Injection molding method and injection molding device for producing a plastic molded part with a hole, and such a plastic molded part

Abstract

An injection molding method for producing a single- or multi-component plastic molded part with a hole in at least one plastic component of the plastic molded part comprises the steps of: bringing two mold plates of an injection molding device closer together, wherein a cavity is formed between the mold plates, which cavity comprises a cavity region for hole creation and a cavity region surrounding this cavity region for creating the plastic component of the single- or multi-component plastic molded part. A plastic compound is injected into the cavity by means of a plastic feed that opens into the cavity region for hole creation. While the plastic compound is still in a plastic state, at least one of the two mold plates is moved towards the other mold plate, wherein the plate movement essentially separates the cavity region for hole creation and the cavity region for creating the first plastic component.

Description

The invention relates to an injection molding method for producing a one- or multicomponent plastic molded part having a hole at least in a plastic component of the plastic molded part. The invention further relates to an injection molding device with which such a plastic molded part can be produced, and to such a plastic molded part.The production of one-component or multicomponent plastic molded parts having a hole at least in a plastic component of the plastic molded part presents a challenge, since the hole production can lead to quality problems on the plastic molded part.It is already known to use a complementary projection which projects into the cavity for hole production, around which projection the plastic compound flows during injection molding and then cools. It is disadvantageous that when this projection flows around it, an inner seam is formed at its rear region in the flow direction, where the fronts of the plastic compound converge. This impairs the product or has to be dissolved by renewed supply of heat.Another possibility known from the prior art consists in producing the hole subsequently in the manufactured component by a mechanical process. There is a risk of chipping at the hole edges.An object on which the invention is based can be seen in the fact that an injection molding process is specified, by means of which hole production is possible with high product quality in a simple and process-safe manner. In particular, the method is intended to make possible the production of one-component molded plastic parts optionally with an insert part or of multi-component molded plastic parts optionally with an insert part. Furthermore, the invention aims to provide an injection molding device for producing a one- or multi-component plastic molded part having a hole at least in a plastic component of the plastic molded part.The object underlying the invention is achieved by the features of the independent claims. Advantageous embodiments and developments are the subject matter of the dependent claims.Accordingly, an exemplary injection molding method for producing a one- or multicomponent plastic molded part having a hole at least in a plastic component of the plastic molded part comprises the steps: An injection molding method for producing a one- or multicomponent plastic molded part having a hole at least in a plastic component of the plastic molded part comprises the steps: approaching two mold plates of an injection molding device, wherein a cavity is formed between the mold plates, which cavity comprises a cavity region for hole production and a cavity region surrounding this cavity region for producing the plastic component of the one- or multicomponent plastic molded part. A plastic compound is injected into the cavity by means of a plastic feed which opens into the cavity region for hole generation. In the still plastic state of the plastic composition, at least one of the two mold plates is moved toward the other mold plate, wherein, as a result of the plate movement, the cavity region for hole generation and the cavity region for generation of the first plastic component are substantially separated from one another.Since the cavity region for hole generation and the cavity region for generating the plastic component are connected during the injection process, the plastic compound can be distributed uniformly and without problems in the cavity. For hole production, the movement of the two mold plates towards each other is then used. This process, which is also referred to in injection molding technology as an embossing process, essentially separates the cavity region for hole production and the cavity region for production of the plastic component. In other words, a perforated disk produced in the cavity region for hole production is substantially separated from the plastic component by the stamping process.The separation need not be complete, but it is possible and in practice also the rule that a thin web region remains between the plastic pane and the plastic component. "Substantially separated from one another" thus means that the parts are nearly or completely separated. This can mean, for example, that the parts are separated from one another to such an extent that they can be torn apart from one another without damage by a mechanical action (for example by a demolding process).After the plastic composition has cooled in the two cavity regions, the mold plates can be moved apart. Subsequently, the plastic disk (perforated disk) formed in the cavity region for hole generation can be removed. The removal of the plastic pane, i.e. the gate separation, can thus be carried out in the process. It can be effected, for example, by moving the mold plates apart.As already mentioned, when separating the cavity regions, a remaining gap can remain between the cavity regions, in which gap a web is formed between the plastic component and the plastic pane (the shape of which can be complementary to the hole in the first plastic component). The gap dimension (or the thickness of the web) can be equal to or less than 2 / 10 mm or 1 / 10 mm.The separation of the cavity regions can mean that when the plastic component is removed from the injection molding device or even earlier, namely when the mold plate is moved apart, the plastic connection (web) between the plastic disk and the plastic component breaks off. It is also possible for this plastic connection to tear off already during the shrinkage process in the injection molding device (tool). If further plastic