EP0221224A1 - Presse pour l'obtention d'objets exigeant pour leur fabrication industrielle, une étape de préformage avec faible dépense d'effort, et une pression finale élevée - Google Patents

Presse pour l'obtention d'objets exigeant pour leur fabrication industrielle, une étape de préformage avec faible dépense d'effort, et une pression finale élevée Download PDF

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Publication number
EP0221224A1
EP0221224A1 EP85830252A EP85830252A EP0221224A1 EP 0221224 A1 EP0221224 A1 EP 0221224A1 EP 85830252 A EP85830252 A EP 85830252A EP 85830252 A EP85830252 A EP 85830252A EP 0221224 A1 EP0221224 A1 EP 0221224A1
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EP
European Patent Office
Prior art keywords
punch
press
powder
movable
piece
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP85830252A
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German (de)
English (en)
Inventor
Enzo Mantegani
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Individual
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Individual
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Publication date
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Priority to EP85830252A priority Critical patent/EP0221224A1/fr
Publication of EP0221224A1 publication Critical patent/EP0221224A1/fr
Withdrawn legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B5/00—Producing shaped articles from the material in moulds or on moulding surfaces, carried or formed by, in or on conveyors irrespective of the manner of shaping
    • B28B5/04—Producing shaped articles from the material in moulds or on moulding surfaces, carried or formed by, in or on conveyors irrespective of the manner of shaping in moulds moved in succession past one or more shaping stations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B13/00—Feeding the unshaped material to moulds or apparatus for producing shaped articles; Discharging shaped articles from such moulds or apparatus
    • B28B13/02—Feeding the unshaped material to moulds or apparatus for producing shaped articles
    • B28B13/0215—Feeding the moulding material in measured quantities from a container or silo
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B3/00—Producing shaped articles from the material by using presses; Presses specially adapted therefor
    • B28B3/003—Pressing by means acting upon the material via flexible mould wall parts, e.g. by means of inflatable cores, isostatic presses
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B5/00—Producing shaped articles from the material in moulds or on moulding surfaces, carried or formed by, in or on conveyors irrespective of the manner of shaping
    • B28B5/06—Producing shaped articles from the material in moulds or on moulding surfaces, carried or formed by, in or on conveyors irrespective of the manner of shaping in moulds on a turntable
    • B28B5/08—Producing shaped articles from the material in moulds or on moulding surfaces, carried or formed by, in or on conveyors irrespective of the manner of shaping in moulds on a turntable intermittently rotated
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B11/00—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses
    • B30B11/001—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses using a flexible element, e.g. diaphragm, urged by fluid pressure; Isostatic presses
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B11/00—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses
    • B30B11/02—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses using a ram exerting pressure on the material in a moulding space
    • B30B11/08—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses using a ram exerting pressure on the material in a moulding space co-operating with moulds carried by a turntable
    • B30B11/10—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses using a ram exerting pressure on the material in a moulding space co-operating with moulds carried by a turntable intermittently rotated
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
    • B30B15/30—Feeding material to presses
    • B30B15/302—Feeding material in particulate or plastic state to moulding presses

Definitions

  • This invention relates to a press particularly suitable for the manufacture of pieces and items of any shape, profile, depth and thickness, such, for example, as plates, cups, salad bowls, vases, special tiles having irregular shape and surfaces, particularly shaped small parts or mechanical elements, etc., all of which are obtained by pressing into shapes ceramic, refractory, metal, light alloy-based powders and other powders especially suitable for said processing pparations for which, due to peculiar, technical and technological, very significant features involved, an automatic preforming step is required in order to obtain a finished product as perfect as..possible wheil reducing to a very minimum essential any further operations for finishing the product or correcting defective pieces as is the case at present with corresponding productions using less improved methods than does this invention.
  • Said covering on the surfaces contacting the powdery substance to be pressed is in the form of a membrane or a skull-like cap made of synthetic elastomer or a metal powder based material to which plastic, high strength bonding agents are added.
  • the ceramic powder to be pressed is supplied through an adjustable volume batcher from which said material is deposited,in bulk,onto the concave membrane that will produce the profile of the rear, i.e. the foot side of a plate.
  • a shaped scraper approximately reproducing the profile of the visible side of a plate is caused to rotate axially above the material discharged from the batcher to spread it throughout the surface of the underlying shaped membrane so that said material is given said profile of the visible face of the piece to be pressed.
  • the rotary table is given a 90° rotation to bring the isostatio lower punch containing said preshaped aeramic material,to a position below the upper punch that is to form the visible face of the plate.
  • Said pressing punch is moved at a high speed, by an hydraulic jack, into contact with the material to be pressed, whereupon said punch continues its downwards stroke at a low speed to perform preoompression and deaeration of the material. Then, the above-mentioned jack is looked in said position in order to create opposition against hydraulic counterpressure from the lower isostatic punch thereby to achieve the final press- i n g operation.
