DE102012002559A1 - Tool for use in method for manufacturing two covering elements and core element with sandwich composite component, has two tool elements, where former tool element has tool section and another tool section - Google Patents

Abstract

The tool (10) has two tool elements, where the former tool element has a tool section and another tool section that is moved along the direction relative to the former tool section. The latter tool section is arranged in a support system area corresponding to the covering elements (18,20) that are provided for pressing. The latter tool section, on pressing, is moved away from the latter tool element relative to the former tool section and to the latter tool element. The latter tool section is movably supported by a supporting element, particularly spring element (36).

Description

The invention relates to a tool for producing a sandwich composite component according to the preamble of patent claim 1 and to a method for producing a sandwich composite component according to the preamble of patent claim 6.

Such a tool and such a method are from the EP 0 894 611 B1 and from the DE 10 2010 005 456 A1 known. The sandwich composite component to be produced comprises at least two cover visible elements and at least one core element arranged between the cover layer elements. The tool for producing the sandwich composite component comprises two tool elements arranged opposite one another, between which the cover layer elements and the core element arranged between the cover layer elements are at least partially arranged during the production of the sandwich composite component. The cover elements and the core element are pressed by the tool elements are moved toward each other along a direction and are in at least partially in support system with the cover layer elements.

By pressing, the cover layer elements and the core element are joined together and the cover layer elements are consolidated. The consolidation is defined by means of the tool path controlled. This means that the tool elements moved towards each other to a predetermined distance, d. H. getting closed. This distance between the tool elements is always constant in the production of a plurality of sandwich composite components by means of the tool. This means that the tool elements in their closed state always have the same distance in the direction in which they are moved towards each other, from each other.

It is an object of the present invention to provide a tool and a method for producing a sandwich composite component, which enable the realization of particularly good mechanical properties of the sandwich composite component.

This object is achieved by a tool for producing a sandwich composite component having the features of patent claim 1 and by a method for producing a sandwich composite component having the features of patent claim 6. Advantageous embodiments with expedient and non-trivial developments of the invention are specified in the remaining claims.

In order to realize particularly advantageous mechanical properties of the sandwich composite component, according to the invention at least one first of the tool elements of the tool comprises at least a first tool part and at least one second tool part. The second tool part is movable relative to the first tool part along the direction. The second tool part is at least for pressing the cover layer elements and the core element arranged therebetween in at least partially support system with a corresponding one of the cover layer arranged and movable during pressing relative to the first tool part and relative to the second tool element from the second tool element along the direction away.

The tool according to the invention represents a force-controlled tool concept, by means of which, in contrast to the above-described, path-controlled closing of the tool elements, a force-controlled closing and thus pressing takes place. As a result, the consolidation of the cover layer elements during pressing does not take place over the always constant distance of the mutually moved and closed tool elements from each other, but by a force acting on the cover layer elements and the core element, which form a sandwich composite, from the second tool part force or on the sandwich composite of second tool part acting pressure.

A resulting surface load acting on the sandwich composite causes an increase in the mechanical properties of the sandwich composite component compared with the force-controlled production due to increased consolidation of the cover layer elements. Furthermore, variations in thickness of the core element and the cover layer elements are compensated by a force- or pressure-controlled adjustment of the height of the sandwich composite component between the tool elements.

If the core element is oversized, wrinkling or collapse of the core element can thereby be prevented.

The second tool part is supported, for example via at least one support element, in particular a spring element, movably on the first tool part relative to the first tool part along the direction. Preferably, during pressing, the second tool part is movable relative to the first tool part and relative to the second tool element along the direction away from the second tool element, until an equilibrium of forces, in particular independently, arises on the second tool part solely as a result of the pressing, wherein the equilibrium of forces is at least one of the corresponding one Covering layer element on the second tool part along the direction of the second Tool element away acting, first force and one of the support member on the second tool part along the direction of the second tool element to be acted upon and predetermined by the support member, second force. In other words, the second force acting on the second tool part, and thus the pressure exerted by the second tool part on the corresponding cover layer element during pressing, can be adjusted by a corresponding design of the support element. As a result, it is possible to realize particularly advantageous mechanical properties of the sandwich composite component as a result of advantageous consolidation of the cover layer elements.