components are injection-molded onto the plastic component, the removal of the plastic pane is carried out before these further process steps.Embodiments of the injection molding process can be used particularly advantageously for the production of multicomponent plastic molded parts. Multicomponent plastic molded parts comprise one of the (first) plastic components and another (second) plastic component. A further development of the described method can be characterized in that a further cavity for a further plastic component is formed between a further (third) mold plate and the molded part, and a further plastic compound is injected into the further cavity. In this way, the one-component molded part with a hole can be further processed to form a two- or multi-component molded plastic part.In this case, the further cavity can annularly surround the region of the hole in the plastic component. In this way, a hole is also formed in the further plastic component. In this case, the contour surfaces of the cavity region for the production of the plastic component and of the further cavity can be formed in such a way that the hole edge of the (first) plastic component is flush (e.g. free of creases) with the hole edge of the further (second) plastic component. However, it is also possible for the further plastic component to project radially in the interior of the hole beyond the first plastic component.For example, an insert, in particular a film, can be inserted in the cavity region for the production of the plastic component. It can be provided here that the further plastic component encapsulates the edge of the insert part towards the hole.When an insert part is injection-molded from behind, a particular advantage of the injection molding method disclosed here is that no disturbances (e.g. wrinkling) occur on the insert part during the injection process. In the conventional method, there is the risk of wrinkling of the insert (e.g. foil) if the hole-forming protrusion in the cavity is in contact with the insert during the injection process, clamps the insert, and the inflowing plastic compound exerts tensile forces on the insert during filling of the cavity.An example of an injection molding apparatus for producing a one- or multi-component plastic molded part having a hole in at least one plastic component comprises a first mold plate and a second mold plate configured to form a first cavity between the first and second mold plates. The first cavity has a cavity region for hole production and a cavity region surrounding this cavity region for producing the first plastic component of the single-component or multicomponent plastic molded part. The injection molding device further comprises a plastic feed, which opens into the cavity region for hole production. The contour surfaces of the cavity regions are shaped such that, when the mold plates are closed, the cavity region for hole generation and the cavity region for generation of the first plastic component are substantially separated from one another.The plastic feed in the first mold plate can be designed such that it opens into a trough-shaped depression of the first mold plate, which depression has a contour surface of the cavity region for hole production. In this case, the first mold plate forms the trough plate for the production of the plastic pane.The second mold plate may have a mold protrusion having a contour surface of the cavity region for hole generation. Adjacent to the mold projection, a contour surface of the cavity region for producing the first plastic component in the second mold plate may be provided. In this case, the second mold plate can form the trough plate for the production of the first plastic component.The first mold plate can have a circumferential step on a contour surface of the cavity region for producing the first plastic component. The circumferential step can serve, for example, as a centering step for an insert part (e.g. film). It can protect the insert part from under-flushing during the injection process and can also have the effect that, during the filling of the first cavity, the insert part is pressed by the inflowing plastic compound onto the contour surface of the cavity region for the production of the first plastic component in the first mold plate. This enables reliable filling of the first cavity and can prevent the insert from wrinkling or otherwise being adversely affected by the injection process. This also contributes to the fact that the plastic feed leads into the cavity region for hole production, so that the incoming plastic compound acts upon the insert part with radial forces acting in all lateral directions (which thus cancel one another out).The second mold plate can have an ejector that can be advanced into the cavity region for hole generation. The ejector can be realized, for example, as an ejector plate which forms a large part of the contour-forming surface or the entire contour-forming surface of the second mold plate for the perforated disk. The ejector makes it possible to remove the plastic pane from the first plastic component while it is still fixed to the second mold plate, for example.The first mold plate may include a pusher that is advanced into the cavity region for the generation of the first plastic component. The pusher makes it possible to retain the first plastic component on the second mold plate while at the same time, for example by means of the ejector, the plastic disk is separated and / or removed from the first plastic component.The cavity region for hole generation can be bounded on the first mold plate by a contour surface which has a circumferential marginal edge. The cavity region for producing the first plastic component can be bounded on the second mold plate by a contour surface which likewise has a circumferential marginal edge. The two marginal edges can be aligned with one another. The distance between the marginal edges in the vertical direction (closing direction) can define the opening width of the gap between the closed molded plates or the thickness of a optionally still present plastic web between the plastic pane and the first plastic component.The invention further relates to a one-component or multicomponent plastic molded part having a hole at least in a plastic component of the plastic molded part. The hole is substantially produced by injection molding. In the vicinity of the hole, a plastic structure with melt fronts revolving around the hole is present in the plastic component.The melt front occurring during the filling process spreads in the radial direction (since at the time of the injection process the connection between the two cavity regions is still present). Thus, the plastic structure does not have any internal seams in the vicinity of the hole, which are formed by melt fronts that meet one another. In this respect, high-quality plastic molded parts with a hole can be produced, in particular optical plastic molded parts or glazing plastic molded parts. The plastic molded part can be formed as a one-component or multicomponent plastic molded part with or without an insert part, wherein the hole is present in at least one plastic component (and in particular, for example, in all plastic components).Exemplary embodiments are explained below with reference to the drawings. Identical or corresponding parts are provided with the same reference numerals. Features of the illustrated exemplary embodiments can be combined with one another selectively, provided that they are not alternative or technically exclusive features. Further, features of the embodiments may be selectively omitted unless described as mandatory features in the description. FIG. 1 shows examples of one-component or multicomponent plastic molded parts in schematic sectional representations (A) to (D). FIG. 2 shows examples of a two-component plastic molded part with an insert part in a schematic partial sectional illustration (section line A-A) and in a plan view in the region of a hole. FIG. 3 shows a sectional view of a section of a first and a second mold plate with an intermediate first cavity before the injection of the first plastic compound for the first plastic component into the region in which a hole is to be produced in the plastic molded part. FIG. 4 shows the arrangement of FIG. 3 during or after the injection of the first plastic compound into the cavity. FIG. 5 shows the arrangement of FIG. 4 after the mold plates have been moved toward one another (stamping process). FIG. 6 shows the arrangement of FIG. 5 during the severing of the plastic pane during the opening of the mold plates. FIG. 7 shows the arrangement of FIG. 6 after the separation of a plastic pane (perforated pane) from the plastic component (gate separation) during the ejection thereof. FIG. 8 shows a section of a third mold plate of the injection molding device in a sectional view, by means of which a second cavity is created between the molded part formed in the first cavity and the third mold plate. FIG. 9 shows the arrangement of FIG. 8 after the injection of the second plastic compound into the second cavity. FIG. 10 shows curves of the melt fronts (flow front) during the filling of the first cavity. FIG. 11 shows a first example of a three-component plastic molded part with an insert part in a schematic partial sectional illustration and in a plan view in the region of a hole. FIG. 12 shows a sectional view of a section of a first and a second mold plate with an intermediate first cavity before the injection of the plastic compound into the region in which a hole is to be produced in the plastic molded part. FIG. 13 shows the arrangement of FIG. 12 during or after the injection of the first plastic compound for the first plastic component into the first cavity. FIG. 14 shows the arrangement of FIG. 13 after the mold plates have been moved toward one another (stamping process). FIG. 15 shows a sectional view of a section of a fourth and a fifth mold plate with an intermediate second cavity before the injection of a second plastic compound for the second plastic component into the region of the second cavity in which a hole is to be produced in the plastic molded part. FIG. 16 shows the arrangement of FIG. 15 during or after the injection of the second plastic compound into the second cavity. FIG. 17 shows the arrangement of FIG. 16 after a movement of the fourth and fifth mold plates toward one another (stamping process). FIG. 18 is a cross-sectional view of a portion of the fifth and sixth third cavity mold plates prior to injecting a third plastic compound for a third plastic component into a third cavity. FIG. 19 shows the arrangement of FIG. 18 after the injection of the third plastic compound into the third cavity. FIG. 20 shows a second example of a three-component plastic molded part with an insert part in a schematic partial sectional illustration and in a plan view in the region of a hole. FIG. 21 shows a sectional view corresponding to FIG. 16 of a section of a fourth and a fifth mold plate with an intermediate second cavity after injection of a second plastic compound for the second plastic component into the region of the second cavity in which a hole is to be produced in the plastic molded part. FIG. 22 shows the arrangement of FIG. 21 after moving the fourth and fifth mold plates toward each other (stamping process). FIG. 23 is a cross-sectional view of a portion of the fifth and sixth mold plates with third cavity therebetween prior to injecting a third plastic compound for the third plastic component into a third cavity.FIG. 1 shows an example of a one-component plastic molded part 100 in (A) in schematic sectional illustration. The plastic component is referred to below as first plastic component 1K.The plastic molded part 100 has a hole 120. The hole 120 may be a through hole through which the first resin component 1K passes.In (B), another example of a one-component molded plastic part 100 is shown. This plastic molded part 100 differs from the plastic molded part 100 in (A) in that it has an insert part ET. The insert ET can be, for example, a foil or another, for example planar, insert.Inserts ET differ from plastic components in that they are prefabricated. That is, an insert part ET is not formed in the injection molding method described herein, but is inserted into a cavity used in the injection molding method described herein and then overmolded with a plastic component.In the plastic molded part 100 shown in (B), the insert part ET is back-molded by the first plastic component 1K. The hole 120 extends through the first plastic component 1K and may also extend through the insert ET. However, it is also possible that the hole 120 does not penetrate the insert part ET.FIG. 1 shows an example of a multicomponent plastic molded part 100 at (C). This plastic molded part 100 comprises at least a first plastic component 1K and a second plastic component 2K. The hole 120 may extend through one or both plastic components 1K, 2K. Both the first plastic component 1K and the second plastic component 2K are manufactured in the injection molding method described here, i.e. are not prefabricated parts.The plastics of