  • the upper punch is moved back to its upper starting position and the rotary table is imparted a further 90 rotation to bring the pressed piece, that is still resting on the lower punch membrane, to a position belowa suction-cup arm that will move it away in a direction toward a deburring, trimming and sponging or moping unit associated with said press.
  • the press being a rotary table type of press, it is to be understood that each press station involves one specific operation of the press oyole corresponding to that station.
  • soup plates i.e. deeper plates than the former
  • things become complicated in that not in all cases is distribution of the powder to be pressed satisfactory due to the tendency of the dropping powder to collect in the middle of the bottom of the isostatio membrane,if the sides of a deep plate tend to be more vertical in shape than horizontal.
  • the shaped, centrally rotating scraper that provides for pre-shaping the powder to be pressed does not enable it to be, for ample, used for such square, oblong and, at any rate, irregular shapes, as are in general required for complementary pisces involved in the composition of commercial crockery sets.
  • An alternative press to the above discussed press which is the most wide-spread and accepted press at present for producing pressed crockery, is an horizontal axis type of press in which the powder is supplied and the pressed piece is discharged in a substantially vertical direction.
  • This press mounts dies provided with one or more recesses that are alignedon the same axis. Said recesses oan receive convex and stationary punches on the one hand and, on the other hand, concave punches that are movable since they are connected with the cross-slide of the press. Contour shapes and internal profiles of said convex and concave punches are substantially infinite in number and different from one another, and this even in one and the same die mounted in one of said horizontal presses.
  • the supply of the ceramic powder to be pressed takes place, as already said, by gravity in a vertically conveyed manner.
  • the arrangement is very simplified as compared with that of the previously described press, since both the volume batcher and the shaping scraper are dispensed with.
  • the die unit of said press comprises, as an example, a convex punch fast on the press struoture which reproduces the profile of the visible face of a plate; said stationary punch is located in a ring means that is firmly secured to the movable die of the press. Said movable die and,thus,said ring means, are provided with a central groove through which a powder to be pressed can flow.
  • the movable concave punch that is secured to the press cross-slide, reproduces the rear of a plate, i.e. the 'foot' side thereof
  • the working cycle takes place as follows:
  • said die-system produces considerable burrs that are to be removed from the pressed plate by further difficult operations which cause the produced pieces to undergo peripheral stresses with increased number of rejections being involved. ;
  • any broken pressed pieces tend to accumulate on the chute together with lost powder from the recesses in the die unit, all of which will sometimes hinder production to such a point that the line has to be stopped in order to clear the chute.
  • the pieces be let to drop onto the chute, and this is, for example, true with some types of bulky, very heavy oblong plates of which 20 + 30% will undergo cracking already at the press level.
  • Said horizontal press wheil being suitable for producing salad plates, is entirely unsuitable for the production of tea- and coffee-cups, which would collide with one. another while falling to the underlying chute to make for more and more rejections etc...
  • the invention which provides an hydraulic press of vertical axis, equipped with a rotary table or, as an alternative, a roundabout of movable punches which, in addition to perform their main function that is to form one face of a piece, also serve as the means for transporting the plates during the further steps provided by the automatic cycle of the press.
  • the powder to be pressed is supplied ⁇ through a known-system comprising a vacuum-motor pump by which powder is constantly delivered to a small bin arranged above the press.
  • Said bin is connected by one or more flexible pipes to a batching and preforming system according to the invention which acts directly on the movable punohes, these latter being, at each time, positioned axially below said preforming batoher.
  • the movable punches are moved to a position axially below a pressing unit which in addition to an hydraulic piston of adequate sizes, also includes a pressing punch for pressing the counter-faoe of poece, the punch being attached to the above-mentioned piston.
  • the movable punches are, again in succession, positioned under a suction-cup arm that will pick up a pressed plate to deposit it onto turn- plates associated to a finishing or trimming machine placed alongside the press.
  • the above-mentioned batching, preforming, pressing, discharg- ing and finishing operations are conducted simultaneously by the use of one or more die-units,depending on the different sizes, shapes and profiles of the pieces to be produced, by adequate setting up of the same press each time.
  • a feeder unit for supplying a powder to be pressed
  • 2 is a relay-bin with an associated control means 3 for constant level of a powder to be pressed
  • 4 is a flexible means connecting the relay-bin to the batohing and forming unit 5
  • 6 is a revolving table carrying the movable punohes 7
  • 56 is an electro-valve with a movable nozzle for blowing compressed air into the punch 7
  • 9 is an upper punch of the rigid, covered type or, as an alternative, the isostatio type, secured to the movable piston rod of a pressing piston 10, which bears against, and is rigidly connected to, a stationary, upper oross member 11
  • 12 is a press bedplate with, located therein, the uprights 13 that support the stationary oross member 11 to form, together therewith, the strong pressing structure
  • 14 is a controlled valve for rapid pre-filling and discharging of oil into and from the pressing piston 10 in cooperation with reservoirs 15 arranged on
  • the above unit essentially comprises a housing 8 inside which a counter-punch 27 is located, said counter-punch 27 having a profile that, unlike the oases known, does not correspond to that of the finished piece.
