DE102007061241A1 - Method for producing molded parts - Google Patents

Abstract

The invention relates to a method for producing molded parts with an openable and closable tool, wherein a flowable raw material in the tool receives a desired shape and is then cooled, wherein before introducing the flowable raw mass at least on a portion of a forming portion of the opened tool by means a decorative or typeface is applied to a printing process, wherein the applied decorative or typeface image is firmly and inseparably connected to the molding after cooling the flowable raw material.

Description

The The invention relates to a method for producing molded parts the preamble of claim 1.

From the EP 1 115 547 B1 a method for producing coated plastic moldings is known in which a composite plastic molding is produced. The composite plastic molding has at least one layer of a web material and a plastic body. Here, a web material is first placed between mold halves of an open injection mold. Subsequently, the web material is deformed by closing the tool. The deformed web material is held by means of negative pressure on one side or overpressure on the other side. Plasticized plastic is injected into a residual tool cavity and the tool is opened to a predetermined position. The web material may optionally have a decor, for example for furniture surfaces. This method has proven particularly useful in the production of a design that is essentially identical with respect to the surface decoration. With the disclosed method, however, it is only very cumbersome to produce components which, while not different in their shape, are intended to have a component-specific, individual décor.

From the DE 10 2004 050 290 A1 is a method and an apparatus for producing differently coated plastic moldings known. In this process, decorative films are prepared, which are manufactured component-individually before the injection molding process outside of the tool. Such a decorative film is inserted into the opened tool and back-injected by means of a plasticized plastic compound. Various decorative films are stored in different storage containers provided and are inserted by an industrial robot as needed in the injection mold.

This Method has also proven itself, but it is, the Number of storage tanks and the effort to prepare from decorative films on. In particular, the limited Number of different decors and / or encodings are avoided.

task The invention is therefore a method for producing molded parts specify with which it is possible without stocking to produce prefabricated decorative films of different types of molded parts, where an individual look and / or individual labeling can be applied. In particular, it should allow the process Moldings with the batch size 1 individually designed or coded. Furthermore, should a free choice of decor / Labeling of immediately before the production of the molding guaranteed be. Furthermore, moldings should be produced in any order be. Furthermore, a simplification of logistics costs, in particular due to less storage for customer-specific parts be achieved. In addition, reaction times to requests be accelerated by customers in terms of component design.

These Tasks are performed by a method having the features of the claim 1 solved. Advantageous embodiments are specified in the dependent claims.

The inventive method is characterized from that to be produced decorative or typeface image by means of a Printing process directly in the mold cavity on at least a portion of a forming portion of the mold cavity is applied. Under tool cavity here is particular a metal surface of the mold within the To understand molding cavity. As applying to a portion of the Tool cavity is also according to the invention the application of a printed image in the opened tool on a carrier foil, which is attached to the wall of the Werkzeugkavität is to understand. So it is with this formulation both a direct application to the surface of the mold cavity as well as an indirect application to a carrier medium, which is located in the mold cavity and at the Tool cavity is to understand.

essential to the invention is thus that the decor or typeface, which in the end be mounted on the molded part to be manufactured within the open Tool is generated. Here, the process is different much of the prior art, the decorative films outside of the tool are provided with decor and applied decor image be inserted into a tool and injected behind.

According to the invention was recognized that it certain media, such. B. printing varnishes, which are suitable for such an application in the tool, without the Marbling and smearing effects occur. Suitable for this purpose in particular pressure and temperature resistant paints, in particular Acrylic paints based on polymethyl methacrylates. Connect these paints in the tool during injection molding or pressing with plastic melt or plasticized plastic mass on cooling with this, so that the printed image after cooling the molding firmly and inseparably connected to the molding and this is so characterized, decorated or otherwise designed.

Prefers becomes a computer-controlled or computer-aided customizable Printing method used, which z. B. in the manner of an ink jet printing method, in the manner of a thermal transfer printing method or in the manner of a Pad printing process works.

Especially it is preferred that the decorative or typeface an individual or a single design or a pictogram or that the decor or typeface a serial number, batch number or otherwise the molded part is coding and characterizing code.

hereby For example, on mobile phone cases customized and person-specific photos of objects or persons are generated by means of printing process in the Werkzeugkavität the mobile phone shell were introduced. It is also, for example for documentation and security reasons very advantageous, Each manufactured plastic part an individual serial number assign, so that subsequent documentation forgery-proof and with little effort is possible.

The inventive method is suitable for all plastic molding processes and forming processes for Moldings.

