HU209782B - Process and device for producing pressings from thermoplastic material - Google Patents

Abstract

A process for producing pressed members out of thermoplastic material by warming the thermoplastic, includes forming a blank using a ring shaped nozzle, directing a warm gas stream on the sepn. point, feeding the blank into a mould, closing the mould and applying pressure. The blank for the mould is located on an intermediate carrier, and the latter is lowered when the mould is closed.

Description

Scope of the description: 8 pages (including 2 sheets)

A fixed thermoplastic material is applied to a surface forming part of an intermediate holder (8) which is emitted under the press mouth (1) and is separated from the molding mouth (1) and recessed by closing the intermediate support (8). .

The apparatus of the present invention has an extruder suitable for the plastification of thermoplastic material and, optionally, a sealable compression die (1) for annular material batches, which is hot towards the separation site of the material portions from the molding mouth (1). it may be surrounded by a ring nozzle (4) suitable for discharging a directed gas stream. The apparatus further comprises at least one sealing mold comprising a molding stick (5) and a forming pin (13). The shaping sticker (5) is configured to coaxially coaxially lie under the squeegee (1) on the one hand and the forming piston (13) on the other. The apparatus is adapted to apply and maintain a pressing pressure on the molding mandrel (13) and / or the molding stick (5).

The device is characterized in that an intermediate holder (8) can be provided in the molding mat (5), the free surface (11) of which is in the inward position forming part of the molding surface (5) which defines the shape of the extruded body.

The present invention relates to a method of making extruded bodies from thermoplastic material, wherein the thermoplastic material is plasticized, optionally forming a semi-finished mold with an annular press, which is optionally separated by applying a hot gas stream to the separation site surrounding the die, the semiconductor is then pressed into the mold, sealed, the extruded body pressed by pressing pressure and at least partially under pressure of the extruded body. The invention also relates to an apparatus for carrying out a process comprising an extruder suitable for plasticizing a thermoplastic material, and a sealable press-fit mold, optionally in the form of a ring, for the release of material portions, which may, if necessary, be hot, from the material from the extrusion mouth. wherein the device further comprises at least one sealing mold comprising a molding mat and a forming mandrel, wherein the molding mat is arranged coaxially on one hand under the molding mouth and on the molding mandrel; and the apparatus is adapted to apply and maintain a press pressure on the molding mandrel and / or the molding stick.

This type of procedure is known from U.S. Patent No. 3,323,875. According to this solution, the thermoplastic material is emitted from an annular press mouth and is supplied to a press mouthpiece. The material is maintained in contact with the molding mouth.

The material adheres to the die-casting ballast, from which it must be pulled down later when closing the mold. As a result, before the semi-finished element cools down, it enters the pressing mold, and on the other hand, the pulling mechanism has problems with the operation of the scraper due to adhesion, since the thermoplastic material grabs the press-ballast.

A similar procedure is known from German Patent No. 30 23 415. In this solution, the semi-finished portions separated from the pressing mouth by its closure are released into the compression space with a free fall. In this way, the batches of material removed do not come into contact with the cooled surfaces of the mold during their downward movement. However, the semi-finished sections remain in the mold for a longer period of time, which is many times the time of the fall, so long as the die is removed from the die and the die stamped into the axial position. Thus, the semi-finished profiles have relatively large contact surfaces with the cooled shape, so that the plastic on these contact surfaces begins to cool down and no longer can be pressed well, at the expense of the quality of the extruded bodies produced. If the molding mouth and / or its closing body is not machined with maximum precision, or dirt is adhered to on these parts, the detachment of the semi-finished member does not occur exactly along the entire circumference, so that the semi-finished piece does not collapse precisely in the molding space itself, which itself, or in connection with the already exposed parts of the plastic mass on the cooled wall of the mold, it does not lead to the formation of extruded bodies, in other words, it results in scrap. The same negative effect can also be caused by the fact that the gas flow, which is applied to the place of separation of the semi-finished piece from the press mouth, is not uniformly applied to the semi-finished part, thus causing uneven separation of the semi-finished piece and, on the other hand, the semi-finished element from the axial. accelerates in different directions so that it cannot be centered in the molding space.

