DE102020127316A1 - Process for producing a composite component, composite component and tool for producing a preform component of a composite component - Google Patents

Abstract

A method for producing a composite component (60) comprises the method steps: a. Preforming a limp component (40) into a less limp preform component (42), b. Back injection molding or back injection embossing of the preform component (42) with a plastic.

Description

The invention relates to a method for producing a composite component, a composite component produced using the method, and a tool for producing a preformed component of the composite component.

Composite components are known in principle in various technical fields. Composite components often consist of two or more components. In particular, composite components can be designed as lightweight components or also have a three-dimensional shape that shows a certain stability. For this purpose it is known to use plastic back-injection techniques. For example, decorative materials such as selected foils, textiles or leather can be back-injected with plastic. These processes are often limited by the mechanical and thermal sensitivity of the decorative material to be back-injected. Another disadvantage is the slow dissipation of heat from the molded part via the decorative material. In order to counteract these limitations, combinations of back-injection technology and low-pressure injection molding or thermoplastic foam injection molding are often used. These processes are gentler on the decorative material, since they enable a flat and homogeneous distribution of pressure and lead to less distortion in the components. The decorative material is fed to the injection molding machine as a flat element and given its final shape by the pressure of the back-injection process. However, this principle usually only works with very simple geometries or flat surfaces and insensitive decorative materials.

An injection molding process usually takes 20 to 70 seconds, with the actual injection process taking 1 to 5 seconds. Pressures in the range of 200 to 1500 bar at a temperature of 180 to 320 °C are used. The high pressures and temperatures and the short injection time put a strain on the decorative material and limit the range of decorative materials that can be used and the possible geometries.

The object of the present invention is to provide a production method with which a composite component can be produced in a material-friendly manner. A further object of the invention is to provide a corresponding composite component.

1. a) Vorformen eines biegeschlaffen Bauteils zu einem weniger biegeschlaffen Vorformbauteil;
2. b) Hinterspritzen oder Hinterspritzprägen des Vorformbauteils mit einem Kunststoff.

This object is achieved according to the invention by a method for producing a composite component with the method steps:

1. a) Preforming a limp component into a less limp preform component;
2. b) back-injection molding or back-injection embossing of the preformed component with a plastic.

If the limp component, for example a component made of textile, leather, plastic or film, is preformed and the resulting preformed component is fed into an injection mold, lower pressures are required for back-injection compression molding in order to back-inject the resulting preformed component. The method according to the invention is therefore gentler on the material than the known methods. This means that other materials can be used than in the conventional production of composite components. The limp components can be decorative materials, but they can also have additional or alternative properties. In particular, the limp components in the finished composite element can fulfill additional functions than those of a pure decorative element.

Due to the fact that a less pliable preform component is initially produced, wrinkling during back injection can be avoided if back injection-compression molding technology is used. Problems with the formation of wrinkles arise when flat, flexible materials are conventionally back-injected.

In this case, back injection can take place in two stages, for example, with plastic first being introduced at a lower pressure into an open or opening injection mold and then the injection molding compound being distributed at low pressure by means of a stamping stroke of the mold stamp. Towards the end of the embossing stroke, it is necessary to apply greater holding pressure to the cavity. At this point in time, the preform component is fixed by the already partially sealed or frozen plastic to such an extent that there is no risk of further stress on the preform component due to the increased pressure. As a result, warping of the preform component during the back-injection process is largely ruled out.

The preforming can preferably be carried out under the action of heat. A pliable component, which has plastic or is made of plastic, becomes more easily deformable by heating. Upon subsequent cooling, the molded part retains its shape, resulting in a more or less rigid or stiff preform component. If the limp component has natural fibers, such as felt, wool or flax, a chemical and/or physical reaction can be triggered under the influence of heat, which also means that the limp component that has been shaped largely retains its shape after cooling.

Back injection can take place in an injection molding tool. A combination of injection molding and embossing is carried out in such a tool, which can be carried out at lower pressures in a particularly gentle manner for the preformed component.

The limp component can be impregnated with a plastic. If a limp component impregnated with plastic, for example ABS, is deformed when heated, the plastic solidifies after cooling and the preformed limp component largely retains its shape, resulting in a preformed component that is less limp than the original limp component.

The preform component can in particular be trimmed with a laser. In this way, the preformed component can be brought to its desired shape or outer contour before it is placed in the injection-compression molding tool. For trimming, the preform component can be clamped in a holder so that it does not change its position during trimming.

A heat conductor can be applied, in particular embroidered, to the limp component before the deformation. This makes it possible to later heat the composite component produced. It is particularly advantageous if the heating conductor is embroidered. As a result, the heating conductor has a certain mobility relative to the limp component and can follow the contours of the limp component or the preform component produced during the deformation without damaging the heating conductor. In particular, the heating conductor can be attached to the limp component by means of a thread or a defined sewing geometry, with the fixing by means of thread allowing the heating conductor to be movable relative to the limp component. As a result, mechanical stress on the heating conductor can be avoided.