the first plastics component 1K and of the second plastics component 2K can be different from one another.The first plastic component 1K can be, for example, a base body of the plastic molded part 100. The first plastic component 1K can be flat and / or thin-walled. The first plastic component 1K can consist, for example, of a transparent plastic material or an opaque plastic material.The second plastic component 2K can be injection-molded onto a main surface of the first plastic component 1K. For example, the second plastic component 2K can be a transparent plastic component. The second plastic component 2K can likewise be embodied in a planar and / or thin-walled manner. Its outwardly facing surface can be, for example, a visible surface of the multicomponent plastic molded part 100, i.e. a surface which is visible to a viewer in the installed state of the component and must therefore meet particularly high requirements for optical freedom from defects.In the example of a plastic molded part 100 shown in (D), an insert part ET is located between the first plastic component 1K and the second plastic component 2K. The hole 120 runs through the first plastic component 1K, optionally the insert part ET and optionally the second plastic component 2K. Alternatively, the hole 120 can pass through the second plastic component 2K, optionally the insert part ET and optionally the first plastic component 1K.The plastic components 1K, 2K and the insert part ET may have main surfaces which are each parallel to one another. The wall thickness of the insert part ET can be, for example, less than the wall thickness of the first plastic component 1K and / or of the second plastic component 2K. The plastic components 1K and 2K can each be manufactured, for example, from polycarbonate (PC). The lateral dimensions of the plastic components 1K, 2K can be the same or different and can each be, for example, equal to or greater than or less than 10 cm, 30 cm, 60 cm or 90 cm. The wall thicknesses of the plastic components 1K, 2K can be the same or different and can each be, for example, the same or greater or less than 1 mm, 5 mm, 10 mm, 20 mm, 30 mm or 40 mm.The insert part ET can be a decorative part which determines the optical system of the plastic molded part 100. It is also possible for the insert part ET to be an electrical functional element, for example, such as a heating film with integrated heating wires. The insert part may contain or be a film, for example PVC film. The thickness of the film can be, for example, less than the wall thickness of the plastic components and can be, for example, between 0.1 mm and 1 mm, in particular 0.3 mm and 0.6 mm.The opening width of the hole 120 may vary over a wide range. For example, the opening width (e.g. diameter or minimum dimension of the hole opening) can be greater than the wall thickness of the plastic molded part. In particular, opening widths can be, for example, equal to or greater than or less than 5 mm, 10 mm, 20 mm, 40 mm, 60 mm or 80 mm.The plastic molded part 100 can be provided, for example, for insertion into a body opening of a motor vehicle. For example, the plastic molded part 100 can be a motor vehicle front cover and / or a motor vehicle headlight cover (wherein the motor vehicle headlight cover can be integrated into the motor vehicle front cover, for example). The hole 120 can be, for example, an opening for a sensor, e.g. a distance radar.FIGS. 3 to 9 show exemplary process steps which can be carried out for producing a one- or two-component plastic molded part 200 according to FIG. 2. The hole edge of the plastic molded part 200 is identified in FIG. 2 by the reference symbol 210. The hole edge 210 has, for example, a rounded course in the thickness direction of the plastic molded part 200.The hole edge 210 can be shaped differently. For example, in the transition between the first plastic component 1K and the second plastic component 2K, a transition without contours and / or creases can be present. For example, the apex of the hole edge 210 may coincide with the transition between the first plastic component 1K and the second plastic component 2K.In other examples (see the dot-dash line profile of the second plastic component 2K in FIG. 2 ), the second plastic component 2K can project radially inward beyond the first plastic component 1K (e.g. according to the hole edge 210', see also the description relating to FIGS. 8 and 9 ).FIG. 3 shows a schematic illustration of a section of an injection molding device 300. The injection molding apparatus 300 includes a first mold plate 310 and a second mold plate 320. The first mold plate 310 and the second mold plate 320 may be disposed on opposite halves of a mold. The first mold plate 310 and the second mold plate 320 can be, for example, mold halves or inserts which are realized in mold halves.FIG. 3 shows the mold plates 310, 320 in the collapsed but not yet fully closed state. Between the mold plates 310, 320, a (pre-enlarged) first cavity 330 for injecting a plastic compound is formed.The first cavity 330 or the plastic compound is referred to below without limiting generality as a 1K cavity 330 or 1K plastic compound 1M, in order to distinguish it from a second cavity or a second plastic compound 2M in the case where a plastic molded part 100, 200 is produced with a second plastic component 2K.The first cavity 330 has a cavity region 330_ 1 for the hole generation and a cavity region 330_ 2 surrounding this cavity region 330_ 1 for the generation of the first plastic component 1K. In the position of the mold plates 310, 320 shown in FIG. 3, the two cavity regions 330_ 1, 330_ 2 are connected to one another.The first mold plate 310 has a plastic feed 312 which opens into the cavity region 330_ 1 for hole generation. The cavity region 330_ 1 may be bounded, for example, by a trough-shaped depression 314 of the first mold plate 310, wherein the trough-shaped depression 314 may have a contour surface 314C of the cavity region 330_ 1 for hole generation.The second mold plate 320 may include, for example, a mold protrusion 324 having a contour surface 324C of the cavity portion 330_ 1 for hole generation.The cavity region 330_ 2 for producing the first plastic component 1K has contour surfaces 316C, 326C, e.g. on the first mold plate 310 or the second mold plate 320.The contour surface 314C of the cavity region 330_ 1 for the hole generation on the first mold plate 310 may have a circumferential marginal edge 318. The contour surface 324C of the cavity region 330_ 1 for the hole generation on the second mold plate 320 may have a