DE102018129319A1 - Method of manufacturing a thermoformed composite component - Google Patents

Abstract

The invention relates to a method for producing a thermoformed composite component from a thermoformable semifinished product (11) and at least one insert element (12). In the method, a semifinished product (11) is heated to a forming temperature and is applied to the surface of a provided insert element (12) facing the semifinished product (11) by applying underpressure and / or overpressure, as a result of which the respective application is applied to the Form the required degree of deformation of varying wall thicknesses (16). To produce a thermoformed composite component (10) with essentially uniform wall thicknesses (19), the insert element (12) has varying wall thicknesses (18).

Description

The invention relates to a method for producing a thermoformed composite component from a semifinished product and at least one insert element, the semifinished product being heated to a shaping temperature and the heated semifinished product applying pressure to the surface of the insert element facing it, and a Composite component produced by this method with an essentially uniform wall thickness.

The manufacture of thermoformed composite components is, for example, from the international patent application WO 02/072325 A1 known. In this case, a thermoformable semi-finished product is heated and pulled over or molded onto a tool or an insert or carrier element. Such insertion or support elements can be used, for example, to reinforce the composite component and / or integrate functional elements into it, such as reinforcements, fastening devices or the like.

Depending on the geometry to be imaged, the thermoformable semi-finished product is sometimes deformed to a great extent during thermoforming, which results in a decrease in the wall thickness in these areas. Since the semi-finished product deforms non-uniformly depending on the geometry of a tool or insert element, the wall thickness of the thermoformed semi-finished product also varies unevenly. This leads to an inhomogeneous wall thickness distribution of the semi-finished product and thus also of the component. This results in technical disadvantages such as poor power flow, reduced dimensional stability and also traces of deformation and thus optical deficits in the surface of such composite components.

Proceeding from this, the object of the invention is to propose an improved method for producing thermoformed composite components, which in particular have an essentially uniform wall thickness. This is achieved according to the invention by the teaching of the independent claims. Advantageous embodiments of the invention are the subject of the dependent claims.

• - Bereitstellen des thermoformbaren Halbzeugs;
• - Bereitstellen des wenigstens einen Einlegeelements;
• - Erwärmen des Halbzeugs auf eine Umformtemperatur;
• - Umformen des Halbzeugs durch Aufbringen von Unterdruck und/ oder Überdruck auf das erwärmte Halbzeug, wobei sich das Halbzeug an die ihm zugewandte Oberfläche des Einlegeelements anlegt und abhängig von dem jeweils zum Anlegen an die Oberfläche erforderlichen Umformgrad variierende Wandstärken ausbildet.

Um ein thermogeformtes Verbundbauteil mit im Wesentlichen gleichmäßigen Wandstärken herzustellen, weist das Einlegeelement variierende Wandstärken auf, welche die sich beim Umformen ausbildenden variierenden Wandstärken des Halbzeugs im Wesentlichen ausgleichen, so dass sich beim Umformen ein Verbundbauteil mit im Wesentlichen gleichmäßigen Wandstärken ausbildet.To achieve the object, a method for producing a thermoformed composite component from a thermoformable semi-finished product and at least one insert element is proposed, with the following steps:

• - Providing the thermoformable semi-finished product;
• - Providing the at least one insert element;
• - Heating the semi-finished product to a forming temperature;
• - Forming the semifinished product by applying negative pressure and / or excess pressure to the heated semifinished product, the semifinished product contacting the surface of the insert element facing it and forming varying wall thicknesses depending on the degree of deformation required to apply it to the surface.

In order to produce a thermoformed composite component with essentially uniform wall thicknesses, the insert element has varying wall thicknesses which essentially compensate for the varying wall thicknesses of the semifinished product that are formed during the forming, so that a composite component with essentially uniform wall thicknesses is formed during the shaping.

In a further process step, the composite component produced in this way can be cut to a desired shape.

The proposed method can be used to produce composite components with essentially uniform wall thicknesses, which have improved properties compared to composite components produced using known methods. The more uniform wall thicknesses achieved with the process result in an improved flow of force in the composite component and increased component rigidity. In addition, an increased dimensional accuracy of the composite components is achieved. The method also reduces optical deficits in surface appearance on visible surfaces, such as flow lines, which also result from uneven wall thicknesses.

In the first process step, a thermoformable semi-finished product is provided. Suitable thermoformable semi-finished products are, for example, films or sheets made of a thermoformable plastic, such as, in particular, a thermoplastic. Plastics frequently used for thermoforming are polypropylene (PP), polystyrene (PS), acrylonitrile-butadiene-styrene (ABS), polycarbonate (PC), or polyvinyl chloride (PVC). In addition, many other materials for producing a thermoformed composite component can be used with the proposed method, such as thermoformable synthetic leather, which have, for example, a textile base support and a suitable plastic cover layer. Other hot-formable materials, such as glass, are also suitable for thermoforming. The semi-finished product used can already have a geometry that is adapted to the composite component to be produced, or can be cut to size accordingly only after the actual production of the composite component.

