AT506007B1 - METHOD AND DEVICE FOR PRODUCING MULTICOMPUNUSED PLASTIC FORM PARTS - Google Patents

Abstract

A method for producing multi-component plastic molded parts by means of turntable or Indexplattentechnik, wherein by means of a turntable (7) or an index plate several stations (1, 2, 3) are approached, wherein in a first station (1) a pre-molded part of a first particular thermoplastic component is produced, to which in a subsequent station (2, 3) a further component, in particular PUR material is attached. The invention is characterized in that the preforms produced in the first station (1) are alternately provided in one of two subsequent stations (2, 3) with the further component, while simultaneously in the other of the following stations (2, 3) a pretreatment of the empty cavity (A1, B2) takes place. Characterized in that by means of turntable or Indexplattentechnik worked and three stations (1, 2, 3) are provided, but only in two stations (1, 2, 3) a component of the molding is introduced, can simultaneously in the unused station ( 2, 3), a pretreatment of the empty cavity (A1, B2) take place while, as usual, the finished plastic molded part can be produced within two cycles, so that as a result no productivity loss occurs.

Description

Ss & Tschkschschpstwtaroi AT 506 007 B1 2013-01-15

Description: The invention relates to a method for producing multicomponent plastic molded parts, in particular plastic molded parts from a first thermoplastic component as a pre-molded part and a second component from a PUR material. The invention further relates to a suitable device for carrying out the method.

It is known to produce multi-component plastic molded parts in such a way that produced in a first cavity in a first cycle, a pre-molded part of a first component and then brought with a rotating tool in a second position, where a second cavity formed and the second component is molded onto this pre-molded part. The individual components may consist of different thermoplastic materials and optionally also have different colors. Likewise, certain components may be provided with fillers. Instead of thermoplastic components and polyurethane components can be provided, whereby the production of multi-component plastic molded parts from a thermoplastic component and a polyurethane component is known, the mold for equipping with the polyurethane component usually before foaming with a release agent is equipped (EP 1 810 811 A1, DE 10 200 601 9007 B3 and DE 10 200 601 6200 A1).

In the prospectus "multinject - injection molding machines for multi-color and multi-component technology". Krauss-Maffei Kunststofftechnik GmbH, 1st edition 5/97, there is a representation of usable in multi-component injection molding tooling techniques, being distinguished between non-rotating and rotating tools. With regard to the rotating tooling techniques, the turntable technique, also called turntable technique, and the index plate technique are mentioned and illustrated schematically.

From DE 196 50 854 C1 discloses a method and an apparatus for producing multi-component plastic molded parts by means of turntable technology, wherein a plastic injection-molded part is coated with at least one layer of a 2-component thermosetting plastic and the two Components are injected one after the other synchronously in the same mold. For this purpose, a base plate is used, which carries two identical, juxtaposed mold halves, and which is rotatably mounted about a horizontal machine longitudinal axis. The mold halves are fitted with dies from an injection molding machine and a RIM device. After injection of thermoplastic with an injection molding machine, the base plate is rotated by 180 ° about the horizontal machine axis and injected in the following cycle on the one hand a new thermoplastic part and on the other hand coated the thermoplastic part of the first cycle with the 2-component thermosetting plastic.

In the article "High quality premium surfaces of injection molding and reaction technology". in the journal "Kunststoffe", issue 10/2004, pages 180-182, a further method is described how multi-component plastic molded parts can be produced from a first thermoplastic component and a second polyurethane component. On the fixed side of a closing unit of a per se known injection molding machine is the station for the injection of the thermoplastic material and on the movable side is at the local mold half of the mixing head of a RIM device (Reaction Injection Molding) for PUR- Component docked. RIM devices are known per se and essentially comprise conveying and metering devices for the individual chemicals to be processed, such as polyol, polyisocyanate and possible additives (colorants, foaming agents, etc.). On the fixed side of the closing unit, a fixed mold half slide table is provided to move it from the "injection molding" position. into the position "PUR pour"; to proceed and vice versa. In the tool position "Injection Molding " a carrier is pre-molded from a polyamide plastic. At the end of the cooling time the tool opens and the sliding table moves to the position "PUR pour". After closing the mold, the PUR casting skin is injected into the larger mold cavity via the mixing head connected to a RIM mixing and dosing unit. 1/15

[0006] WO 03/013824 A1 discloses the production of multi-component plastic molded parts by means of the so-called turning plate technique. Here, between two outer platens a middle and about a vertical axis rotatable mold carrier (insert) is arranged, which may be plate or cubic. To the mold platens injection units for the production of multi-component injection molded parts or RIM devices for PUR materials, e.g. PUR foamers, be coupled. Likewise, a mixed assembly can be provided, in which a preform made of a thermoplastic is injected from an injection unit and coated with a layer of the PUR material in the RIM process or vice versa.