circumferential marginal edge 328. The marginal edges 318, 328 may be aligned with one another in the closing direction (corresponding to the vertical direction in FIG. 3 ).The contour surfaces 314C, 324C, 316C, 326C of the cavity regions 330_ 1 and 330_ 2 may be shaped such that, when the mold plates are closed (see FIG. 5 ), the cavity region 330_ 1 for hole generation and the cavity region 330_ 2 for generation of the first plastic component 1K are substantially separated from one another. The separation may be effected by opposing marginal edges 318, 328.The first mold plate 310 may have a pusher 319 that can be advanced into the cavity region 330_ 2 for producing the first plastic component 1K. The pusher 319 may surround the cavity portion 330_ 1 for hole generation. It can have, for example, one or more pusher elements which are arranged around the cavity region 330_ 1 and overlap with the cavity region 330_ 2.The second mold plate 320 may have an ejector 329 that can be advanced into the cavity region 330_ 1 for hole generation. The ejector 329 can be arranged, for example, opposite the plastic feed 312. In FIG. 3, the ejector 329 is in the retracted state.The first mold plate 310 may have a circumferential step 317 on the contour surface 316C of the cavity region 330_ 1 for producing the first plastic component 1K. The circumferential step 317 can serve as a centering step for an insert part ET. The step 317 can be shaped complementarily to an opening in the insert part ET. The step 317 can protect the insert part ET against slipping and folding, in particular during the injection process, during which the inflowing 1K plastic compound 1M pulls on the insert part ET. Step 317 also causes the inflowing plastic compound 1M to press the insert part ET against the region of the contour surface 316C of the first mold plate 330_ 1 running under the insert part ET and cannot pass between this region of the contour surface 316C and the insert part ET.FIG. 4 shows the injection process into the pre-enlarged cavity 330. The 1K plastic compound 1M is injected into the first cavity region 330_ 1 and spreads into the second cavity region 330_ 2. In this case, the 1K plastic compound 1M flows through a gap between the mold plates 310, 320, which is bounded, for example, by the marginal edges 318, 328. The 1K cavity 330 is closed in the outer edge region (not shown) (for example by embossing strips), so that the 1K cavity 330 can be filled under high pressure.FIG. 5 shows that when the mold plates 310, 320 are moved or when the gap is closed, the cavity regions 330_ 1, 330_ 2 are substantially separated from one another. The 1K plastic compound 1M is still plastic in this process phase, i.e. is present as a melt. When the gap is closed (almost completely or completely), the marginal edges 318, 328 can be brought into opposition to and, for example, into contact with one another. A defined tear line without burr formation can be generated between the plastic in the cavity region 330_ 1 for hole generation and the plastic in the cavity region 330_ 2 for generation of the first plastic component 1K. At this tear-off line, for example, a complete (burr-free) separation of the perforated disk produced in the cavity region 330_ 1 from the first plastic component 1K produced in the cavity region 330_ 2 takes place still in the tool (i.e. between the mold plates 310, 320) or, for example, during demolding.Since the melt is plastic at the time of the hole forming, the hole (except for the final separating process if appropriate) is produced by injection molding (more precisely by an injection stamping process).When the mold plates 310, 320 are closed, a gap between the mold plates 310, 320, which gap optionally still connects the cavity regions 330_ 1, 330_ 2, can have a gap dimension equal to or smaller than 2 / 10 mm, 1 / 10 mm or 5 / 100 mm.As described above, the first resin component 1K is manufactured by a so-called embossing method (injection-embossing). In an embossing method, the liquid 1K plastic compound 1M is injected into the pre-enlarged 1K cavity 330 between the mold plates 310, 320, or which increases during the injection process, and is subsequently pressed in the thickness direction while carrying out a mold plate movement. Injecting the 1K plastic compound 1M into the enlarged 1K cavity 330 facilitates filling of the cavity. In addition, the mold plate movement during the cooling phase compensates for shrinkage and thus enables the production of particularly low-stress plastic molded parts. Embossing methods are used in particular for the production of high-quality, thin-walled and large-surface shaped parts.Depending on the desired shape of the hole 120, a contour line between the cavity regions 330_ 1 and 330_ 2, which can be defined, for example, by the mutually contacting marginal edges 318, 328, can generally have any desired circumferential shape (e.g. circular, oval, polygonal, star-shaped, etc.).After the 1K plastic composition 1M has cooled in the 1K cavity 330, the mold plates 310, 320 are opened (FIG. 6 ). When the mold plates 310, 320 are opened (or else at an earlier or later point in time), the 1K perforated disk 610 formed in the cavity region 330_ 1 is removed from the first plastic component 1K. For this purpose, the first plastic component 1K can be held fast on the second mold plate 320 during the opening movement of the mold plates 310, 320, for example by the pusher or the plungers 319 (or by another mechanism). At the same time, the 1K orifice plate 610 may be retained to the first mold plate 310. For example, this can be done by the ejector 329 pressing against the 1K perforated disk 610 from above. When the mold plates 310, 320 are opened, it is possible, for example, to achieve burr-free tearing of the 1K perforated disk 610 from the first plastic component 1K. FIG. 7 shows the ejection of the perforated disk 610 from the injection molding device (tool) 300 by means of the ejector 329. This is pushed forward for this purpose.In other words, when the injection molding apparatus 300 is opened, the pusher 319 can hold the first plastic component 1K in the cavity in the second mold plate 320, wherein at the same time the perforated disk 610 is possibly separated and ejected by the ejector 329.The ejector 329 can also be realized, in a manner not shown, for example as an ejector plate which forms a large part of the contour-forming surface or even the entire contour-forming surface of the second mold plate 320 for the perforated disk 610 (plastic disk).With the method or the injection molding device of