U.S. Patent Nos. 3,323,875 and 30,2415 and U.S. Patent Nos. 4,242,515 and 5,215,155 disclose devices for carrying out processes associated with the above-described problems.

U.S. Patent No. 2,403,948 discloses a method for producing buttons having a deep central hole. During production, a plastic particle is introduced into a two-part form, which is an ejector and a

EN 209 782 ét contains a centrally located form piece for the deep central hole. After sealing the mold, the plastic granule is melted and molded under pressure under pressure, and then, when the plastic granule is completely melted, the mold is removed. The melt is then cooled, and if the cooling has occurred sufficiently, the mold is withdrawn, the mold is opened, and the key containing the hole is removed from the mold by means of the ejector.

U.S. Pat. No. 3,256,378 relates to an apparatus for producing a tube head and simultaneously connecting it to a tube tube. During this operation, the plastic is passed through a nozzle into a cavity of a mold and then pressed into the tube head by introducing a crimping stamp bearing the crude tubular body while establishing a connection with the tube tube. According to this solution, the plastic mass is led from the bottom into the cavity of the mold, where the mass remains until the mold is sealed and thus cools, which is of course a disadvantage.

It is an object of the present invention to improve the method and apparatus defined in the preamble to such a degree that the contact of the semi-finished parts with the cooled mold is limited to a minimum.

According to the present invention, the object of the present invention is to provide a method of plasticizing a thermoplastic material, forming a semi-finished element with an annular pressing mouth, which is, if necessary, separated by a hot gas stream directed to the separation site and surrounding the die. the semiconductor is passed into a compression mold, sealed, the extruded body formed by extrusion pressure and at least partially under pressure pressure of the extruded body, and characterized by an intermediate plasticized thermoplastic material required for a semi-finished piece by an intermediate pressed under the press mouth. attaching the holder to the part of the die forming part of the die and separating it from the pressing mouth; and lowering the intermediate support when the die is closed.

By placing the plasticized thermoplastic material exiting the extrusion mouth on a portion of the intermediate holder that is emitted under the molding mouth, on the one hand, the short path is precisely guided and thus centralized material release so that uneven detachment or possible contamination in the perimeter region can have no influence on the semi-finished part situation. This finding is also valid with respect to the effect of the ring-shaped gas flow that may be used. The semi-finished piece lies on only a part of the mold, so there is no effect on the quality of the pressed bodies in the cooling down there. By holding the intermediate holder in the outward position, the semi-finished member is flushed around each side of the hot surface with the exception of its contact surface, so that the semi-finished member will come into contact with the larger portion of the cooled mold only when the actual extrusion process begins.

By the fact that it is only slightly cooled from the moment of production of the semi-finished element to the pressing of the semi-finished mold and practically only in those places which no longer need to be moved when the final shape is given, the plasticized plastic temperature may be lower than in the known similar-purpose processes, which, on the one hand, results in energy savings in the preparation of the plasticized material, accelerates hardening. Thanks to these factors, the invention results in energy savings and significantly accelerates the manufacturing process.

In a preferred embodiment of the method, the semi-finished member is placed on the surface of the intermediate holder so that the semi-finished portion extends outwardly from its periphery. Thus, the contact surface of the semi-finished member further decreases with the intermediate holder, so that it can still cool less.

The present invention relates to an extruder suitable for the plastification of thermoplastic material and, optionally, an annular sealable compression die for the release of material portions, which is a gas stream directed to the site of separation of the material portions from the molding, optionally plasticized. emitting, optionally ring-like, molding, and further comprising at least one sealing mold having a molding mat and molding pin, wherein the molding die is arranged coaxially on the one hand under the molding mouth and on the molding mandrel, and the apparatus on the molding mandrel and / or is designed to apply and maintain a press pressure on the molding stick and is characterized in that an intermediate holder capable of being extruded in the molding stick is provided, which is free its surface is in the inward position (in its initial position) forming part of the molding surface of the molding die, which defines the shape of the pressed body.

According to a preferred embodiment, there is a coaxially arranged and axially retractable rod in the intermediate holder. It may also be advantageous if the surface has elevation in the peripheral region.