The support element is preferably a spring element, via which the second tool part is movably supported on the first tool part so as to be movable relative to the first tool part. The force acting on the second tool part by the spring element during pressing force can thus be configured as required, for example, by adjusting or selecting the spring strength or the spring constant of the spring element.

Due to the movability of the second tool part relative to the first tool part of the first tool element and relative to the second tool element away from the second tool element and as a result of the force-controlled production of the sandwich composite component realized thereby, the distance between the moving towards each other for pressing, d. H. closed tool elements in a plurality of manufacturing operations vary. This variation of the spacing results, for example, in particular manufacturing tolerances of the cover layer elements and / or the core element, in particular with regard to their height between the tool elements.

Due to the mobility of the first tool part relative to the second tool part and in particular relative to the second tool element, the cover layer elements can be advantageously consolidated even with the described tolerances in a very high quality and a very high reproducibility, which also at the occurrence of tolerances to very good mechanical properties by means of the tool according to the invention produced sandwich composite components. In particular, creasing and / or otherwise compressing or folding the core element with varying thickness or height of the core element and thus of the sandwich composite as a result of the support system of the second tool part on the sandwich composite can be avoided.

The cover layer elements may be textile cover layer elements which comprise, for example, a fleece, a woven fabric or other text elements. In particular, the cover layer elements may be at least substantially formed of a fiber-reinforced plastic, wherein the plastic is, for example, a thermosetting plastic and acts as a matrix in which fibers are accommodated. The plastic is for example polypropylene. The fibers are formed, for example, as glass fibers.

The core element has, for example, a honeycomb structure. The core element can be made of paper, at least substantially of aluminum, of Kevlar or of another material.

In the method according to the invention, the second tool part is arranged at least for pressing in the at least partially support system with the corresponding cover layer element and as a result of a force acting on the second tool part by the corresponding cover layer element during pressing force relative to the first tool part and relative to the second tool element along the direction of the second Tool element moved away. Advantageous embodiments of the tool according to the invention are to be regarded as advantageous embodiments of the method according to the invention and vice versa.

The second tool part is thereby moved away only as a result of the force from the second tool element, wherein the force is a reaction force due to the pressing. In other words, the second tool part is not moved away from the second tool element by means of an active actuator, but moves virtually autonomously in response to the pressing of the corresponding cover layer over the second tool part.

In the method according to the invention, the consolidation of the cover layer elements is force-controlled and not, as conventionally provided, path-controlled. This results in particularly advantageous mechanical properties of the sandwich composite component due to improved consolidation of the cover layer elements, in particular in comparison to the path-controlled production of the sandwich composite component. In addition, wrinkling and / or otherwise upsetting of the core element by thickness compensation of the sandwich composite component can be prevented.

Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing. The features and feature combinations mentioned above in the description as well as the features mentioned below in the description of the figures and / or in the figures alone, and Feature combinations can be used not only in the specified combination, but also in other combinations or in isolation, without departing from the scope of the invention.

The drawing shows in:

1 a schematic sectional view of a tool for force-controlled production of a sandwich composite component; and

2 a schematic and partially sectioned plan view of a composite sandwich component, which force controlled and, for example by means of the tool according to 1 is made.

1 shows a tool 10 for producing a sandwich composite component 12 , The tool 10 comprises a first tool element, which serves as a first tool half 14 referred to as. Furthermore, the tool includes 10 a second tool element, which serves as a second tool half 16 referred to as.

The sandwich composite component 12 comprises a first cover layer element 18 and a second cover layer element 20 which are arranged opposite to each other and between which a core element 22 of the sandwich composite component 12 is arranged. The cover layer elements 18 . 20 and the core element 22 form a sandwich composite, which leads to a very high rigidity of the sandwich composite component 12 and for the realization of only a very small weight of the sandwich composite component 12 leads.

For producing the sandwich composite component 12 become the opposing tool halves 14 . 16 moved away from each other, ie open. Subsequently, the cover layer elements 18 . 20 and the interposed core element 22 into a tool cavity 24 the second tool half 16 inserted. The tool cavity 24 is by a die 26 the second tool half 16 formed, with the die 26 with a foot plate 28 the second tool half 16 is firmly connected.