FIGS. 3 to 7, one-component plastic molded parts 100 of representations (A) and (B) of FIG. 1 can be produced. In this case, the first plastic component 1K with optional insert part ET forms the finished (single-component) plastic molded part 100. Examples are described below in which the first plastic component 1K is further processed in order to produce two-component plastic molded parts 100 of representations (C) and (D) of FIG. 1 or higher-component (e.g. three-component) plastic molded parts. In this case, after removal of the 1K perforated disk 610, the second plastic component 2K is attached to the prefabricated first plastic component 1K (or a molded part which contains the first plastic component 1K). Referring to FIG. 8, the first resin component 1K may be left in the second mold plate 320 and a third mold plate 810 may be placed opposite to the second mold plate 320. In this case, a 2K cavity 830 is formed between the third mold plate 810 and the first plastic component 1K.A contour surface 814C delimiting the 2K cavity 830 can adjoin the edge course of the first plastic component 1K flush and, for example, without any creases (i.e., for example, to the contour surface 326C of the second mold plate 320). In this case, a smooth hole edge 210 without step is formed. Furthermore, the contour surface 814C can be designed such that the insert part ET is completely encapsulated in the hole edge region. By completely enclosing the insert part ET in the hole edge region, it can be prevented that this is impaired, for example, by dirty water or other external influences.Alternatively, it is possible for the contour surface 814C delimiting the 2K cavity 830 to project inwardly beyond the edge of the first plastic component 1K (see the dot-dash line 814C'). A section of the contour surface 324C of the second mold plate 320 then also forms a contour surface for the second plastic component 2K. Edge mouldings 210' can be produced as shown in Figure 2.FIG. 9 shows the injection molding device 300 after the injection of a 2K plastic compound 2M into the 2K cavity 830. The supply of the 2K plastic compound 2M can be effected in any desired manner, for example laterally by means of a so-called film gate. For injection molding the second plastic component 2K onto the first plastic component 1K, an injection molding method without plate movement can be used. However, it is also possible to produce the second plastic component 2K by means of an injection-stamping method.After opening the mold plates 320, 810, the plastic molded part 200 can be removed from the tool (demolded).FIG. 10 shows curves of the melt fronts S (flow fronts) during the filling of the 1K cavity 330 with the 1K plastic compound 1M. The melt fronts S expand in the radial direction in the cavity region 330_ 1 and the cavity region 330_ 2. The melt fronts S may have arcuate contours, which are illustrated in FIG. 10 by concentric circular lines.In particular, the course of the melt fronts S in the vicinity of the hole 120 does not have any creases. Thus, neither inhomogeneities (e.g. joint lines) nor optical defects arise in and / or on the first plastic component 1K.The profiles of the melt fronts S are optically detectable in the plastic structure on the finished plastic molded part 100, 200. They can be made visible, for example, by slice image methods or other examinations and / or they can be optically recognized with the eye by direct illumination. That is to say that the central injection molding of the first plastic component 1K onto the perforated disk 610 is directly detectable in the finished plastic molded part 100 on the basis of the course of the melt fronts S.FIGS. 11 to 19 and FIGS. 20 to 23 show two examples for producing three-component plastic molded parts 1100 (FIG. 11 ) and 2000 (FIG. 20 ), respectively. The plastic molded part 1100 has the first plastic component 1K, the second plastic component 2K, an (optional) insert part ET and a third plastic component 3K. In the example shown here, the hole 120 runs through all the plastic components 1K, 2K, 3K. However, it can be provided, for example, that the hole 120 passes through only the first and second plastic components 1K, 2K, while the third plastic component 3K is continuous.FIG. 12 shows a first mold plate 310 and a second mold plate 320 in a position in which the 1K cavity 330 is pre-enlarged. To avoid repetitions, reference is made to the description relating to FIG. 3. The first mold plate 310 can differ from the first mold plate 310 of FIG. 3, for example, in that it does not form a circumferential step 317. That is, the contour surface 314C delimiting the trough-shaped depression 314 can transition at the edge 318 into a planar contour surface 316C of the cavity region 330_ 2.The second mold plate 320 may differ from the second mold plate 320 shown in FIG. 3 in that the mold protrusion 324 merges into the contour surface 326C not via a peripheral fillet, as in FIG. 3, but via a step (e.g. vertical step). The insert ET may be secured to the second mold plate 320 in this and other examples. Instead of the circumferential step 317 in FIG. 3, the stepped configuration of the shaped projection 324 can serve for this purpose.Similar to FIG. 3, the first mold plate 310 may be equipped with a pusher 319 (not shown).FIGS. 13 and 14 show the processes already explained with reference to FIGS. 4 and 5, wherein reference is made to the above description.After injection-molding the first plastic component 1K and removing the perforated disk 610 (see FIG. 7 ), the second plastic component 2K can optionally be injection-molded. In FIG. 15, this is done by means of a fourth mold plate 1510 and a fifth mold plate 1520. The fourth shaped plate 1510 has a plastic feed 1512 for the second plastic component 2K. The fifth mold plate 1520 may be embodied similarly or identically to the second mold plate 320, i.e. the first plastic component 1K may also remain in the second mold plate 320. An ejector of the fifth mold plate 1520 is designated by reference numeral 1529. It can be identical in construction to the ejector 329 of the second mold plate 320, for example (see also the above description of the ejector plate). The contour surfaces 326C serve here for injection molding the second plastic component 2K.FIG. 16 shows the filling of the 2K cavity 830 with the 2K plastic compound 2M. For this purpose, the 2K cavity 830 comprises a first cavity region 830_ 1 and a second cavity region 830_ 2 which are connected to one another at the time of filling. A step of the fourth mold plate, against which the prefabricated