The heating conductor can preferably be attached to the flexible component in a loop or meander shape by means of a sewing geometry.

In the case of back injection molding, injection molding compound can first be introduced into the injection molding tool while the injection molding tool is still partially open, and then the injection molding tool can be closed. Due to the fact that the injection molding tool is initially partially open, the injection cake can be introduced with a low pressure of, for example, about 50 bar. This prevents damage to the preform assembly. When the injection cake has been introduced, the injection molding tool can be closed further. The spritz cake fills the remaining spaces. The cavity in the injection molding tool can be completely ejected and shrinkage compensated for by applying appropriate pressure to an injection nozzle. As the injection stamping tool closes, the preform component is pre-fixed by the injection cake and the expanding flow front of the plastic material, making it possible to subsequently work with a higher holding pressure without deforming or damaging the preform component.

A three-dimensional composite component, which can be produced by the method according to the invention, also falls within the scope of the invention. The three-dimensional composite component has a preformed component formed from an originally pliable component and a plastic carrier to which the preformed component is attached. In particular, the preformed component is back-injected with the plastic of the plastic carrier and connected by means of the back-injection stamping technique. The originally limp component connected to the plastic carrier is, of course, no longer limp, but reinforced by cross-linking with the plastic carrier.

Particular advantages result when the preform component is attached to the plastic carrier without adhesive. This prevents adhesives from evaporating later. Nevertheless, the composite component according to the invention has a better bond or crosslinking between the pliable component or preformed component and the plastic carrier than conventional composite elements.

The preform component can be designed as a textile, in particular as a felt, woven fabric, knitted fabric, nonwoven fabric or warp-knitted fabric. If the preform component forms the visible surface of the composite component, different decorative layers can be realized in this way. The preform component can have plastic and/or carbon. If the pliable component has plastic or is made of such a material, for example made of polyester, the pliable component can be preformed under the action of heat without any problems, resulting in a preformed component that can then be further processed using back-injection or injection-compression molding technology.

If the preform component has carbon, in particular is designed as a woven fabric made of carbon, a composite part can be formed which can absorb forces particularly well. Such a composite component is very stable with a low weight. It can be used, for example, in vehicles as collision protection. The layer originally made of limp material, it therefore has additional functional properties than a purely decorative function. In particular, the preformed component can have a carrier, in particular a textile carrier, on which fiber fabrics are arranged. The fiber layer can be fiber strands, for example made of carbon fibers, which are fixed to the carrier by means of a sewing or embroidery technique. The preform component and thus the composite component can be locally reinforced in a targeted manner by the fiber strands. In particular, the fiber strands can be arranged according to the load. The fiber strands can be laid in several layers and crossing one another.

Alternatively, the preform component may comprise a natural fiber such as flax.

The composite component can have a heating conductor. For example, a heating conductor can be woven or knitted into the originally flexible component. Alternatively, it is conceivable that the heating conductor is arranged in a loop or in a meandering manner on the preformed component, in particular is embroidered.

If the limp component is designed as a fabric, it can be woven, for example, in such a way that mechanically stressed areas are reinforced. For example, tensile forces can be absorbed by a fabric, while compressive forces can be absorbed by the plastic carrier. A particularly stable composite component can be realized in this way.

If the composite component has a heat conductor, a multifunctional component is created. Such components can be used particularly advantageously in the automotive industry. In particular, interior elements can be designed as infrared radiators. Such composite components can also be used in other areas, such as in buildings, for seats in sports stadiums or for office equipment. The use of a heating conductor has the advantage that flexible heating is possible. The heater can react quickly. The heat output can be transferred and controlled much more effectively than with other heat sources. This saves energy. The heat can be given off directly to objects and not to the air. This can reduce heat loss. Infrared heat or radiant heat does not require air circulation and is therefore noiseless. Infrared heat is also felt to be particularly comfortable.

Particular advantages result when such a composite component is used in an electric vehicle. Vehicles with electric drive have no waste heat from a cooling system due to the lack of a combustion engine. There is also a requirement to keep the power consumption of assistance systems, such as heating and air conditioning, as low as possible. If convection heating is not used and a more effective heating can be used instead, the battery of an electric vehicle is less heavily loaded, which has a positive effect on the range of an electric vehicle.

Furthermore, it is possible to design control elements, for example of a municipal vehicle, to be heatable, in that at least part of the control element is formed by a composite component according to the invention with a heating conductor. Other vehicle components can also be formed using a heatable composite component, such as an armrest, a center console, a door center panel, etc. Ceiling or floor elements of buildings can also be formed using a multifunctional composite component.