In a further method step, at least one insert element is provided. Dependent the composite component to be produced can also have more than one insert element. Such an insert element can be made of the same or similar material as the semi-finished product itself, from which components with particularly homogeneous component properties can be produced. In the same way, such insert elements can also be made of a different material from the semi-finished product, for example in order to provide desired properties of the composite component produced. For example, the insert element can be formed from a plastic or a metal in order to provide the desired properties for the composite component.

In the next process step, the semi-finished product is heated to a forming temperature at which the semi-finished product can be applied to the at least one insertion element or tool with the application of lower forces.

In the next process step, the semi-finished product is formed by applying negative pressure and / or positive pressure to the heated semi-finished product. By applying a vacuum and / or overpressure to the semi-finished product, it is moved in the direction of the insert element. Thus, an overpressure is applied to the side of the semi-finished product opposite the insert element and a negative pressure is applied to the side of the semi-finished product facing the insert element. a negative or positive pressure is usually applied by means of a flow of additional air or by means of the application of a suction or so-called vacuum in a corresponding area. Due to the forces exerted on the semi-finished product by the vacuum or overpressure, the semi-finished product rests on the surface of the insert element facing the semi-finished product while being deformed simultaneously. The required degree of deformation results from the geometry of the insert element, so that depending on this, varying wall thicknesses of the semi-finished product are formed. In the context of the invention, stretching of the semifinished product is referred to as forming, in which the wall thickness of the semifinished product is reduced. Basically, it is also possible to compress the semi-finished product and thus increase the wall thickness. This usually only occurs in narrowly limited areas, so that an increase in the wall thickness is not taken into account in the illustration of the invention, although this can of course also be taken into account in the proposed method analogously to the stretching of the semi-finished product.

In order to produce a composite component with essentially uniform wall thicknesses, the use of an insert element with varying wall thicknesses is proposed. Such an insert element has a greater wall thickness in the areas where the semi-finished product is subjected to a greater deformation and therefore has a smaller wall thickness. The insert element forms the desired, uniform wall thickness together with the semi-finished product. In those areas where the semi-finished product is exposed to a smaller deformation and therefore has a larger wall thickness after the deformation, smaller wall thicknesses are provided on the insert element, so that this, together with the semi-finished product, also forms the desired, uniform wall thickness here. In areas in which the semifinished product is subjected to an average deformation, the insert element also has an approximately average wall thickness in order to likewise form the desired, uniform wall thickness. The insert element can be made from a material with the same or similar properties as the semifinished product, or from a material with different, predetermined properties in order to produce a composite component with certain intended properties.

Due to the interaction of the wall thicknesses of the semifinished product and the insert, which vary due to the shaping of the semifinished product, a composite component with substantially uniform wall thicknesses is formed by the proposed method. The wall thickness of the composite component is therefore referred to in the present case as “substantially uniform” since, depending on the embodiment of the composite component, areas can also be provided in which a greater or lesser wall thickness of the composite component is desired or required.

In one embodiment of the method for producing a thermoformed composite component, the varying wall thicknesses of the formed semifinished product that form when it is applied to the surface of the insert element are determined by a simulation method and the wall thicknesses and in particular its distribution on the insert element are determined depending on the simulation results. This method step can in particular form a sub-step of the method step “providing the at least one insert element”. The simulation method is used in particular to calculate the degree of deformation of the semi-finished product in the areas in which it rests on an insert element in the finished composite component; Accordingly, the wall thickness of the semi-finished product at any desired position of the semi-finished product or the insert element is determined in this way. The varying wall thicknesses of the semi-finished product are thus available. From these simulation results, the varying wall thicknesses of the at least one insert element, in particular for producing a desired, essentially uniform wall thickness, can then be determined for the composite component.

In one embodiment of the method, the insert element is produced using an additive manufacturing method or using an original molding method. For composite components with smaller quantities in particular, individually shaped insert elements with varying wall thicknesses can be produced using an additive manufacturing process. The possibility of deriving the geometry of an insert element directly from results of a forming simulation of the semi-finished product is also advantageous. Additive manufacturing processes also make it possible to manufacture insert elements from a large number of suitable materials. For example, a composite component produced using the proposed method can have component properties that cannot be readily represented by a “one-piece” thermoformed component itself.

An additional advantage when using an additive manufacturing method for producing an insert element is the possibility of attaching various functional structures, which in particular cannot easily be provided on components produced using a conventional thermoforming method, such as, for example, fastening devices such as snap hooks, undercuts or the like. In addition, a structured surface of an insert element produced using this method is advantageous for producing a composite component produced using a thermoforming method. The structure resulting from additive manufacturing processes is usually well suited for establishing a suitable connection between an insert element and a semifinished product formed thereon.