molded part (e.g. plastic component 1K and insert part ET) abuts, protects the insert part ET from the inflowing 2K plastic compound 2M.The sequence and the mode of operation of the production of the second plastic component 2K in this example substantially correspond to the production of the first plastic component 1K, for which reason reference is made to the above explanations. As already described, an injection-compression molding method is used, in which the pre-enlarged 2K cavity 830 is divided into the two separate cavity regions 830_ 1 830_ 2 by means of a plate movement. The 2K perforated disk 1710 (sprue) is produced in the cavity region 830_ 1, while the second plastic component 2K IS FORMED IN THE CAVITY REGION 830_ 2 (FIG. 17 ).The separation of the 2K perforated disk 1710 from the second plastic component 2K can be effected in a similar or similar manner to the separation of the 1K perforated disk 610 from the first plastic component 1K. For this purpose, the ejector 1529 in the fifth mold plate 1520 may be used. Reference is made to the above description. In particular, a burr-free separation is possible.A third plastic component 3K can optionally be injection-molded in the following. To this end, the fifth mold plate 1520 may be placed in opposition to a sixth mold plate 1810. The molded part may be located in the fifth mold plate 1520. The sixth mold plate 1810 may form a 3K cavity 1830 for the third plastic component 3K between the sixth mold plate 1810 and the molding. By injecting a 3K plastic compound M 3 (not shown), the three-component plastic molded part is finished (see FIG. 19 ).In the example shown here, for example, the first plastic component 1K and the second plastic component 2K are produced by an injection-stamping method, while the third plastic component 3K is formed by an injection-moulding method (without plate movement). For example, it is possible for the third plastic component 3K to close the hole 120 in the manner of a window. In the example shown here, the third plastic component 3K is shaped such that the hole 120 also runs through the third plastic component 3K. In this case, the edge region of the hole 120 can transition flush from the second plastic component 2K into the third plastic component 3K. The third plastic component 3K can encapsulate the first plastic component 1K and optionally the insert part ET, i.e. completely cover it at the hole edge.FIGS. 20 to 23 show exemplary process steps of a method for producing a plastic molded part 2000. The plastic molded part 2000 can likewise be a three-component plastic molded part, but the individual process steps can also be used for producing corresponding one- or two-component plastic molded parts.In the case of the plastic molded part 2000, the encapsulation is carried out at the edge region of the hole by the second plastic component 2K. Otherwise, identical or similar process sequences as in the case of the plastic molded part 1100 can be used.FIG. 21 shows the production of the second plastic component 2K corresponding to FIG. 16 The first plastic component 1K can be produced, for example, as illustrated in FIGS. 12 to 14. The first plastic component 1K is then removed from the second mold plate 320 and fixed on a fifth mold plate 1520 with 2K plastic feed 1512. By means of an injection-compression process (see the description relating to FIGS. 16 and 17 ), the second plastic component 2K is injection-molded and the gate separation for hole production in the second plastic component 2K is subsequently carried out (see FIG. 22 ). For this purpose, the ejector 1529 can be inserted in a fifth mold plate 1520 with contour surfaces 326C for the second plastic component 2K.FIG. 23 shows the injection molding of the third plastic component 3K between the fifth mold plate 1520 and a sixth mold plate 1810, compare FIG. 19.In the case of both plastic molded parts 1100 and 2000, the first and second plastic components 1K and 2K are produced, for example, by injection-stamping processes, while the third plastic component 3K is produced by an injection molding process without a central gate in the hole 120.All described device and method examples can be combined with one another, provided they are not technically exclusive. In particular, the disclosure of this document also encompasses combinations of individual features described on the basis of the examples with the claimed subject matters.All the plastic molded parts produced have in common that the hole is produced in the (still) plastic melt at least in one plastic component by an embossing process. The plastic molded parts have, for example, the following features:(1) The hole 120 is substantially injection molded (i.e., at least for the most part, e.g., except for the break which constitutes an additional mechanical process) because the melt is still plastic during hole making. That is, the hole edge surface takes the shape of the surface of a cavity contour surface. In conventional mechanically manufactured holes, the hole edge surface is produced by machining (e.g. machining, etc.) and can be clearly distinguished from an injection-molded surface.(2) In the case of a multicomponent plastic molded part with an insert, the insert can be completely encapsulated at the hole edge, for example by the second plastic component or a further (third) plastic component. The plastic component encapsulating the insert part can also be produced either in an injection-compression process with gate separation (e.g. FIGS. 20 to 23 ) or by an injection process without plate movement (e.g. FIGS. 2 to 10 or 12 to 19 ).(3) When producing a plastic molded part with film (as an insert), the film can be inserted into the cavity without having to be preformed beforehand (i.e. brought into the shape predefined by the cavity contour in a preceding process). This is made possible by the central sprue in the hole, by means of which the film is pressed against the contour surface of the cavity in the injection-stamping process.(4) The plastic structure of at least one plastic component has the hole in the region around the hole 120, for example melt fronts running around in an arc shape.In particular, the invention can relate to transparent plastic molded parts or so-called glazing plastic molded parts (with a mirror finish or "piano lacquer" surface optics) with a hole and with or without an insert. As already mentioned, in conventional molded parts of this type, structural inhomogeneities of the component around the hole 120 are directly visible, and in addition folds occur at the insert part ET (if present).