The heating conductor can be arranged in a corner area or an edge area of the composite component. This is possible because the heating conductor can already be arranged on the limp component before the production of the composite component and is not damaged during the back injection molding of the limp component or the preform component formed therefrom.

The composite component can have a sensor. This makes it possible, for example, to use the composite component to construct or supplement a bumper of a vehicle with distance sensors, thereby creating an improved distance sensor system. The flexible component can be made of carbon fibers, for example, in order to improve the stability of the bumper locally or over a large area. The heat conductor can be used to heat in a targeted manner in the area of the sensors, so that the sensors can be prevented from icing up and the functionality of the sensor can be ensured even in frost.

Further advantages arise when the composite component has at least one operating element. For example, the composite component can have a button. This offers advantages when the composite component is used as a joystick on a machine. In addition, if the composite component is used, for example, as a door element of a vehicle, it can have switches for opening and closing windows.

Furthermore, it is conceivable to combine the composite component on the side of the preformed component with a further layer, for example a TPE layer or a rubber-like thermoplastic for a floor of a vehicle stuff to coat. A charging cradle for a mobile terminal device can also be designed in this way.

The scope of the invention also includes a drawing/embossing tool for producing a preform component from a limp component, with a punch and a die that can be moved relative to one another, and a receptacle for receiving the limp component. With such a tool, a relatively dimensionally stable preformed component can be produced from a pliable component, which preformed component can then be used in an injection molding tool for back injection molding with plastic.

The receptacle can be designed in the form of a plate and have a through-opening in the area of which the limp component can be arranged. The pliable component can therefore be arranged flat in the area of the through-opening. The die and punch can then be brought together and enclose and deform the limp component between them. The mount for the flexible component prevents creases from forming during deformation.

The recording can represent a height-adjustable drawing plane. It cannot be movable relative to the die and can clamp the limp component.

The stamp and/or the die can be heatable. As a result, the shaping and production of a preformed component can be implemented in a particularly simple manner. For this purpose it is advantageous if the pliable component has natural fibers or plastic. For example, the limp component can be coated with plastic or impregnated with plastic. The heating can take place via a heating circuit in the punch and/or in the die.

Further features and advantages of the invention result from the following description of exemplary embodiments of the invention, with reference to the figures of the drawing, which show details essential to the invention, and from the claims.

• 1 eine teilweise geschnittene Explosionsdarstellung eines Werkzeugs zur Erstellung einer Vorform;
• 2 eine Schnittdarstellung durch das Werkzeug gemäße der 1 mit eingelegtem biegeschlaffem Bauteil;
• 3 eine Schnittdarstellung durch das Werkzeug gemäß 1 im geschlossenen Zustand;
• 4 eine Ansicht eines Vorformbauteils;
• 5 eine Schnittdarstellung eines Hinterspritzprägewerkzeugs;
• 6 eine Ansicht eines Verbundbauteils;
• 7 eine Schnittdarstellung des Verbundbauteils.

Show it

• 1 a partially sectioned exploded view of a tool for creating a preform;
• 2 a sectional view through the tool according to the 1 with inserted flexible component;
• 3 a sectional view through the tool according to FIG 1 when closed;
• 4 a view of a preform component;
• 5 a sectional view of an injection molding tool;
• 6 a view of a composite component;
• 7 a sectional view of the composite component.

the 1 shows a tool 10 for producing a preformed component from a flexible component. For this purpose, the tool 10 has a stamping plate 12 with a stamp 14 arranged thereon. The punch 14 can interact with a die 18 arranged on a die plate 16 . A plate-shaped receptacle 20 is provided to accommodate the flexible component. The stamp plate 12, the receptacle 20 and the die plate 16 are guided along guides 22. The movement of the die plate 16 relative to the stamp plate 12 takes place via a cylinder 24. The reference number 26 designates pressure control valves. Different shims 28 installed in the socket 20 can be used depending on the thickness of the pliable component. The receptacle 20 has a through-opening 30 through which the plunger 14 protrudes. A flexible component to be deformed can be placed on the receptacle 20 in the area of the through-opening 30 . The receptacle 20 has a depression 32 for this purpose.

The representation of 2 it can be seen that a limp component 40 was arranged over the through-opening 30 on the receptacle 20 . In the state shown, the limp component has a flat, planar configuration, also referred to as a drawing plane.

Of the 3 It can be seen that the punch plate 12 and the die plate 16 were then moved towards one another, so that the pliable component 40 is arranged between the punch 14 and the die 18 and was deformed. In this case, the punch 14 and/or the die 18 can be heated. Under the influence of heat and subsequent cooling, the pliable component 40 retains its shape, so that a preformed component 42 is formed.