  • This profile will, in fact, be defined both on a preliminary study level and by subsequent pressing and backing operations carried out on it on a trial basis.
  • modifications may be made, for example, to a plate foot by the use of an increased or decreased amount of the powder concentrated at that point, by only working on the profile of the counter-punoh when, although the final profile and tick- ness having been respected, the plate foot would not show the same uniform density as is achieved everywhere on the remainder of the finished piece.
  • the movable punch 7 practically remains, in such cases, unchanged since, taking into account possible shrinkage and deformation of the pieces to be obtained, it must produce the required profile in a true manner.
  • Said counter-punch 27 is made of an elastic material having well defined properties which allow for compliance of a protrud- ing end 27' of said counter-punch when, during preforming and precompressing of the soft material firmly held between said counter-punch and the punch 7, said end 27' will be caused to bear, while being swollen, on the inclined peripheral plane of said punch under pushing effect of piston 65.
  • the above-mentioned counter-punch has through-holes 28 provided at given locations on its surface, which serve the main purpose of permitting the powder to be pressed to pass, at a predetermined time, from an upper chamber in housing 8 to a lower chamber that is defined, each time, by the counter-punch 27 together with a corresponding punch 7.
  • the looations, number and sizes of said holes 28 will vary according to the general shape, profile, thickness and sizes of what it is desired to press.
  • a metal e.g, stainless stsel support 29 is provided.
  • Said support which is also provided with holes formed therein in one and the same operation as the holes in the underlying counter-punch, is rigidly anchored to said counter-punch by having the elastic material of this latter directly molded on said support that has been previously treated so as to achieve high strength bonding together of the two parts. Therefore, the support 29 and the counter-punch 27 together form one integral body. This integral body is rigidly retained inside the housing 8 by the aid of screw means 30 which make for easy interchange or substitution thereof according to different requirements.
  • a movable plate 31 Placed over the support 29 is a movable plate 31 that serves the purpose of obturating the holes 28 during certain stages of the press cycle, such, for example, as that shown in fig. 2
  • Said obturator 31 is held in contact with the support 29 by means of a sliding block 32, for example, of teflon, that is acted upon by a spring means 33 secured to the end of a piston rod 34 associated to the forming and precompressing piston 65.
  • the obturator 31 is constantly acted upon and held in place by a spring means 35 and an associated tie bar 36 which is, in turn, firmly secured to the obturator 31 by the aid of a pin 37 such that, even in absence of electric power, an adequate closure of the holes 28 can be ensured.
  • Constant supply of the powder to be pressed is ensured, as mentioned herein before, by the combination of thefeeder means with associated bin means 2; the level control device 3 for safe control in case of absence of powder to be preased; one or more flexible pipes 4, figure 3, the corresponding ends 38 of which (figure 3) are rigidly connected with a flange 39 that is, in turn, rigidly secured to the piston rod 34 of piston 65.
  • the maximum level drops because of the powder moving down to the lower chamber from the upper chamber, the maximum level is automatically reset, without any particular control means being to be provided for, due to the flowing powder running by gravity.
  • Stopping of the press will also occur if, at an intermediate time between two cycles of the press, the flexible pipes 4 and rigid pipes 38 are not able to ensure timely reset of the maximum powder level in the upper chamber 8 due to an excessive and, thus, highar powder consumption, as a result of an excessively high production rate of the press. Therefore, the capacitive sensor 40 must always be positive in, responae, which means that minimum level is safely ensured.
  • a filter 4 is provided to ensure free air circulation inside the upper chamber of housing 8.
  • a diaphragm valve will be provided within said upper chamber to shut off the filter when very high pressure condition will require it.
  • figure 2 also shows,in its entirety,the batching and pre-forming system for the pieces to be preased, when in its rest position.
  • This unit is shown, by way of a non restrictive example, as being mechanically connected with the stationary upper cross-member 11 through a support means 43 that is provided, for example, with prismatic guides on which a carriage 45 can run or be positioned by means of a screw spindle 44, the carriage 45 being equipped with an appropriate threaded ring (not shown) cooperating with the screw spindle 44.
  • Screw means 46 and associated look nuts 47 permit the carriage 45 to be rigidly held in the position shown.
  • the entire batchin and preforming unit that is rigidly connected through the cylinder body 5 to the carriage 45 by means of screws 48 and cotter 49 can be made to occupy different positions,if this is necessary to suit different depths of new products.
  • the invention provides an electric valve having a movable nozzle 56, figure 1, which can admit compressed, properly calibrated air via a oonical aperture 50 and associated passages 51.
  • Said calibrated air blowing may be used under specific circumstances to cause aight inflation or swelling of the elastic membrane or skull-cover 52 (which is only peripherally bonded to the metal punch 7) in conjunction with the preforming and precompressing action exerted through the oounterpunch 27 corresponding to the concerned piece.
  • the punch 7 is centered on the revolving table by a pierced bushing 53; it is rigidly positioned by means of a conical pin 54 and rigidly fastened to the table by the aid of screws 55.