Since the surface of the intermediate holder is part of the extrusion mold giving the final shape of the extruded body, the slight cooling of the semi-finished member in the contact region is not disadvantageous, since the plastic is not required to be removed from this central region during the actual stamping operation.

The invention will now be described in more detail with reference to the accompanying drawings, in which a preferred embodiment of a device for producing headers for tubes can be attached to the head to be produced simultaneously with the manufacturing operation. In the drawings, FIG. 1 is a schematic cross-sectional view of an open molding mouthpiece for emitting a thermoplastic material and an intermediate molding.

EN 209 782 Β is a part of a mold of a mold;

Fig. 2 shows the parts of the apparatus of Fig. 1, but the press mouth is in the closed state;

Fig. 3 is a schematic sectional view of the molding stick shown in Figs. 1 and 2 to which the molding mandrel fits;

Fig. 4 shows the parts of the apparatus of Fig. 3, but the molding stick and molding mandrel are in the pressing position.

Figures 1 and 2 illustrate a compression die 1 for dispensing (dispensing) a thermoplastic material from an extruder for plasticizing plastics material. The press mouth 1 has a closure body 2, by means of which a desired amount of annular semi-finished mold 3 can be provided. The extrusion opening of the press mouth 1 is surrounded by a 4-ring nozzle. For example, the annular nozzle 4 can be supplied with hot air which, when closing the closure body 2 of the press mouth 1, can facilitate the separation of the semi-finished member 3, and the annular nozzle may also serve to flush the semi-finished member 3 held in its position by the hot air, and thereby the semi-finished member. protects it from cooling down.

The die 5 is arranged axially relative to the molding mouth 1 which forms part of a mold for producing a tube head 6 (FIG. 4). The interior of the molding stick 5 is configured to correspond to the outer shape of the tube head 6 to be manufactured. The mold 5 is generally of multi-part design and has a portion 7 which is provided for the threaded neck of the tube head 6. An intermediate holder 8 is arranged centrally and axially in the mold matrix 5; the displacement is possible between the lower and upper 9, 10 bumps (shoulders). In the upper end bounded by the stop 9, the intermediate holder is positioned at a distance from the molding mouth 1 so that the material leaving the molding mouth 1 lies directly on the surface 11 of the intermediate support 8. The distance between the surface 11 and the press mouth 1 must be chosen so that the required amount of material is just in place.

However, it is also possible to place the surface 11 of the intermediate support 8 directly below the press mouth 1, and to lower the intermediate support 8 in accordance with the amount of material released.

Inside the intermediate holder 8, a central and coaxially extendable rod 12 extends over the surface 11 of the intermediate support 8 and serves to center the annular cross-sectional plastic stream 1 of the molded part 3, on the one hand, and 6 on the other hand. keeps its outlet open when the tube head is pressed.

The intermediate bracket 8 and the rod 12 can be pushed and unloaded by any means known in the art (not shown), for example by spring force, hydraulically or pneumatically.

The surface 12 may be flat or adapted to the shape required to form the tube head.

Preferably, the surface 11 of the intermediate support 8 may be concave or plate-shaped or may have a raised rim (see Figures 1-4). The surface 11 in the base position of the intermediate holder 8 (see FIG. 4) forms part of the forming mat 5 which is the outer boundary surface of the outlet of the tube head 6.

Figure 3 is a bottom end of a forming mandrel 13. The molding mandrel 13 has a sleeve 15 for supporting the tubular body 14, in which a tool stamp 16 (squeezing stamp) for the inner shape of the tube head 6 is axially movable, movable relative to the sleeve 19.

With the apparatus described above, the process is accomplished as follows:

Example 1: a mold mat 5 is placed below the extrusion die 1 of the (not shown) extruder. Following the opening of the closure body 2 of the press mouth 1, a plasticized, annular cross-sectional thermoplastic stream flows out of the opening of the press mouth and, in the open position of the press mouth 1, rests on the surface 11 of the intermediate holder 8. The press mouth 1 remains open until the required amount of material has passed through; this portion of material, preferably free, must extend beyond the rim of the surface 11 of the intermediate support 8. While the molding mouth 1 is open, the rod 12 in the intermediate holder 8 is in contact with the closure body 2 of the molding mouth 1, whereby the plastic exiting the tubular shape is guided inside and centered. By closing the closing body 2, the further plastic flow (current) is interrupted - optionally, the hot gas flow leaving the annular nozzle 4 also facilitates the execution of this operation, and an annular semi-finished element 3 is selected which, as shown in FIG. Figure 11 shows the edges extending over the surface. It is also apparent from Figure 2 that, compared to the total weight of the semi-finished member 3, there is only a small contact area with the intermediate holder 8 or the rod 12, so that no significant cooling can occur, especially not only because - unlike the styling stick 5 - neither the rod 12 nor the intermediate holder 8 is directly cooled (the refrigeration system of the molding stick known per se for faster cooling is not shown in the figures). The low cooling at the contact points is not only tolerable, but also has to be considered positive, since the contact points during the actual pressing process are practically not or hardly to be moved so that the high mobility of the plastic at these locations is not required.

As a result of the air sealing applied to the cooled molding sticker, this sticker can practically not transfer the cooling effect to the 3 semi-finished parts. If hot air is emitted from the annular nozzle 4, the semiconductor 3 is flushed and can be maintained at the desired temperature by controlling the air temperature, i.e., optionally heated. In the upper position, keep the 3 semi-finished sections until the 5th

The formatting sticker 209 782 Β does not come into coaxial position with the molding mandrel 13. Since the molding pads 5 are generally arranged in a rotary table, the molding coat can be brought to said coaxial position via one or more stroke steps, without having to keep the semiconductor 3 from cooling down, which is forced to occur when a semi-finished element 3 is directly transferred from the molding to the cooled mouth. formázómatricába. When setting the molding mandrel A13 (see Fig. 3), i.e. when the tool punch 16 (mandrel) comes into contact with the upper end of the rod 12, by further lowering the molding mandrel 13, the intermediate holder 8 also moves downward with the rod 12 to the lower stop 10. Meanwhile, the sleeve 15 also enters the projected position of the mold 5 within the mold 5, and only the lower tool stamp enters the die 5 within the sleeve 15 while the pressure is exerted, and the rod 12 is in the position shown in FIG. while the formation of the final form of the 6 tubular heads and its connection (union) with the tubular body occurs. In this position, the tool stamp 16 is kept under pressure until the time required for cooling. It is of course also possible to move the molding stick only relative to a stationary molding mandrel or vice versa; and it is also possible for both the forming mandrel and the sticker to move relative to one another.

Claims (5)

PATENT CLAIMS A process for making extruded bodies from a thermoplastic material by plasticizing the thermoplastic material, optionally annularly forming a mold to form a semi-finished mold, optionally using a hot stream of gas surrounding the extrusion mouth, then inserting the semi-finished mold into a die, sealing it by pressing the die body and cooling the die body at least partially under pressure, characterized in that the total amount of plasticized thermoplastic material required for one semi-finished die is (1) transferring the intermediate support (8) to a surface forming part of the die and separating it from the die (1); and lowering the intermediate support (8) when the mold is closed. Method according to Claim 1, characterized in that the semi-finished piece is placed on the surface of the intermediate support (8) so that the semi-finished piece extends outwardly from its periphery. 3. Apparatus for the production of extruded bodies from thermoplastic material having an extruder suitable for plasticizing the thermoplastic material and optionally annular lockable extruding mouth (1) for release of material portions, optionally plasticized a nozzle (4), optionally annular, for discharging a gas stream directed at its separation point from the extrusion die (1), further comprising at least one lockable extrusion die (5) and a forming mandrel (13), 5) formed on the one hand under the press die (1) and coaxially with the forming mandrel (13), and the device is adapted to exert and maintain an extrusion pressure on the forming mandrel (13) and / or the forming die (5), characterized in that formázómatr In the barrel (5) there is provided a removable intermediate support (8), the free surface (11) of which, when retracted, forms part of the forming surface of the forming die (5) which defines the shape of the extruded body. Apparatus according to claim 3, characterized in that the intermediate support (8) has a rod coaxially arranged therewith and which can be axially released. Device according to claim 3 or 4, characterized in that the surface (11) has an elevation in the circumferential region.