Prefers is the method of the invention as plastic injection or Plastic injection molding process formed. in principle but this process is also for others to process Roughness imaginable, provided in terms of temperature and pressure load sufficiently resistant printing media / lacquers or the like are available or will be in the future. from inventive principle forth, this method is also under the above said condition also for the production of moldings from z. As metal or glass used.

According to one particular embodiment of the invention, the decorative or typeface on a carrier medium, which is in the Werkzeugkavität is applied. Such Carrier medium may for example be a release film or a Carrier foil for the decor or typeface, which open in the tool cavity Tool is located. An advantage of this measure is that regardless of the decor or typeface to be produced a standard or otherwise common orbit or Carrier material can be used, which in the Werkzeugkavität is inserted and at least in the area to be printed on the Werkzeugkavität is molded. On this carrier medium is then according to the invention applied the decorative or typeface.

at a first variant, the film remains after the spray or Spray-press process in the tool. The on the slide located Decor or typeface dissolves during the production process from this and connects to the plasticized plastic mass or the plastic melt. In this case, the tool works inserted foil as separating film or separation medium. In a second variant In this embodiment, the film remains after the manufacturing process of the molding on the molding and is cohesively with this connected. Thus, in this embodiment on the finished molding the decorative or typeface between the carrier film and the molded part body, so that the carrier film as scratch protection for the decor or typeface of the finished Shaped part can act.

For special optical or tactile surfaces may be appropriate be, as a carrier medium, a textile fabric, a carpet or leather or similar mats and / or sheet-like flat bodies to use.

Especially in 3-dimensional strongly contoured or relief-like areas, which are to be provided with the decorative or typeface, recommends It is, a printhead or other device by means of a print image is created in the tool cavity by means of an industrial robot with a constant distance to the tool cavity or to the surface on which the printed image is to be applied, to move.

A another possible embodiment of the invention Procedure provides that initially on a subarea a tool cavity applied a decorative or typeface which is before the injection of the flowable Raw material (plastic melt, plasticized plastic compound) by means of a cover sheet is covered. In this embodiment Thus, the carrier film is located on the finished molding between the decorative or typeface and the molding body. It is of particular advantage that the film with which the print image is covered in the tool, in terms of their adhesion properties for molding material and decorative or typeface material optimized and thus an improved Connection between the decorative picture and the molding body can be produced.

In particular, in a large-scale decor and / or typeface, it is advantageous if the printing medium, for. B. the printing varnishes are applied over a large area and in particular have chemical properties that facilitate the detachment of the finished molded part of the Werkzeugkavität. In such a case, the printing medium acts in addition to the formation of the decorative or typeface as a separation medium or release agent between the mold part of the mold cavity.

In particularly simple way can be electrically conductive Decors or patterns are applied to a component, if for the print medium is used electrically conductive paint. As a result, in particular with the method according to the invention in a simple way, a heatable mirror carrier or, for example, heated window and / or lenses of a Motor vehicle can be generated.

Provided the requirement is that the finished molding darkening properties It is recommended for the print medium one so-called LCD color to use, which by electrical control at least partially darkenable. Particularly suitable is this embodiment of the invention Process for the production of fully and semi-transparent molded parts and electrically controllable darkened moldings.

to Improvement of the mechanical connection between pressure medium and the molding, it has been proven, after the application of the Pressure medium, d. H. after making the decor or typeface mechanically roughen the print medium layer by means of a laser and / or to structure and / or to activate by means of energy input. hereby are increased by very small and fine bumps Binding forces between the print medium layer and the Molded body generated, so that the connection of these two Layers is improved.

A Activation of the surface can z. B. by laser or Plasma treatment or by flame treatment. Here are broken up by the introduced energy bonds, which then with the carrier again make new connections.

Especially the method according to the invention is suitable for Use in a so-called multi-component manufacturing process for plastic moldings. Here, for example, in a first step a transparent shaped body (first component) sprayed on which in a next step the decorative or typeface is applied, wherein the first component during this time remains in the tool. In a further step is after the application of the decorative or typeface image by injection or Pressing in flowable raw mass another Form part on, overmoulded or injected behind. This molding is then to consider as a second component. As a result, there is thus a molded part ago, which consists of two components, for example, two different ones Materials is formed, between which a decorative or typeface embedded is. This embodiment is particularly suitable for Component in which the first component has a transparent surface or a transparent surface layer. in this connection is especially the applied decorative or typeface on the finished Component visible.