  • Figure 3 shows, in vertical sectional view, the batching and preforming unit with the housing 8 having been lowered onto the punch 7; the assembly being in the position that permits filling of the lower chamber and subsequent preforming and preoompressing operation.
  • Said figure 3 illustrates a modification in construction and operation of the movable punch 7' and certain auxiliary parts thereof.
  • said punch 7' comprises a metal base-plate having a rigid, skull-like covering 52' molded thereon, which is obtained from a high strength resin-bonded metal powder based material.
  • This punch 7' is particularly useful when production involves use to be made of ceramic powders containing about 1.5 % of M 2 O with chemical bonding agents added thereto.
  • said punch 7' is connected resiliently with the rotary table 6 through one or more assemblies 58 which comprise, as viewed in figure 3, a distance member attached to the punch 7', an antagonistie (or return) spring, and a screw means fitted to the punch 7' which permits the assembly, except for the spring, to be firmly secured to said punch.
  • assemblies 58 comprise, as viewed in figure 3, a distance member attached to the punch 7', an antagonistie (or return) spring, and a screw means fitted to the punch 7' which permits the assembly, except for the spring, to be firmly secured to said punch.
  • the punch 7' is centered on the revolving table by a taper pin 53'.
  • a further pair of cylindrical pine 57 secured to the punch 7' are arranged to be vertically slidable in a free manner in corresponding recesses provided in the rotary table 6.
  • a bellows means 59 is provided to prevent any foreign matter from having access to between the working surfaces of punch 7' and revolving table 6.
  • the above-desoribed arrangement permits use to be made of a mini-vibrator (not illustrated) which, by acting through the pins 57 at the time when the lower cavity is being filled, will assist in obtaining homogeneous distribution of the powder.thereby to achieve a still more improved quality of the product, if necessary.
  • FIG. 3 shows a pneumatic, diaphragm actuator 60 which under action of air pressure conveniently supplied to it through a passage 61, will cause movement of a hollow pin or spindle 62.
  • This hollow pin 62 is attaehed to the aetuator diaphragm and has a tie rod 63 passed therethrough which is, in turn, attached to the obturator 31 through a pin 64.
  • said actuator will cause, at the proper time, displacment of obturator 31 since it overrides the spring 35 and the associated tie members 36 that are themselves attached to obturator 31.
  • powder contained in the upper chamber of housing 8 commences to run through said holes and into the lower chamber that has formed between the convex surface of the underlying punch 7, or 7', and the counter-punch 27.
  • the filling depth of the soft matter which is the same as the preset distance between the opposing faces of punch 7, or 7 1 , and counter-punch 27, is dictated by the shaping piston 65 in cooperation with the annular piston 66.
  • Said charging depth of the soft matter will dictate the final thickness of a pressed plate.
  • Said position is, in fact, controlled by the down stroke that the double acting piston 65 is caused to perform through the piston rod 34 attached to the flange 39 which is, in turn, connected with the housing 8.
  • the invention has provided the annular piston 66.
  • This annular piston 66 has an adjusting ring 67 mounted on the lower threadedend thereof, which adjusting ring 67 is, in turn, provided all around its circumference, with spherical recesses into which a stop or looking pin 68 is caused to fit each time, this locking pin 68 being permanently urged against the adjust- ing ring 67 by a spring 69.
  • the maximum stroke of the annular piston 66 is bound, upwardly, by a bearing surface- formed in cylinder 5, and, downwardly, by the bearing surfaoe that is afforded by a guide means 70 attached to cylinder 5 through screw means 71.
  • chamber A is put under pressure while chamber B is simultaneously discharged. This causes instantaneous up-motion of the annular piston 66 which stops when the threaded ring 67 is striking against said guide.
  • a pivot 72 is provided. This pivot 72 is attached to the flange 39 and can slide in a bushing 73 that is, in turn, attached to a protruding portion of guide 70.
  • a magnetic sensor 74 is mounted on an associated adjustable support 75 and is designed to check, at each cycle, a constant position attained by the pivot 72 secured to flange 39.
  • housing 8 will take place under pushing action of piston 65.
  • the material to be pressed will take on, by compaction, the same shape as that of the profiles in intimate contact with which it is confined inside the lower chamber. There will occur, at this stage, a slight swelling up of the protruding peripheral portion 27' of counter- punch which,during the preceding step of filling up the lower ohamber, has provided the peripheral seal between the counter: punch and the underlying punch.
  • the actuator 60 and, thus, the obturator 31 are in the position shown in figure 3 in which the upper chamber and the lower chamber are kept communicating with one another through the holes 28.
  • this veryslight baokflow of the powder does not alter in any way the result aimed at in the lower chamber and ensures that the holes 28 should not be obstructed during precompressing of the underlying powder.
  • the diaphragm actuator 60 is caused to discharge through discharging passage 61 thereby to permit the spxing 33 to move the obturator 31 back to its rest position as shown in figure 2.
