opposite the blowing means (12), on the other side of the film, so that the blowing means (12) presses the film against the rotating roller (11) while the sucking means (12) sucks the air from between the film (P) and the roller (11).
3. An apparatus according to any one of the preceding claims, characterized in that the movable lip (15) is moved by blocks automatically heated by resistors, said blocks being alternately cooled by air circulating in special ducts (16a, 16b).
PCT/EP1987/000330 1986-06-27 1987-06-24 Flat extruding head for plastic film WO1988000126A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT20944/86A IT1191819B (en) 1986-06-27 1986-06-27 PROCEDURE AND RELATED EQUIPMENT FOR THE ADJUSTMENT OF THE THICKNESS OF A FLAT FILM
IT20944A/86 1986-06-27

Publications (1)

Publication Number Publication Date
WO1988000126A1 true WO1988000126A1 (en) 1988-01-14

Family

ID=11174423

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP1987/000330 WO1988000126A1 (en) 1986-06-27 1987-06-24 Flat extruding head for plastic film

Country Status (3)

Country Link
AU (1) AU7694287A (en)
IT (1) IT1191819B (en)
WO (1) WO1988000126A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2698580A1 (en) * 1992-12-01 1994-06-03 Albert Plastiques Suction-type applicator device - for applying extruded plastics film onto cooling roll

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3141194A (en) * 1962-02-09 1964-07-21 Avisun Corp Gas delivery nozzle for film casting apparatus
FR1538880A (en) * 1966-09-22 1968-09-06 British Sidac Ltd Process for the production of thin and uniform films of hygroscopic materials
DE2658518A1 (en) * 1976-12-23 1978-06-29 Reifenhaeuser Kg Automatic thickness control of blown thermoplastic tubing - by air jets playing on parts showing deviation from nominal value
US4209475A (en) * 1978-10-20 1980-06-24 Mobil Oil Corporation Method and apparatus for effecting uniform film thickness
US4255365A (en) * 1979-01-23 1981-03-10 E. I. Du Pont De Nemours And Company Pneumatic gauge adjustment of edge-pinned cast web

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3141194A (en) * 1962-02-09 1964-07-21 Avisun Corp Gas delivery nozzle for film casting apparatus
FR1538880A (en) * 1966-09-22 1968-09-06 British Sidac Ltd Process for the production of thin and uniform films of hygroscopic materials
DE2658518A1 (en) * 1976-12-23 1978-06-29 Reifenhaeuser Kg Automatic thickness control of blown thermoplastic tubing - by air jets playing on parts showing deviation from nominal value
US4209475A (en) * 1978-10-20 1980-06-24 Mobil Oil Corporation Method and apparatus for effecting uniform film thickness
US4255365A (en) * 1979-01-23 1981-03-10 E. I. Du Pont De Nemours And Company Pneumatic gauge adjustment of edge-pinned cast web

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2698580A1 (en) * 1992-12-01 1994-06-03 Albert Plastiques Suction-type applicator device - for applying extruded plastics film onto cooling roll

Also Published As

Publication number Publication date
AU7694287A (en) 1988-01-29
IT1191819B (en) 1988-03-23
IT8620944A1 (en) 1987-12-27
IT8620944A0 (en) 1986-06-27

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