In the production of multi-component plastic molded parts, a pretreatment of mold halves can be useful. This is especially true in the production of plastic moldings from a thermoplastic pre-molded part, which is to be coated with a PUR layer. Before inserting the PUR material into the cavity, we recommend spraying the PUR mold half with a release agent so that the finished molded part can be more easily removed from the PUR mold half. In this case, one speaks of the separation of the PUR mold half.

Proceeding from this, the present invention seeks to provide a method and an apparatus that allows a pretreatment of mold halves without significantly affecting the productivity, in particular the separation of a PUR mold half.

The solution of this object is achieved by a method having the features of claim 1 and with devices having the features of the independent claims 8 and 9. The fact that works by means of turntable or index plate technology and three stations are provided, but only in two Stations a component of the molding is introduced, a pretreatment of the empty cavity can be carried out simultaneously in the unused station, while as usual within two cycles the finished plastic mold can be made eil, so that in the result so no loss of productivity occurs.

In particular, in the production of a plastic molded part of a thermoplastic component as a preform and an attached PUR layer or PUR-skin, hereinafter also called PUR thermoplastic composite component, in a thermoplastic injection molding station in the first cycle always a preform are produced, which is flooded in the second cycle in one of two PUR stations with the PUR material, while in the free, ie unused, PUR station, a pretreatment of the PUR form or the PUR mold half can be done, in particular the introduction of a release agent. The introduction of the PUR material can be done in a conventional manner via mixing heads, which are supplied by a RIM device. The starting of the individual stations can be done by means of known Drehteller- or Indexplattentechnik.

The invention will be described in more detail with reference to an embodiment and with reference to the figures. In the drawings: Fig. 1 injection molding machine with RIM device; Fig.2 View from the direction of the movable platen on the fixed

Platen in the open state of the clamping unit with the first embodiment of the PUR supply; Figure 3 view from the direction of the movable platen on the fixed platen in the open state of the clamping unit with the second embodiment of the PUR supply; FIG. 4 shows a plan view of the closing unit in the opened state; FIG. 5 view from the direction of the fixed platen on the movable

Mold clamping plate in cycle 1; Figure 6 is a plan view of the closing unit in the closed state with position of the mold halves as in Figure 2 or 3 together with Figure 5 (clock 1). [0018] Austrian AT506 007 B1 2013-01-15 FIG. 7 View from the direction of the fixed platen on the movable platen

Mold clamping plate in cycle 2; 8 plan view of the closing unit in the closed state with position of

Mold halves as in Figure 2 or 3 together with Figure 7 (clock 2); 9 Schematic representation of the procedure.

1 shows a known per se injection molding machine 30 with a machine bed 31, an injection unit 9, a clamping unit 33 and a controller 34. The clamping unit 33 has a fixed Formaufspannpaltte (FWAP) 5 for fixing the fixed mold halves 4 and a movable Form platen (BWAP) 6 with a turntable 7 for receiving the movable mold halves 8 and a release means device on. Between the mold platens extend columns 10 for receiving the closing force. This injection molding machine is associated with a RIM device or PUR system 15, comprising material containers 22 for polyol and isocyanate, a pump system 20, media lines 21a and 21b (one each for polyol and one for isocyanate) and a mixing head 23. In the here shown Example, the mixing head 23 is docked from above to the mold half 4; but it can also be docked in other positions, for example laterally or from below.

2 shows a view of the fixed platen 5 in the open state of the clamping unit 33. In the stationary mold half 4 are a forming station 1 for the preform and two mold stations 2 and 3 for the introduction of the polyurethane component. These forming stations are also referred to below as PUR forming stations. The mixing head 23 is mounted in the lower part of the fixed mold half 4. The PUR mixture can be introduced alternately into the PUR forming stations 2 and 3 via a PU gate distributor 24 and alternately operable sealing nozzles 25 and 26. As can be seen from FIG. 3, each PUR molding station 2, 3 can also be assigned its own mixing head 23, 28, wherein each mixing head is fed alternately via a switching unit 27 and media lines 21a, 21b and 29a, 29b to the PUR starting materials.