  • the time allowed for carrying out preforming and precompress ing of the powder is, in the actual practice, in excess of that required, since it is desired to make sure that the powder shall be precompressed with the same specific pressure, at each cycle.
  • a further electronic control is provided which is controlled by a magnetic sensor 76, adjacent to the sensor 74, to read the position of the pivot 72 when in its lowermost position as reached during the preoompressing stage. This position must, in the first place, be iterative during the various consecutive cycles, and whenever this should not happen, then the sensor 76 will give warning of it by stopping the press.
  • this sensor will stop the automatic cycle whenever the rod 72, connected with the housing 8, would move beyond the programmed lowermost position of the system as a whole. This would mean a not sufficient volume of powder having entered the lower chamber in spite of consent from all of the preceding electronic controls. It could also denote a partial obstruction of holes 28 or a loss of powder peripherally occurring at the protruding area 27' which does not provide for a thorough sealing there. Thus, this checking allows for determining in advance whether a preformed and precompressed part will be suitable for final pressing operation, thereby to avoid such damages to the upper and lower pressing punches as are experienced on known presses of the vertical or horizontal axis type.
  • stopping of the press sometimes occurs when it is to late so that the dies are damaged even if to a very small extent, which obviously requires stopping the production to replace the dies with all the troubles that are likely to be involved under such circumstances.
  • chamber A of cylinder 5 is put to discharge while at the same time chambers B and C are pressurized and cause the pistons and, thus, the parts connected therewith, to 'm o ve to the starting position for a next cycle.
  • the combination of the oounterpunch 27 and the feeding system utilizing the holes 28 to supply the powder therethrough according to this invention permits use to be made of dies of any shape, profile and size, obviously subject to the maximum tonnage of the vertical axis press used.
  • Figure 4 shows, on a true scale, in sectional view, a part of the housing 8, the counter-punch 27, the protrusion 27' when in its swollen condition due to the pushing action exerted during preoompression, and the lower punch 7 with its covering 52.
  • FIG 4 Also shown in figure 4 are, in particular, the thickness of the support 29 and the associated obturator 31 (both of stainless steel), and the holes 28 provided therein.
  • the chamber formed by the punch 7 and the counter-punch 27 is shown to contain a plate 77 at the time when preshaping and precompressing have taken place and, thus, before the housing 8 is raised, the holes 28 being already obturated.
  • the thickness ratio is about 1/1.4 while, in general, the soft to pressed ratio of the powdery atomized products ranges from 1/1.8 to 1/2.2.
  • the automatic pressing cycle comprises at least one first low pressure, slow pressing step for deaerating the powder contained in a soft state in their dies, and at least one further high pressure, rapid pressing step for final sintering of the pisce.
  • Said first pressing step for deaerating the powder which is essential in conventional presses, requiresthat, in the isostatie or not isostatic dies, considerable clearances be provided between the moving parts in order to allow air escaping.
  • the clearances significantly increase with the time due to the fact that escaping of air contained in the powder tends to draw along dust, often very abrasive in nature, which wears away the edgesof the generally hardened punches and the rings of the dies in which the punches slide.
  • the burrs are to be removed on automatic machines that are very complicated and expensive since they have to operate on crude and, thus, delicate pieces.
  • figure 5 is a 1:1 scale, partial sectional view, showing a pair of punches during final pressing of plate 19.
  • the upper punch 9, of the isostatic type, is attached to the piston rod of the pressing piston 10, figure 1.
  • Said punch includes a prefabricated, high pressure diaphragm or membrane 78 whose peripheral sealing is ensured by a ring 79 and the provision of close-set screw means 80 which fasten said ring to the upper punch 9 by firmly presaing the membrane edge in between.
  • the oiltight seal for the high pressure oil introduced, at the time of the final pressing step, through the passages 81, 82, 83, 84 provided in the upper punch 9, is ensured by the particular peripheral profile 85.
  • the threaded connection 86 ensures sealing of the end of the flexible pipe that is connected to said isostatic punch. Oil at high pressure is supplied, at the required time from a suitable motor pump unit or a pressure booster. Also shown in figure 5 is the chamber 87 that, during the pressing step shown, is filled up with high pressure oil.
  • the skull-like covering 52 and the membrane 78 have, at their respective peripheral zones, a radially extended end-portion corresponding to the edge of a pressed plate.
  • said two radially extended end- portions, the peripheral inclined plane of punch 7 and the opposing part of membrane 78 will be in contact with, and firmly compressed against one another, under high pressure exerted on the membrane, so that this latter is deformed on all points of its surface, including the above-mentioned portion.
  • no interspaoe exists between said two surfaces it is ensure that no burr in any form whatsoever is produced, according t the invention.
  • this invention has suppressed all of the scraping, finish or trimming operations that are to be carried out when plates are produced on presses of the prior art. Only a final wet moping, or sponging operate, ion will be required and is a simple operation useful in smoothing the edge of any type of plate, a part from the type of press or production involved.
  • the upper punch 9 In use, the upper punch 9 is moved down to a point above the preoompressed piece 77 so as to encompass it without being in contact therewith.