The insert element can in particular also be produced for composite components with larger quantities using a master molding process such as a casting process. In particular, insert elements made of plastic or a light metal can be produced inexpensively, for example by means of an injection molding process. Results from the forming simulation of the semi-finished product can also be used for primary molding processes, in particular for producing the casting mold.

In one embodiment of the method, the insert element has at least air-permeable areas. Such air-permeable areas are particularly expedient if the semifinished product is formed on the insert element by means of negative pressure during the shaping in order to remove the air located between the semifinished product and the insert element through the insert element. For example, the formation of air-filled cavities between the semi-finished product and the insert element can be avoided. Such an air-permeable area can have one or more in particular small openings or a type of perforation with a large number of small openings such as bores or slots. The possible cross section of such openings is, however, limited to a few tenths of a millimeter if it is undesirable to mark the openings on the surface facing away from the insert element.

In one embodiment of the method, the surface of the insert element facing the semifinished product is structured. A structured surface favors the formation of a good connection between the insert element and the semifinished product formed thereon, in particular by adhesion. In addition, a structured surface also favors the escape of air from the space between the insert element and the semifinished product during the connection between the insert element and the semifinished product, in order to avoid the formation of air-filled cavities between the semifinished product and the insert element.

In one embodiment of the method, when the at least one insert element is provided, a mediator layer is applied to the surface of the insert element facing the semi-finished product. Such a mediator layer forms a suitable surface on the insert element which is suitable for establishing a good connection to the surface of the semifinished product and thus for establishing a good connection between the insert element and semifinished product.

In one embodiment of the method, the insert element has undercuts, at which a positive connection with the semi-finished product is produced by the reshaping of the semi-finished product at the undercuts. These undercuts are designed so that the semifinished product engages behind the insert element when it is formed.

In a further aspect, a composite component is proposed to solve the problem, which is made from a thermoformable semi-finished product and at least one insert element, in particular with a method that has one or more aspects of the preceding description. The at least one insert element has varying wall thicknesses, which essentially compensate for the wall thicknesses of the semifinished product, which are formed by thermoforming, in the region of the at least one insert element, so that the composite component has a substantially uniform wall thickness.

The proposed composite component is with a method according to one or more aspects of the preceding description producible. Accordingly, this composite component then also has one or more of the features and properties described with respect to the method for producing the thermoformed composite component.

• 1 eine schematische Darstellung des Ablaufs eines Verfahrens zum Herstellen eines thermogeformten Verbundbauteils gemäß dem Stand der Technik; und
• 2 eine schematische Darstellung des Ablaufs eines beispielhaften erfindungsgemäßen Verfahrens.

Further features, advantages and possible uses of the invention result from the following description in connection with the figures. It shows

• 1 a schematic representation of the sequence of a method for producing a thermoformed composite component according to the prior art; and
• 2nd a schematic representation of the sequence of an exemplary method according to the invention.

1 shows a schematic representation of the sequence of a method for producing a thermoformed composite component according to the prior art. In the top illustration A is a provided thermoformable semi-finished product 11 shown in the form of a plate made of a thermoformable plastic and a provided insert 12 , which is made of a non-thermoformable plastic. The insert element 12 has one essentially, ie apart from the molded elements 22 uniform wall thickness 14 on. Also the semi-finished product provided 11 has an even wall thickness 13 on. Above the semi-finished product 11 is a heater 20th for heating the semi-finished product 11 arranged at a forming temperature.

Instructs the semi-finished product 11 a corresponding forming temperature, this is formed by applying negative pressure and / or positive pressure. The movement of the semi-finished product 11 to the insert element 12 gone in 1 through the arrows 15 represented symbolically. The semi-finished product lays down during the forming process 11 to the surface of the insert element facing him 12 and forms with the insert element 12 a composite component 10th from which in the middle representation B in 1 is shown. As in the illustration B is clearly recognizable, is formed depending on the degree of deformation of the semi-finished product required for application to the surface 11 varying wall thicknesses 16 out.

In a further process step, the composite component designed in this way can 10th can be cut to a desired shape in the illustration C. is shown. There you can also see that the wall thickness 17th of the composite component produced by the known method 10th depending on the degree of deformation of the semi-finished product 11 varies. So is the wall thickness 17th in the center of the composite component 10th larger than at the edges of the composite component 10th . This results from the low degree of deformation of the semi-finished product 11 in the central area of the composite component 10th trained spherical shape in contrast to the high degree of deformation of the semi-finished product 11 in the side area of the spherical shape, where there is a large stretch of the semi-finished product 11 is required to attach this to the insert 12 to create.