In the figure 4, the closing unit 33 is shown from above in the open state. In the fixed mold half 4, the forming stations 1,2 and 3 are arranged and the mixing head 23 is docked from below to the two PUR-forming stations 2 and 3 and therefore not visible in the figure 4. On the rotary mold 7 located on the movable mold half 8, two mold stations A and B and a separating means C are attached. In the state shown here is in the forming station A, a preform 11, for example made of a thermoplastic material, and in the forming station B provided with a PUR layer finished PUR thermoplastic composite component 12. During operation of the device, the closer below is explained, are located on the forming stations A and B in the change once-as shown here - the pre-molded part 11 in A and the composite component 12 in B, and once the pre-molded part 11 in B and the composite component 12 in A.

The operation of this device will be described below with reference to Figures 5 to 9 in more detail. First, the forming stations are moved together in the position as shown in the line I of FIG. 9, and cavities A1 and B2 are formed, while the separating means device C is assigned to the PUR forming station 3. This position of the forming stations is shown in FIG. 5 with a view to the movable mold half 6 immediately before the approach. FIG. 6 shows the situation in the closed state with a view from above onto the closing unit 33. A plastic melt for producing a preform, for example of a thermoplastic material, is now injected into the cavity A1. The cavity B2 initially remains unused and in the PU molding station 3, a release agent 13 is sprayed by means of the release agent device C. Subsequently, the forming stations are moved apart and the turntable 7 is rotated by 120 ° clockwise, the preform 11 remains in the forming station A; the position then assumed is shown in line II of FIG. FIG. 7 shows this situation with regard to the movable platen 6. After the forming stations have been brought together again in this state, cavities B1 and A3 are formed, while the separating means device C is now formed by the Asterisk es & AT506 007B1 2013 -01-15 more is assigned to the PUR forming station 2. This situation is shown in FIG. 8 as a top view of the closing unit 33. The next pre-molded part can now be produced in the cavity B1, while the pre-molded part from the previous cycle is simultaneously flooded with the PUR material in the cavity A3 and the release agent 13 can be sprayed in the PUR-forming station 2. Subsequently, the mold halves are moved apart again and the turntable is rotated by 120 ° in the counterclockwise direction, wherein the pre-molded part remains in the forming station B; this position is shown in line III of FIG. The finished molding located in the forming station A can be ejected before or after turning the turntable or removed by means of a robot. Now, the state of line I of Figure 9 is reached again, with the difference that in the forming station B already exists a pre-molded part. If now the mold halves are closed again, cavities A1 and B2 are formed and the separating means device C is assigned to the PUR forming station 3. A new pre-molded part is now produced in the cavity A1, the preform located in B2 is flooded with PUR material and C is used to cut the PUR forming station 3. After opening the forming stations, B can be a further finished PUR-thermoplastic composite component 12 ejected as a molding or removed (before or after rotation of the turntable 7). This situation corresponds to the illustration in FIG. 4 (before the rotation of the turntable 7). After another clockwise rotation of 120 °, the state of line II in Fig. 9 is again reached, i. it can cavities B1 and A3 are formed and the PUR-forming station 2 is associated with the separating means device C. This state is shown in line IV of FIG.

Instead of the rotary table technique described here can also be worked by means of the so-called index plate technology, as is known for example from the aforementioned prospectus. This is a tool with an integral rotating plate that can perform both axial and rotational movement. In this case, not the mold halves are rotated and fed in the above-described order, but the preform produced in the injection mold is moved out with the index plate from the injection mold half and alternately converted into one of two PUR forming stations. While the pre-molded part is flooded with the PU material in the PUR molding station equipped with the pre-molded part, a separation takes place simultaneously in the empty PUR cavity. Also simultaneously in the Spritzgießfom the next pre-molded part can be produced, which is subsequently implemented in the previously separated PUR molding station. The sequence of the method steps is as described above in connection with the rotary table technique.

The molding stations described above can be designed in many ways; In particular, they may be such that more than one cavity is formed in the closed state, so that, for example, in clock cycle 1 several preforms simultaneously produced and in clock 2, the plurality of pre-molded parts can be provided simultaneously with the PUR material. The mold stations each located on a plate of the injection molding machine can either be summarized in a mold half or executed as a separate mold halves. Likewise, these forming stations can be designed as inserts in a trunk mold half.