  • the membrane 78 wheil still adhering to the'steel of the punch 9, since still in a discharging stage at this time, is positioned by the pressing piston 10 (figure 1) at a few 10th distance to the piece 77 (foot side) to be pressed.
  • Said compression permits any residual air contained in the precompressed piece 77 to escape through the gap between the inclined peripheral plane of punch 7 and the facing surface of membrane 78. Thereafter, high pressure oil provided in the mean time by the pressure booster 16 (figure 1), is immediately admitted upon the low pressure oil acting on the membrane, and final pressing of the plate 19 is caused to occur instantaneously. Admission of high pressure produces further substantial deformation of membrane 78 and, thus, instantaneous suppression of the above-mentioned gap,which prevents any possible formation of burr.
  • An electronic manometer causes the final pressing of the plate to come to an end as soon as a preset pressure is reached.
  • the piston 10 and the upper punch 9 attached thereto are move back to their starting position thereby to release the plate 19 and the corresponding lower movable punch 7, these latter being then moved to a position beneath the revolving suction-cup arm which will bring the plate 19 to a trimming machine 21 (figure 1).
  • This mechanical transfer of the pressed piece from the movable punch 7 to the turnplate 20 of finishing machine 21 (figure 1) is carried out in the same manner as in conventional vertical presses for producing plates, that is to say in a manner that ensures protection of the pressed piece against such shocks and malfunctioning as are experienced on the discharging systems associated with the prior art horizontal presses, thi being achieved, by the present press, without any limitations as to the shape, profile or weight of the product obtained according to the invention.
  • the invention ensures still more protection, since, as already described, the pressed pieces 19 are conveyed to the finishing machine 21 substantially turned upside down, i.e. such as they are presseds a condition permitting them to be easy received on the respective turnplates 20, which latter have profiles and utilize mechanical arrangements equivalent to those of the movable punches 7 of the press according to the invention.
  • the arrangement of the individual punches is of primary and decisive importance for permitting extension of all of the above-described peculiarities and advantages of the invention from the range of the pressed plates to any of other alternative and complementary ranges of products without any restrictions as to the shape, profile and size of such products.
  • the invention offers the significant exclusive advantage that said alternative products are obtainable on one and the same vertical press, by the use of either single or multiple dies, with the only provision that the external sizes of said dies be such as to enable them to be introduced into the press.
  • figure 6 is a vertical sectional view showing a housing 8 t , a counterpunoh 27 , a support 29' and associated obturator 31' together with various complementary parts, a respective isostatic upper punch 9' and the corresponding movable semi- rigid lower punch 7', all of which are provided in relation to an ootagon-shaped vessel designated by numeral 77 1 and shown at the time when it has been preshaped and precompressed by the combined action of counterpunch 27" and skull-like covering 52', under aotion of air pressure supplied via the passages 51' that are in turn fed through the movable nozzle of the electric valve 56.
  • Figure 6 also shows the differences in internal and external profiles of the preshaped piece 77' with respect to the finished piece 1 9 '.
  • Figure 7 shows the just pressed plate 19 when it has been picked or Bucked-up by the suction-cup arm 18.
  • Said plate will then be deposited on a turnplate 20 of the finishing maohine 21 to be subjected to a wet sponging or moping operation, carried out by moping or sponging units 22.
  • both the punch 7 and the revolving table 6 are held locked in position by a proper locking system such, for example, as a cam system or of the Maltese cross type.
  • Figure 8 shows a subsequent stage where the punch 7 is positione beneath the piece charging and pre-shaping unit. Said unit is, obviously at rest in order to permit the lower movable punch 7 to be put in position.
  • Said rest position is achieved by the piston 65 whose upper chamber A is in a discharging condition while the lower chamber B+ of same piston 65 is under pressure.
  • Figure 8 also shows the annular piston 66 in its at-rest position in which it does not counteract the piston 65.
  • This condition is achieved by the existence of fluid pressure in chamber B+ and the absence of pressure exerted by the counter-face of said chamber C .
  • Powder contained in housing 8 cannot pass through the holes 28 because of the obturator 31 obturing said passages under traction exerted on it by spring 35.
  • This condition is ensured by the fact that the diaphragm actuator 60 is at rest since not being urged by fluid pressure via the passage 61.
  • the batching and pre-shaping unit is permitted to move down, as shown in figure 9.
  • the upper chamber A+ of piston 65 is shown to be under pressure, while the intermediate chamber is discharging via B.
  • the piston 65 is, therefore, in a low position, and this position is controlled by counter-action of the annular piston 66 which is urged by fluid pressure at inlet C+.
  • Said annular piston 66 is in turn controlled, in its upward stroke, by the adjusting, threaded ring 67 which is bearing against the bottom side of guide 70. As described previously, this position setsa limit to the downwardly adjustable stroke of piston 65 and, thus, of the housing 8 and the counterpunch 27 connected thereto.
  • the counterpunch 27 is at a predetermined distance to the movable lower punch. This corresponds to the volumetric filling depth of a powder to be preshaped and precompressed in the chamber that is defined by the counterpunch 27 and the lower punch 7.