The first tool half 14 includes a top plate 30 and a fixed or rigid with the top plate 30 connected stamping frame 32 , In addition, includes the first tool half 14 a stamp 34 , which has a spring elements 36 comprehensive spring system 38 on the top plate 30 relative to the top plate 30 and relative to the stamp frame 32 is movably supported and on the stamp frame 32 rests. In addition, guide bolts 40 the first tool half 14 provided, which is a vertical guide of the punch 34 relative to the top plate 30 and relative to the stamp frame 32 allows.

After arranging the cover layer element 18 . 20 and the core element 22 between the tool halves 14 . 16 become the tool halves 14 . 16 along a direction relative to each other moves towards each other, ie closed by the first mold half 14 relative to the second tool half 16 is moved towards this. As a result, the cover layer elements 18 . 20 and the core element 22 pressed, wherein the cover layer elements 18 . 20 , Which present textile cover layer elements 18 . 20 are, consolidated and with the core element 22 , which in the present case has a paper honeycomb structure can be connected.

As a result of moving the tool halves towards each other 14 . 16 the stamp hits 34 to the corresponding, first cover layer element 18 on, ie the stamp 34 is in support system with the first cover layer element 18 emotional. When the stamp hits 34 is due to the preloaded spring system 38 a compressive force on the stamp 34 exerted on the sandwich composite and derived flat on the sandwich composite. If necessary, an edge closure of the composite sandwich component associated with the pressing of the sandwich composite 12 in edge regions of the cover layer elements 18 . 20 may be a progressive closing of the tool halves 14 . 16 in the area of the movable punch 34 by an increasing compression of the spring elements 36 cause a pressure force increase. In the area of the stamp frame 32 wrinkles the honeycomb structure of the core element 22 in edge regions of the sandwich composite component 12 perfectly together until a circumferential Pinchkante, with which the stamp frame 32 is provided by the high pressure pruned the blocked sandwich composite.

When designing the spring system 38 It should be noted that an effective stamping pressure p _ST does not exceed a compressive strength of the paper honeycomb structure. The compressive strength of the paper honeycomb structure is expressed _herein by σ _C33 , giving: p _ST ≤ σ _C33

Taking into account a projected area A _{pr of} the sandwich composite component 12 and the compressive strength of the paper honeycomb structure can be a maximum force F _{STmax of} the movable punch 34 determine the sandwich composite by the following equation: F _STmax ≤ A _pr σ _C33

The stamping force F _ST acting on the projected area A _pr is made up of the weight G _{ST of} the movable punch 34 and the sum of the individual, acting spring forces F _{F of} the spring elements 36 together. This results in: F _ST = G _ST + ΣF _F

Assuming a proportional behavior between spring force F _F and spring deflection .DELTA.L _F , the number of springs, the choice of the respective spring constant D _F and the required spring deflection can be calculated.

wobei η_D die mechanische Beanspruchung des Kernelements 22 ausdrückt. Hierbei entspricht ein Druckverhältnis von 1 der theoretisch maximalen Druckbeanspruchung des Kernelements 22, wobei eine Beanspruchung größer als 1 zu einem Versagen des Kernelements 22 führt.For the mechanical stress of the core element 22 For example, the quotient of acting stamping pressure and compressive strength of the paper honeycomb structure can be considered as an evaluation value of the stress of the paper honeycomb structure. It follows:

where η _{D is} the mechanical stress of the core element 22 expresses. Here, a pressure ratio of 1 corresponds to the theoretical maximum compressive stress of the core element 22 , wherein a stress greater than 1 to a failure of the core element 22 leads.