1. A process for producing multicomponent plastic molded parts by means of turntable or index plate technology, wherein by means of a turntable or an index plate several stations are approached, wherein in a first station a pre-molded part is made from a first component to which in a subsequent station another Component is attached, characterized in that two subsequent stations are used for attaching the further component, wherein alternately in one of the two subsequent stations to the preform the 4/15

Claims (14)

Austrian AT 506 007 B1 2013-01-15 additional component is applied while simultaneously in the other of the two subsequent stations, a pretreatment of an empty cavity or an empty mold half takes place. 2. The method according to claim 1, characterized in that as a further component, a PUR material is used. 3. The method according to claim 1 or 2, characterized in that as a pre-treatment, a release agent is introduced into the empty cavity or the empty mold half. 4. The method according to any one of the preceding claims, characterized in that as an IMC (in-mold coating) coating is introduced into the empty cavity or in the empty mold half. 5. The method according to any one of the preceding claims, characterized in that inserts are introduced as a pre-treatment in the empty cavity or in the empty mold half. 6. The method according to any one of claims 1 to 5, characterized in that on one of the platens of an injection molding an Spritzgießformstation (1) for the first station and each PUR-forming station (2, 3) are used for the two subsequent stations and that on the other platen two injection molding stations (A, B) and a pretreatment device (C) are used, wherein the forming stations (A, B) on one of the platens by means of a turntable (7) in succession with the forming stations (1, 2, 3) the other platen are brought together, that always a mold for producing a preform and a mold for introducing the PUR material are formed, while leaving free of the PUR forming stations (2, 3) for the pretreatment. 7. The method according to any one of claims 1 to 5, characterized in that on one of the platens of an injection molding an Spritzgießformstation (1) for the first station and each PUR-forming station (2, 3) are used for the two subsequent stations, and in that two injection molding stations (A, B) and a pretreatment device (C) are used on the other platen, the preforms being successively converted into the PUR molding stations (2, 3) by means of an index plate such that they always have a mold for producing a preform and forming a mold for introducing the PUR material while leaving one of the PUR forming stations (2, 3) free for pretreatment. 8. Apparatus for carrying out the method according to one of claims 1 to 6, with a fixed (5) and a movable (6) Platen and with a plurality of forming stations (1,2, 3, A, B) and with a turntable (7) , characterized in that on one of the platens (5) an injection molding station (1) and two PUR molding stations (2, 3) are provided and that on the other platen (6) of the turntable (7) is arranged and two forming stations (A , B), wherein the forming stations (A, B) on the turntable (7) by rotation of the same so successively with the forming stations (1,2, 3) on the one mold mounting plate (5) can be brought together that always a cavity for Production of a preform (11) and a cavity for introducing the PUR material are formed while one of the PUR forming stations (2, 3) for a pretreatment (13) is ready. 5.15 SUBWASH «jistestas't AT506 007B1 2013-01-15 9. Apparatus for carrying out the method according to any one of claims 1 to 5 and 7, with a fixed and a movable platen, and with a plurality of mold stations and with an index plate, characterized in that on one of the mold platens an injection mold (1) and two PUR Forming stations (2, 3) are provided, and that on the other platen two Spritzgießformstationen (A, B) are provided, that a movable in the machine longitudinal direction and rotatable about the machine longitudinal axis index plate is provided, and that the mold halves are arranged on both mold platens such in that the preforms can be successively transferred from the injection molding station to the PUR forming stations by means of the index plate in such a way that always a mold for producing a preform and a mold for introducing the PUR material are formed while one of the PUR forming stations for a pretreatment bereitste ht. 10. Apparatus according to claim 8 or 9, characterized in that on the platen with the two injection mold stations (A, B), a pretreatment device (C) is provided. 11. Device according to one of claims 8 to 10, characterized in that at each PUR-forming station (2, 3) connected to a RIM device (15) mixing head (23, 28) is provided or to these forming stations (2, 3) can be docked. 12. Device according to one of claims 8 to 10, characterized in that a with a RIM device (15) connected mixing head (23) is provided that at the mixing head (23) with the PUR forming stations (2, 3) connected or connectable PU gate distributor (24) and two closure nozzles (25, 26) are provided, each PUR-forming station (2, 3) is associated with a closure nozzle. 13. Device according to one of claims 8 to 12, characterized in that on the turntable (7) or the index plate, a release means device (C) with a nozzle for spraying a release agent (13) is provided. 14. Device according to one of claims 8 to 10, characterized in that with a RIM device (15) connected mixing head (23) is provided that at the mixing head (23) with the PUR forming stations (2, 3) connected or connectable PU Gußverteiler (24) and a further closure nozzle is provided, which combines the functions of the closure nozzles (25, 26) in one unit for this 9-sheet drawings 6/15