  • the diaphragm actuator 60 When both the housing 8 and the counterpunch 27 are correctly positioned (as controlled and confirmed by appropriate sensor means), the diaphragm actuator 60 is operated through passage D+ and causes, against action of spring 35, displacement of the obturator 31 to bring the holes 28 in said obturator 31 to a position in which they are registering with the holes 28 in support plate 29 and with those in the counter-punoh 27,
  • powder commences to run from the upper chamber in housing 8 to the lower chamber formed, as already said, by the counter-punch 27 and the lower punch 7.
  • the precompressing step shown in figure 10 is started.
  • piston 65 is shown as being acted upon by fluid pressure in the upper chamber, through A+.
  • the lower chambers -that were counteracting, in cooperation with the annular piston 66, the further down- movement of piston 65- are caused to discharge via the .. passages B- and C-.
  • the actuator 60 is kept positive through the fluid pressure- f e d passage 61 in order that registration of the holes 28,which communicate the lower and upper chambers of housing 8 with one another, be ensured also during the pre-compressi l n of pieee 77.
  • said pre-oompression is performed by the piston 65 during its further down movement that is only counteracted, in this case, by the progressive increase in compaction of the povder enclosed in between the oounterpunch 27 and the movable punoh 7.
  • the amount of compaction is usually bound to the effect of the maximum (pre-regulated) fluid pressure working, at each cycle, on piston 65 in opposition to the counter-acting powder that is being preoompressed.
  • the diaphragm actuator is d.e energized whereupon the spring 35 causes the obturator 31 to move back to its rest position. When this position is attained, the obturator shuts off communication of holes 28 thus preventing the powder and air from flowing further to or from one chamber or the other respectively.
  • Resetting of the fluid pressure conditions at points A, B, C as shown in fig. 8, causes the oounter-punch 27 and the associated housing 8, to move back to the same high position as occupied at the start of the preceding cycle.
  • the revolving table Upon releasing of the punch 7 and the corresponding precompredsed plate 77, the revolving table is actuated to bring said lower movable punch and the piece resting thereon, to a position beneath the isostatic pressing punch 9 that is firmly retained in a self-aligned manner, by a magnetic surface 89 (figure 11), against the piston rod of piston 10.
  • the lower chamber in cylinder 90 is caused to discharge through passage E- which was, up to that time, in a positive state.
  • the valve 91 for fast pre-charging is opened and permits filling of the upper chamber of piston 10 until this latter is stopped at its lowermost preset point.
  • the pre-charging valve 91 is closed to permit fluid at the working pressure to be admittec through passage F and check valve 92 in order to apply a first compression on piece 77, through the piston 10 and the upper punch 9.
  • This operation allow for the air still remaining in the precompressed piece 77 to be entirely blown out through the peripheral gap that is purposely formed between the two punches, thus giving said piece a higher amount of compaction preparatory to the final pressing stage.
  • This final pressing stage may occur either through the piston 10 in cooperation with the pressure booster 16 and a semi-rigid upper punch, or, as an alternative, by means of the isostatic pressing punch 9, as shown in figure 12, in cooperation with both the piston 10 and the pressure booster 16 which generates the high pressure for said isostatic punoh 9, this latter being fed, at the pre set time, through passage G.
  • valve 91 is opened again while pressure fluid causes the piston 10, via the passage E and the lower chamber of said piston 10, to move back to its raised starting position.
  • said piston 10 will cause -through the magnetic surface 89- the pressing punch 9 to move up again, thereby to release both the plate 19 and the lower punch 7. Then, the revolving table will bring again the punch 7 along with the plate 19, to a position below the suction-cup 88, shown in figure 7, preparatory to the start of a next cycle.