Claims

Injection moulding method for producing a one-component or multicomponent plastic moulded part having a hole at least in a plastic component of the plastic moulded part, wherein the method comprises the steps of: approaching two mould plates of an injection moulding device, wherein a cavity is formed between the mould plates, which cavity comprises a cavity region for hole production and a cavity region surrounding this cavity region for production of the plastic component of the one-component or multicomponent plastic moulded part; injecting a plastic compound into the cavity by means of a plastic feed which opens into the cavity region for hole production; and in the still plastic state of the plastic composition, moving at least one of the two mold plates toward the other mold plate, wherein, as a result of the plate movement, the cavity region for the hole generation and the cavity region for the generation of the first plastic component are substantially separated from one another.The method of claim 1, further comprising: moving the two mold plates apart after cooling the plastic compound in the two cavity areas; and removing a plastic disk formed in the cavity area for hole formation.Method according to claim 1 or 2, wherein, during the separation of the cavity regions, a remaining gap between the cavity regions has a gap dimension equal to or smaller than 2 / 10 mm or 1 / 10 mm.Method according to one of the preceding claims, wherein an insert, in particular a film, is located in the cavity region for producing the plastic component.The method of claim 2, wherein the plastic molding comprises a first plastic component and a second plastic component, wherein the first plastic component is formed by injecting the plastic compound into the cavity, and wherein the second plastic component is attached to a molding comprising the first plastic component after the plastic disk is removed.Method according to one of the preceding claims, wherein the plastic molded part comprises a first plastic component and a second plastic component, wherein the first plastic component is formed by the injection of the plastic compound into the cavity, and wherein the method for further processing the molded part having the first plastic component further comprises: forming a further cavity for the second plastic component between a further mold plate and the molded part; and injecting a further plastic compound into the further cavity.Method according to claim 6, wherein the further cavity annularly surrounds the region of the hole in the first plastic component, such that a hole is also formed in the second plastic component.Method according to Claim 6 or 7, wherein an insert, in particular a film, is located in the cavity region for producing the first plastic component, and wherein the second plastic component encapsulates the edge of the insert towards the hole.Injection moulding device for producing a one- or multicomponent plastic moulded part having a hole at least in a plastic component, which has: a first mould plate and a second mould plate which are designed to form a first cavity between the first and the second mould plate, which cavity region comprises a cavity region for hole production and a cavity region, surrounding this cavity region, for producing the first plastic component of the one- or multicomponent plastic moulded part; and a plastic feed which opens into the cavity region for hole production; wherein contour surfaces of the cavity regions are shaped such that, when the mould plates are closed, the cavity region for hole production and the cavity region for production of the first plastic component are substantially separated from one another.Injection moulding device according to claim 9, wherein the plastic feed is implemented in the first mould plate and opens into a trough-shaped depression of the first mould plate, which depression has a contour surface of the cavity region for hole production.The injection molding apparatus according to claim 9 or 10, wherein the second mold plate has a molding protrusion having a contour surface of the cavity portion for hole generation.Injection moulding device according to one of Claims 9 to 11, wherein the first mould plate has a circumferential step on a contour surface of the cavity region for producing the first plastics component.Injection moulding device according to one of Claims 9 to 12, wherein, with closed mould plates, a remaining gap between the cavity regions has a gap dimension equal to or smaller than 2 / 10 mm or 1 / 10 mm.Injection moulding device according to one of Claims 9 to 13, wherein the second mould plate has an ejector which can be pushed into the cavity region for hole production.The injection molding apparatus according to any one of claims 9 to 14, wherein the first mold plate includes a pusher that is advanceable into the cavity region for the generation of the first plastic component.Injection moulding device according to one of Claims 9 to 15, wherein the contour surface of the cavity region for the hole production on the first mould plate has a peripheral edge; the contour surface of the cavity region for the production of the first plastics component on the second mould plate has a peripheral edge; and the peripheral edges are aligned with one another.A one- or multicomponent plastic molded part having a hole at least in a plastic component of the plastic molded part, wherein the hole is produced substantially by injection molding and a plastic structure having melt fronts surrounding the hole is present in the plastic component in the vicinity of the hole.Single- or multicomponent plastic molded part according to Claim 17, wherein the melt fronts in the vicinity of the hole run in an arc-shaped or circular manner.Single- or multicomponent plastic molded part according to either claim 17 or claim 18, wherein the plastic molded part contains an insert part, in particular a film.The one- or multicomponent plastic molded part according to any one of claims 17 to 19, wherein the plastic molded part is a transparent molded part or a glazing molded part.Multicomponent plastic molded part according to one of Claims 17 to 20, which contains the plastic component and a further plastic component, the hole edge comprising the plastic component and the further plastic component or being formed by these.The multicomponent plastic molded part according to claim 21, wherein the further plastic component protrudes beyond the first plastic component into the hole.Multi-component plastic molded part according to one of claims 17 to 21, which contains the plastic component, a second plastic component and a third plastic component, wherein the hole edge comprises the second plastic component and the third plastic component or is formed by these.

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