DE102004043253B4 - Process for the production of plastic injection-molded parts and apparatus for carrying out the process - Google Patents

Abstract

method for the production of plastic injection molded parts, which decorative three-dimensional surfaces and several graphic elements in the background of a per se transparent Have parts in 3-D format, by controlled thermoforming, wherein at least one preform made of plastic, on which several graphic elements in two-dimensional Mold are imprinted, is inserted into the injection mold, a plastic with a temperature close to or equal to the melting temperature in the Mold cavity is pressed and the preform during molding of the graphic elements only in the area of engagement of individual stamps (5a), which form at least one stamp package (5), locally deformed becomes.

Description

The The invention relates to a method for the production of plastic injection molded parts and a device for implementation the method in which these plastic injection molded parts decorative three-dimensional surfaces and several graphic elements in the background of a per se transparent part in 3-D format, wherein at least one preform made of plastic, on which several graphic elements are printed in two-dimensional form are in the injection mold is inserted and a plastic with a temperature near or is pressed equal to the melting temperature in the mold space.

In constantly growing Scope come, especially in vehicle construction, home appliance technology and communication technology, plastic parts with lettering or graphic elements as operating elements with integrated function information for use. Such components are with high surface requirements and integrated information or graphical features preferred. Such plastic parts are by color variety, 3-D effect and freely selectable surface formation characterized and usually in injection molding and subsequently mechanical processing and coating technology in several processing stages produced.

In In any case, at least two or more are separate Complete process stages.

One known method is, for example, the back injection or overspray of preformed and color-coated foils.

The Going through several process stages inevitably leads to dangers the damage the surface the plastic part and / or influencing the coloring by mechanical Burdens and environmental influences. This limits the accuracy and visual requirements set and as well generates high process costs. Color variety and high optical as well accuracy requirements bump in the known method to technical limits, only with high Expenses and barely comprehensible can be broken.

When example for Known method is intended here to produce a badge for the design a visible from above contour of a gearshift knob a car are described.

The Plaque preferably has a surface in 3-D geometry, which is characterized by free-form surfaces and transparency characterized and has in the background information graphics, which should be visible again in 3-D format. While the Preparation of the badge, e.g. as plastic injection molded part, rather uncomplicated is the color design of the information graphic, especially in multicolor and 3-D format, as a complicated process represents.

First of all must One of the layers is a color coating by printing, varnishing or Get vaporized, with other levels are inevitably coated with and before the next Coating process in another color again locally stripped Need to become.

The Realization of the 3-D form requires the application of at least two coating / printing methods, since the coating on different levels within u.U. applied to very limited areas must become. Furthermore exists in the known technical solutions for the realization of respective process stages the requirement of application of different technical Facilities and tools. Multiple process stages also lead too high personnel expenses, several different qualification characteristics the performer and u.U. diverse Environmental protection activities.

From the DE 693 10 921 T2 a method for the production of plastic injection molded parts is known in which by controlled thermoforming with the introduction of at least one preform made of a plastic P1 in a mold cavity and optionally with the introduction of a second plastic P2 with a temperature close to or equal to the melting temperature of the plastic P2 into said mold space, after which said preform is heated to have different temperature ranges, at least one of the temperature ranges being close to or equal to the melting temperature of the plastic P1, and after shaping of the article in the mold by means of a mold cavity Stamp and / or the injection pressure of the plastic P2, when it is injected, takes place.

These technical solution has the disadvantage that only one predetermined by the stamp shape in unchangeable shaping possible is, i. it is not possible to use several graphic elements with different ones manifestations, especially different expression depths, in this way realize.

In particular, there is no possibility in the aforementioned method or this device, a temperature-dependent melting state of the plastic material by different temporal sequences of stamp operations for a diffe exploited expression of different graphical elements, because it is, since only one stamp available, even the introduction of a single graphic possible. In addition, if there is a slight change in a part of this graphic, the entire stamp must be rebuilt.

With the publication Patent Abstracts of Japan JP 07 009 482 A For example, a method and apparatus for injection molding decorative moldings having at least one hole will be described.

In a die and a corresponding counterform are combined with a Pair of punches or their countermarks by a decorative foil and the plastic part through a hole introduced in the manner that after clamping the decorative film is the injection of the melt resin. After a cooling and setting phase are applied to the decorative film or the plastic body stamp vibrated and softened and flowable by the generated heat. With the subsequent forward or backward pushing the stamp or Counter punch is the hole or the hole in the decorative film or the plastic part introduced.

Furthermore, an injection mold for decorative plastic parts with the publication Patent Abstracts of Japan JP 04 125 120 A played.

Of the The present invention is based on the object, a method and a device for to create the production of plastic injection molded parts, with the or the decorative three-dimensional surfaces and several graphical Elements in the background of a transparent part in 3-D format can be processed, that a temperature-dependent melt state of the plastic material and different time sequences of stamp operations for one differentiated expression different graphic elements is used, wherein a variability of the device for the Graphic training should be achieved.