Of course is the method of this multi-component design as well suitable for materials of the first and second components, that are not transparent. In this embodiment So a decorative or typeface between two non-transparent So opaque plastics embedded and is thus on the finished molding not visible. Such types of embedded, invisible images or fonts can be an authenticity feature, for example to combat claims of counterfeiting, especially for safety-related components, serve.

in the The invention will be more closely understood by way of example with reference to the drawing explained. It shows:

1 FIG. 2 schematically shows a flow diagram of a method according to the invention.

A method according to the invention for producing molded parts is designed, for example, as a plastic injection molding process and proceeds cyclically from the typical process, with a status of the process being selected for describing this example as the start of the cyclical process, in which an opened tool (step 100 ) is used in an empty, ready state in an injection molding machine. Such an injection molding tool consists of at least two mutually movable mold halves, which enclose a tool cavity between them. Under the Werkzeugkavität is a cavity to understand, in which by means of an injection process or by means of an extrusion process flowable raw material, eg. B. plastic melt or plasticized plastic is injected and injected by filling the mold cavity to a molding or pressed. Such an open tool has, for example, metallic mold surfaces and often has a three-dimensional contour in shaping areas.

According to the invention, a decorative and / or typeface image is now applied to the wall of the tool cavity on at least one subregion of shaping sections of the molding tool by means of a printing method (step 200. ). On the wear of the printed image, for example, by means of an inkjet, thermal transfer or pad printing process. In an ink-jet printing process, for example, a print head can be moved by a motor in the manner of a commercial inkjet printing unit along linear guides, and a print image can be moved by means of a suitable printing medium to the subarea in question Apply the mold cavity. If the part of the tool cavity to be imprinted has a 3-dimensional contour, e.g. B. relief-like structure, it is particularly advantageous to run an ink jet print head, for example by means of an industrial robot with a constant distance to the printing surface of the Werkzeugkavität so that a sharp print image is formed.

Acrylic coatings based on polymethylmethacrylate have proven to be suitable printing media in particular. Such coatings have a high resistance to compression deformation under high temperature action, as they typically prevail in a plastic injection molding tool. By means of such a printing process in the tool cavity "into" it is possible to completely save a stockpiling of suitably pre-printed insert films or Einlageträgermedien. After applying the decorative or typeface image, the tool is closed (step 300 ). Due to possibly existing suitable tempering, z. B. cooling or Aufheizeinrichtungen in the field of decorative printing manages the printed image to dry quickly or cure. In a next step, for example, when the tool is closed, a plasticized plastic material, eg. B. injected a plastic melt into the mold and thus the pressure, ie the decorative or typeface injected behind (step 400 ). Upon cooling of the melt, the melt of the molding combines with the paint of the printed image to form a one-piece component. In the course of the molding is cooled in the usual way (step 500 ), the tool is opened (step 600 ) and the molded part taken along with the decorative or typeface print (step 700 ). Possibly. For example, after removal of the finished molded part, the area in which a decorative or typeface imprint is to take place for the next molded part can be tempered by means of suitable tempering devices to temperatures suitable for printing image application. As a result, a pre-hardening and / or curing of the introduced pressure medium (paint / color) can be achieved. Such curing can also be effected by UV radiation.

At the The method according to the invention is of special importance Advantage that it is now possible for the first time by means of an integration of a decoration directly into the injection molding process in a simple way individual plastic parts with lot size 1 inexpensive to produce. in this connection has proven especially that the decorative or typeface by means of a print head directly on the tool cavity and then apply the resulting "image layer" to inject. Thus, comparable to a office printer the design of the individual print job each individual molding be assigned directly and changed from molding to molding become. Likewise, additional information, logos, Serial or production numbers, customer names or the like directly on the molding.

The inventive principle is not left, when the pressure in the open tool is on a slide and the Foil is back-injected in the manner of a transfer decoration. in this connection the film serves as a release agent for Werkzeugkavität. It is just as possible, the printed film also on the molding leave so that they may scratch protection layer forms for the molding. Especially at high melt temperatures and component geometry related high shear loads in the printed Range is also conceivable that the decorative or typeface on the Tool cavity is applied directly and a foil is applied between the printed image and the molding to a flow of the printed image to avoid. A connection between the pressure, the protective film and the molded part is found during cooling Injection molding by temperature and pressure instead.

Especially the management of printheads using industrial robots enables printing on deep cavities (eg cup walls or cup bases). by virtue of the stamp-like printing technique of a pad printing can by means of This method also a relatively deep geometry to be printed. However, a pad printing process is limited suitable for creating individual print images. For example a variety of print images could be generated in the appropriate pad printing stamp on a revolver, d. H. one Stamp turrets are provided, with certain plunger be selected and used by machine.

Farther is in the invention of particular advantage that a perfect free, individual decor or typeface choice for each individual molding is feasible in any order, because a control of the printing process over a usual Personal computer is possible. This results in lower Logistics requirements, as only a small storage for custom parts is required. In addition, reaction times shortened to special customer requirements.