2nd shows a schematic representation of the sequence of an exemplary method according to the invention, with which composite components 10th with an even, homogeneous wall thickness 19th are producible. In the top illustration A is also in 2nd a provided thermoformable semi-finished product 11 , shown for example in the form of a plate made of a thermoformable plastic and a provided insert 12 , which is made for example from a non-thermoformable plastic. The insert element 12 exhibits varying wall thicknesses 18th on. The semi-finished product provided 11 has a uniform wall thickness in the exemplary method shown 13 on. Above the semi-finished product 11 is a heater 20th for heating the semi-finished product 11 arranged at a forming temperature.

Is the semi-finished product 11 heated to a corresponding forming temperature, this is formed by applying negative pressure and / or positive pressure. The movement of the semi-finished product 11 to the insert element 12 is through the arrows 15 represented symbolically. The semi-finished product lays down during the forming process 11 to the surface of the insert element facing him 12 and forms with the insert element 12 a composite component 10th which is in the middle representation B in 2nd is shown. As in the illustration B is clearly recognizable, also form in the in 2nd The method shown depends on the degree of deformation required on the semi-finished product for application to the surface 11 varying wall thicknesses 16 from, but complementary to the varying wall thicknesses 18th of the insert element 12 are. Accordingly, the varying wall thicknesses formed during the forming process are the same 16 of the semi-finished product 11 with the varying wall thicknesses 18th of the insert element 12 off, so that a composite component is formed 10th with essentially uniform wall thicknesses 19th trains.

In a further process step, the composite component designed in this way can 10th can be cut to a desired shape in the illustration C. is shown. There you can also see that the wall thickness 19th of the composite component produced using the exemplary method according to the invention 10th essentially homogeneous and independent of the degree of deformation of the semi-finished product 11 is trained. So the wall thickness corresponds 19th in the center of the composite component 10th the wall thickness 19th on the edges of the composite component 10th , because the wall thickness of the Insert element 12 in the center of the composite component 10th is correspondingly less than at the edges.

Reference symbol list

10th

Composite component

11

Workpiece

12

Insert element

13

uniform wall thickness of the semi-finished product

14

uniform wall thickness of the insert element

15

Movement of the semi-finished product

16

varying wall thicknesses of the semi-finished product

17th

varying wall thicknesses of the composite component

18th

varying wall thicknesses of the insert element

19th

uniform wall thickness of the composite component

20th

heater

22

molded elements

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• WO 02/072325 A1 [0002]

Claims (8)

Method for producing a thermoformed composite component from a thermoformable semi-finished product (11) and at least one insert element (12) with the following steps: - providing the thermoformable semi-finished product (11); - Providing the at least one insert element (12); - Heating the semi-finished product (11) to a forming temperature; - Forming the semifinished product (11) by applying negative pressure and / or excess pressure to the heated semifinished product (11), the semifinished product (11) applying to the surface of the insert element (12) facing it and depending on the particular application Forms the required degree of deformation of varying wall thicknesses (16); characterized in that for producing a thermoformed composite component (10) with essentially uniform wall thicknesses (19), the insert element (12) has varying wall thicknesses (18) which substantially compensate for the varying wall thicknesses (16) of the semifinished product formed during forming, so that a composite component (10) with substantially uniform wall thicknesses (19) is formed during the shaping. Method for manufacturing a thermoformed composite component according to Claim 1 , characterized in that the varying wall thicknesses (16) of the formed semifinished product (11) that are formed when applied to the surface of the insert element (12) are determined by a simulation method and the wall thicknesses (18) of the insert element (12) depend on the results of the Forming simulation can be defined. Method for producing a thermoformed composite component according to at least one of the preceding claims, characterized in that the insert element (12) is produced using an additive manufacturing process or an original molding process. Method for producing a thermoformed composite component according to at least one of the preceding claims, characterized in that the insert element (12) has at least air-permeable areas. Method for producing a thermoformed composite component according to at least one of the preceding claims, characterized in that the surface of the insert element (12) facing the semifinished product (11) is structured. Method for producing a thermoformed composite component according to at least one of the preceding claims, characterized in that when the at least one insert element (12) is provided, a mediator layer is applied to the surface of the insert element (12) facing the semifinished product (11). Method for producing a thermoformed composite component according to at least one of the preceding claims, characterized in that the insert element (12) has undercuts which form a positive connection with the semifinished product (11) through the reshaping of the semifinished product (11). Composite component, produced from a thermoformable semi-finished product (11) and at least one insert element (12), in particular with a method according to at least one of the preceding claims, characterized in that the at least one insert element (12) has varying wall thicknesses (18) which the through substantially compensate for thermoforming of wall thicknesses (16) of the semifinished product (11) in the region of the at least one insert element (12), so that the composite component (10) has a substantially uniform wall thickness (19).

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