According to the invention this Task solved by that by a controlled mold thermoforming, wherein at least a preform made of plastic, on which several graphic elements are printed in two-dimensional form, inserted into the injection mold is a plastic with a temperature close to or equal to the melting temperature is pressed into the mold cavity and the preform during molding the graphic elements only in the area of engagement of individual Stamps that form at least one stamp package, locally deformed is and so plastic injection molded parts, which decorative three-dimensional surfaces and several graphic Elements in the background of a transparent part in 3-D format have to be produced.

The Apparatus for carrying out of the method according to claim 1, comprising an injection mold, the a nozzle side for introducing the plastic melt and having an ejector side, arranged on the individual, at least one stamp package forming stamp are, wherein the at least one stamp package and / or individual stamp simultaneously and / or in different time series with different Drive systems, is formed displaceable in the mold space.

When one of the main advantages of this solution according to the invention the, by the time different introduction of the stamp packages or single stamp possible become, much greater variability of the device in terms of making changes to the plastic parts Call to be introduced graphic designs.

advantageous Further developments and refinements of the invention are evident from the remaining subclaims and from the principle described below with reference to the drawings embodiment seen.

It demonstrate

1 FIG. 2 is a sectional view of the device when it has been pulled apart; FIG.

2 : the device in partial sectional view,

3 : the device in sectional view in the phase of the beginning of penetration of the punches into the mold space,

4 : the device in section in the phase of penetration of the stamp in the molding,

The decorative plastic parts described above are produced according to the invention within an injection molding process without expensive intermediate stages. The injection molding process is carried out under the otherwise known conditions. For realizing the graphical elements in three-dimensional format, the known IMD method (in-mold decoration method) is used. At the beginning of the process, a film which is usually printed by screen printing is used 3 introduced and positioned in a suitable manner in the injection mold. In the following injection molding process, with the help of the process control of the injection molding machine, first the transparent (amorphous) molding compound on the film surface, ie recognizable side of the graphic up to determined filling volume of the molded part sprayed.

Until then, the slide 3 and thus the graphics are still in 2-D format.

During the filling process, the film heats up homogeneously 3 , which allows optimum deformability of the film.

With the cooling of the plastic to almost the glass transition temperature, a situation occurs that allows, by the mechanically operated contour punch 5a , from the ejector side 4 the machine forth against the mass present in the solidification process a forming process of the film 3 in the contour of the stamp 5a and depending on the thickness of the film 3 as well as travel of the stamp 5a to produce a more or less strong 3-D form.

By means of the control of the device it is possible to either have a complete stamp package 5 or single stamp 5a of the package 5 at a given time and / or temperature time to introduce into the mold space to allow a corresponding graphical surface design of the plastic part.

For example, in a part A with a graphic and surface to be produced, a first stamp 5a and a second stamp and a third stamp as a package 5 can be actuated individually or in different time sequence individually and in a part B with a graphic and surface to be produced just just the first punch and a part C of the first and third punch can be retracted into the mold space to form the special graphical structure.

So are in only one injection mold, for example three parts can be produced with different geometric graphics.

Of Furthermore, it is possible over the Timing of the retraction of the individual stamps for the graphics parts, at different temperature levels into the mold cavity retract. This makes it possible more or less pronounced To achieve contours in one and the same tool and at the same time to create a more or less depth or grandeur.

The Approaches of the individual stamps at different times and thus allow for different temperature levels it also in the surface structure different circumstances in terms of surface gloss or a desired one To create roughness.

1

Tool nozzle side

2

jet

3

foil

4

Tool ejector

5

stamp package

5a

stamp

6

cylinder

Claims (3)

Process for the production of plastic injection molded parts having decorative three-dimensional surfaces and a plurality of graphic elements in the background of a per se transparent part in 3-D format, by controlled thermoforming, wherein at least one preform made of plastic on which several graphic elements in two-dimensional form are imprinted, is inserted into the injection mold, a plastic with a temperature close to or equal to the melting temperature is pressed into the mold space and the preform during molding of the graphic elements only in the area of engagement of individual stamp ( 5a ) containing at least one stamp package ( 5 ) is deformed locally. Apparatus for carrying out the method according to claim 1, having an injection mold which has a nozzle side ( 1 ) for introducing the plastic melt and an ejector side ( 4 ), on the individual at least one stamp package ( 5 ) forming stamps ( 5a ), wherein the at least one stamp package ( 5 ) and / or individual stamps ( 5a ) at the same time and / or in different time sequence with different drive systems, is slidably formed in the mold space / are. Device according to claim 2, characterized in that that a plurality of stamp packages are provided, with which of the parting plane the injection mold Deviating levels of different levels can be produced.