If possible, a mobile phone tray with a personal photo or a personal graphic representation or also of individualizable inventory codes of commercially used devices, eg. B. mobile phones. Another advantage of the invention It is He that the process in a simple and cost-effective manner in existing plant technology based on a multi-component system is possible. In addition, offers the Invention, the printing ink or the print matrix (the printing medium) to impart additional properties in which, for example, electrically conductive paint for the production of heatable parts or so-called LCD colors are added, by means of which, in response to an electrical signal, the molded parts produced or darken again are transparent switchable.

Farther can the printing ink after applying the pressure by means of a Lasers are structured, as is common in the production of prototypes is. Increases the resulting miniature grid on the component the interaction at the interface between the printed image and the molded part, so that on the one hand a defined refraction of Light for the production of anti-reflective parts possible or a higher mechanical bond between the print image and the molding is achievable.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• EP 1115547 B1 [0002]
• DE 102004050290 A1 [0003]

Claims (25)

A method for producing molded parts with an openable and closable tool, wherein a flowable raw material in the tool receives a desired shape and is then cooled, characterized in that prior to introduction of the flowable raw material at least on a portion of a forming portion of the opened tool, ie On a portion of the mold cavity by means of a printing process a decorative or typeface is connected in a molding process with the flowable raw material and is applied, wherein the applied decorative or typeface image is firmly and inseparably connected to the molding after cooling the flowable raw mass. Method according to claim 1, characterized in that that the printing process is a customizable printing process, z. As an ink-jet printing method, a thermal transfer printing method or is a pad printing method. Method according to claim 1 or 2, characterized that the printing process performed computer-aided becomes. Method according to one of the preceding claims, characterized in that the decorative or typeface an individual and is a unique pattern or a pictogram. Method according to one of the preceding claims, characterized in that the decorative or typeface image is a serial number, a lot number or otherwise identifying the molding Code is. Method according to one of the preceding claims, characterized in that the flowable raw mass plasticized plastic or plastic melt is. Method according to one of the preceding claims, characterized in that the method is a plastic injection molding process or a plastic transfer molding process. Method according to one of the preceding claims, characterized in that the decorative or typeface on a is applied in the tool carrier medium. Method according to one of the preceding claims, characterized in that the carrier medium of a tool wall adapted at least in the partial area of the shaping section and is on this adjacent film. Method according to one of the preceding claims, characterized in that the carrier medium is a textile Fabric, a carpet or leather is. Method according to one of the preceding claims, characterized in that a print head by means of a robot during the printing process corresponding to the tool surface is moved at a constant distance to this. Method according to one of the preceding claims, characterized in that the decorative or typeface character and / or image representation. Method according to one of the preceding claims, characterized in that as the printing medium for the production of the decorative or typeface acrylic lacquers, in particular on the basis of PMMA (polymethyl methacrylate) can be used. Method according to one of the preceding claims, characterized in that the carrier medium after the Forming process remains in the tool and the decorative or typeface of a previous production cycle completely from the Carrier medium is replaced. Method according to one of the preceding claims, characterized in that the carrier medium with the molded part firmly connected and as a scratch protection for its surface serves. Method according to one of the preceding claims, characterized in that at elevated, expected Pressure and / or shear stress in the shaping process the decorative or typeface directly on the section of the tool (the tool cavity) is applied and covered with a protective film. Method according to one of the preceding claims, characterized in that by pressure and temperature influence the decorative or typeface with the protective foil and the protective foil is connected to the molding. Method according to one of the preceding claims, characterized in that the decorative or typeface image is multicolored is trained. Method according to one of the preceding claims, characterized in that the pressure medium acts as a release agent. Method according to one of the preceding claims, characterized in that the De kor- or typeface is a wood, aluminum or other surface replica. Method according to one of the preceding claims, characterized in that the printing medium is an electrically conductive Color is. Method according to one of the preceding claims, characterized in that the molded part is a heatable molded part, z. B. a mirror support or a vehicle window is. Method according to one of the preceding claims, characterized in that the print medium is an LCD color, so that printed areas of the molded part can be controllably darkened. Method according to one of the preceding claims, characterized in that the printing medium structured by means of laser becomes. Method according to one of the preceding claims, characterized in that the method according to a or more of the preceding claims is part of one More component injection molding is, being first in a first step, a transparent surface layer (first Component) is generated, then the cooled transparent surface layer by means of the invention The method of claim 1 to 24 is printed and then another part (second component) formed, z. B. molded becomes.