Such a preform component 42 is in the 4 shown. In this case, the preform component 42 is produced from a flexible component in the form of a fleece. The preform component 42 has a heating conductor 44 here, which is laid in the form of waves and loops. The heating conductor 44 has already been applied to the limp component 40 before it is deformed, in particular fastened to the limp component 40 by means of embroidery. It can be seen that the heating conductor 44 also extends into edge regions 46 of the three-dimensional preformed component 42 . Subsequently, the preformed component 42 can be cut into shape, for example by means of a laser, so that it can be inserted with a precise fit into an injection molding tool.

An injection stamping tool 50 is the 5 shown. The injection stamping tool 50 has a first mold part 52 which is designed in accordance with the shape of the preform component 42 . As a result, the preform component 42 can be inserted into the mold part 52 . A distance is initially left between the first mold part 52 and a second mold part 54, ie the injection-compression molding tool 50 is not completely closed. If the injection molding die 50 is not completely closed, injection molding compound is introduced into the intermediate space between the two mold parts 52, 54 at a pressure in the range of approximately 50-100 bar via a hot runner with needle valve 56. This creates a spray cake on the rear side of the preform component 42. The mold parts 52, 54 can then be moved further towards one another, so that the cavity between the two mold parts 52, 54 is reduced and the spray cake is distributed in the cavity between the two mold parts 52, 54 and comes into contact with the preform component 42 over the entire surface. The internal pressure in the cavity increases towards the end of the embossing stroke to approx. 100-150 bar. Exchangeable spacer plates 58 can be used to set how far the injection molding tool 50 can be closed.

The introduction of the injection cake with low pressure prevents damage to the preform component 42. When the injection molding die 50 is closed, a corresponding holding pressure can be introduced and the cavity between the mold parts 52, 54 can be completely filled with injection molding material, in particular plastic, to compensate for the material shrinkage. After a cooling time has elapsed for the injection molding material to solidify, the injection molding stamping tool 50 can be opened and a composite component that has now been obtained can be removed. The removal of the composite component as well as the loading of the injection molding tool 50 with the preformed component 42 can be carried out manually or by means of robots.

the 6 shows a composite component 60 with a carrier 62 formed from the injection molding compound, in particular made of plastic, and the preformed part 42, which was produced from the pliable component 40. In the 6 is the preform part 42 seen from the other side compared to 4 . Connections 64, 66 for the heating conductor 44 can be seen here.

the 7 shows a sectional view through the composite component 60. It can be seen here that the preformed component 42 is back-injected with the injection molding material and there is a positive connection between the preformed component 42 and the carrier 62.

Claims (19)

Method for producing a composite component (60) with the method steps: a. Preforming a limp component (40) into a less limp preform component (42), b. Back injection molding or back injection embossing of the preform component (42) with a plastic. procedure after claim 1 , characterized in that the preforming takes place under the action of heat. Method according to one of the preceding claims, characterized in that the back injection takes place in an injection molding tool (50). Method according to one of the preceding claims, characterized in that the pliable component (40) is impregnated with a plastic. Method according to one of the preceding claims, characterized in that the preform component (42) is trimmed, in particular with a laser. Method according to one of the preceding claims, characterized in that a heating conductor (44) is applied, in particular embroidered, to the flexible component (40) before the deformation. Method according to one of the preceding claims, characterized in that when back-injecting, injection molding compound is first introduced into the injection molding tool (50) with the injection molding tool (50) still partially open and then the injection molding tool (50) is closed. Three-dimensional composite component (60), in particular produced in a method according to one of the preceding claims, with a preformed component (42) formed from a pliable component (40) and a plastic carrier (62) to which the preformed component (42) is attached. Composite component, characterized in that the preformed component (42) is attached to the plastic carrier (62) without adhesive. Composite component according to one of the preceding claims, characterized in that the preform component (42) is designed as a textile, in particular as a felt, woven fabric, knitted fabric, fleece or warp-knitted fabric. Composite component according to one of the preceding claims, characterized in that the preformed component (42) has plastic, a natural fiber and/or carbon. Composite component according to one of the preceding claims, characterized in that the composite component (60) has a heating conductor (44). Composite component according to one of the preceding claims, characterized in that the heating conductor (44) is arranged in a loop or in a meandering manner on the preformed component (42). Composite component according to one of the preceding claims, characterized in that the heating conductor (44) is arranged in a corner region or an edge region of the composite component (60). Composite component according to one of the preceding claims, characterized in that the composite component (60) has a sensor. Composite component according to one of the preceding claims, characterized in that it has at least one operating element. Tool (10) for producing a preform component (42) from a limp component (40), with a punch (14) and a die (18) which can be moved relative to one another, and a receptacle (20) for receiving the limp component ( 40). tool after Claim 17 , characterized in that the receptacle (20) is plate-shaped and has a through-opening (30), in the region of which the limp component (40) can be arranged. Tool according to one of the preceding claims, characterized in that the punch (14) and/or the die (18) can be heated.

Images