  • the automatic cycle of this rotary table press 6 oomprises, for each upper pressing punch, at least two or three movable lower punches 7 which, depending on their respective positions, ensure execution of the different steps of the above-mentioned cycle in a simultaneous manner, so as to reduce the times of execution while speeding up production of this press to a maximum.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Press Drives And Press Lines (AREA)
EP85830252A 1985-10-08 1985-10-08 Presse pour l'obtention d'objets exigeant pour leur fabrication industrielle, une étape de préformage avec faible dépense d'effort, et une pression finale élevée Withdrawn EP0221224A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP85830252A EP0221224A1 (fr) 1985-10-08 1985-10-08 Presse pour l'obtention d'objets exigeant pour leur fabrication industrielle, une étape de préformage avec faible dépense d'effort, et une pression finale élevée

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP85830252A EP0221224A1 (fr) 1985-10-08 1985-10-08 Presse pour l'obtention d'objets exigeant pour leur fabrication industrielle, une étape de préformage avec faible dépense d'effort, et une pression finale élevée

Publications (1)

Publication Number Publication Date
EP0221224A1 true EP0221224A1 (fr) 1987-05-13

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EP85830252A Withdrawn EP0221224A1 (fr) 1985-10-08 1985-10-08 Presse pour l'obtention d'objets exigeant pour leur fabrication industrielle, une étape de préformage avec faible dépense d'effort, et une pression finale élevée

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EP (1) EP0221224A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0637489A1 (fr) * 1993-08-03 1995-02-08 Erich Netzsch GmbH & Co. Holding KG Outillage pour le pressage isostatique d'objets creux à parois fortement inclinées en matériau céramique
EP1270160A1 (fr) * 2001-06-26 2003-01-02 Kestro International Limited Méthode et dispositif pour la manufacture d'objets en céramique décorée en forme de plaque
WO2003028967A1 (fr) * 2001-10-01 2003-04-10 Decoraterre S.A.S. Di Mari Giuliano Ec. Presse, appareil de moulage et procede correspondant
EP1386704A2 (fr) * 2002-07-29 2004-02-04 Sacmi Molds & Dies S.p.A. Moyen de connexion hydraulique entre la matrice de pressage isostatique et le bloc
CN117000995A (zh) * 2023-08-09 2023-11-07 蓬莱市超硬复合材料有限公司 一种金属粉末加工用成型装置

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE194739C (fr) *
DE126374C (fr) *
DE441515C (de) * 1927-03-12 Paul Wernicke Vorrichtung zum Fuellen von Pressformen mit wenig plastischen Massen
US2409221A (en) * 1943-01-08 1946-10-15 Miller Pottery Engineering Co Puddling machine
FR63296E (fr) * 1952-09-15 1955-09-12 Procédé de fabrication de briques semi-perforées, et machine pour la mise en oeuvre de ce procédé
FR1402317A (fr) * 1963-07-17 1965-06-11 Machine circulaire, à moules multiples, formés de deux tampons pénétrant dans uncadre, pour la fabrication des carreaux de ciment, de céramique et produits similaires
DE1604492A1 (de) * 1966-03-30 1970-12-10 Dorst Keramikmaschb Inh Otto D Vorrichtung zum Pressen von pulverfoermigen bis koernigen Massen
DE2630355A1 (de) * 1976-07-06 1978-01-12 Netzsch Maschinenfabrik Presswerkzeug zum herstellen keramischer formlinge aus pulverfoermiger masse
GB2064417A (en) * 1979-12-04 1981-06-17 Laeis Werke Ag Press mould for moulding ceramic articles
FR2475971A1 (fr) * 1980-02-19 1981-08-21 Keramik Wtb Veb Procede et dispositif pour le moulage isostatique d'objets en ceramique

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE194739C (fr) *
DE126374C (fr) *
DE441515C (de) * 1927-03-12 Paul Wernicke Vorrichtung zum Fuellen von Pressformen mit wenig plastischen Massen
US2409221A (en) * 1943-01-08 1946-10-15 Miller Pottery Engineering Co Puddling machine
FR63296E (fr) * 1952-09-15 1955-09-12 Procédé de fabrication de briques semi-perforées, et machine pour la mise en oeuvre de ce procédé
FR1402317A (fr) * 1963-07-17 1965-06-11 Machine circulaire, à moules multiples, formés de deux tampons pénétrant dans uncadre, pour la fabrication des carreaux de ciment, de céramique et produits similaires
DE1604492A1 (de) * 1966-03-30 1970-12-10 Dorst Keramikmaschb Inh Otto D Vorrichtung zum Pressen von pulverfoermigen bis koernigen Massen
DE2630355A1 (de) * 1976-07-06 1978-01-12 Netzsch Maschinenfabrik Presswerkzeug zum herstellen keramischer formlinge aus pulverfoermiger masse
GB2064417A (en) * 1979-12-04 1981-06-17 Laeis Werke Ag Press mould for moulding ceramic articles
FR2475971A1 (fr) * 1980-02-19 1981-08-21 Keramik Wtb Veb Procede et dispositif pour le moulage isostatique d'objets en ceramique

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0637489A1 (fr) * 1993-08-03 1995-02-08 Erich Netzsch GmbH & Co. Holding KG Outillage pour le pressage isostatique d'objets creux à parois fortement inclinées en matériau céramique
EP1270160A1 (fr) * 2001-06-26 2003-01-02 Kestro International Limited Méthode et dispositif pour la manufacture d'objets en céramique décorée en forme de plaque
WO2003028967A1 (fr) * 2001-10-01 2003-04-10 Decoraterre S.A.S. Di Mari Giuliano Ec. Presse, appareil de moulage et procede correspondant
EP1386704A2 (fr) * 2002-07-29 2004-02-04 Sacmi Molds & Dies S.p.A. Moyen de connexion hydraulique entre la matrice de pressage isostatique et le bloc
EP1386704A3 (fr) * 2002-07-29 2005-08-31 Sacmi Molds & Dies S.p.A. Moyen de connexion hydraulique entre la matrice de pressage isostatique et le bloc
CN117000995A (zh) * 2023-08-09 2023-11-07 蓬莱市超硬复合材料有限公司 一种金属粉末加工用成型装置

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