In the production of sandwich composite component 12 by means of the tool 10 according to 1 the closing process of the tool halves takes place 14 . 16 force controlled and not driven away. In the force-controlled closing process, in contrast to a path-controlled closing process, a consolidation of the textile cover layer elements 18 . 20 not by a constant distance between the tool halves across several manufacturing processes 14 . 16 , but defined by the pressure acting on the sandwich composite. This leads to the realization of particularly good mechanical properties of the sandwich composite component 12 and to avoid wrinkling of the core element 22 in the area of the movable punch 34 for example, by varying thicknesses of the tool 10 Sandwich composite components to be produced 12 ,

2 shows a sandwich composite component 12 , which by means of a force-controlled closing operation of the tool halves 14 . 16 and thus for example by means of the tool 10 according to 1 is made. In the sandwich composite component 12 according to 2 it is, for example, an interior trim part of a motor vehicle, in particular a passenger car. The core element 22 In the present case, it has a honeycomb structure with a specific haunch thickness. These are hexagonal honeycombs. The cover layer elements 18 . 20 are formed as hybrid needle nonwovens and formed at least substantially of polypropylene and glass fibers having a certain basis weight and a 40% fiber mass fraction and with a polypropylene film having a certain thickness to increase the outer layer bond. The sandwich composite component 12 is with a cyclic temperature control of the tool 10 and the force controlled tool closing operation. By a subsequent, manual lamination can be the honeycomb structure of the core element 22 on the cover layer elements 18 . 20 be laminated.

The force-controlled closing process of the tool halves 14 . 16 allows a very high cover layer connection, a very high degree of consolidation of the cover layer elements 18 . 20 as well as a compensation of material fluctuations. Furthermore, a tool-integrated component trim as well as a shift of cover layer joining surfaces from the vertex of the component contour is possible.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely 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.

Cited patent literature

• EP 0894611 B1 [0002]
• DE 102010005456 A1 [0002]

Claims (6)

Tool ( 10 ) for producing at least two cover layer elements ( 18 . 20 ) and at least one between the cover layer elements ( 18 . 20 ) core element ( 22 ) sandwich composite component ( 12 ), with two opposing tool elements ( 14 . 16 ), between which the cover layer elements ( 18 . 20 ) and the core element ( 22 ) are at least partially locatable and which for pressing the cover layer elements ( 18 . 20 ) and the core element ( 22 ) are movable towards each other, characterized in that at least a first of the tool elements ( 14 . 16 ) at least a first tool part ( 30 . 32 ) and at least one relative to the first tool part along the direction movable, second tool part ( 34 ), which at least for pressing in at least partially support system with a corresponding one of the cover layer elements ( 18 . 20 ) and when pressing relative to the first tool part ( 30 . 32 ) and relative to the second tool element ( 16 ) of the second tool element ( 16 ) is movable away. Tool ( 10 ) according to claim 1, characterized in that the second tool part ( 34 ) via at least one support element ( 36 ) on the first tool part ( 30 . 32 ) relative to the first tool part ( 30 . 32 ) is movably supported. Tool ( 10 ) according to claim 2, characterized in that the second tool part ( 34 ) during pressing relative to the first tool part ( 30 . 32 ) as long as the second tool element ( 16 ) is movable away until at the second tool part ( 34 ) adjusts a balance of forces, which at least one of the corresponding cover layer element ( 18 ) on the second tool part ( 34 ) of the second tool element ( 16 ) acting away, first force and one of the support element ( 36 ) on the second tool part ( 34 ) on the second tool element ( 16 ) and by means of the supporting element ( 36 ) predeterminable second force (F _F ). Tool ( 10 ) according to one of claims 2 or 3, characterized in that the supporting element ( 36 ) on the one hand on the first tool part ( 30 . 32 ) and on the other hand on the second tool part ( 34 ) at least indirectly supported spring element ( 36 ). Tool ( 10 ) according to claim 4, characterized in that the spring element ( 36 ) when moving the second tool part ( 34 ) relative to the first tool part ( 30 . 32 ) is to compress. Method for producing at least two cover layer elements ( 18 . 20 ) and at least one between the cover layer elements ( 18 . 20 ) core element ( 22 ) sandwich composite component ( 12 ) using a tool ( 10 ), in particular according to one of the preceding claims, with two tool elements ( 14 . 16 ), between which the cover layer elements ( 18 . 20 ) and the core element ( 22 ) are at least partially arranged and which for pressing the cover layer elements ( 18 . 20 ) and the core element ( 22 ) are moved towards each other, characterized in that at least a first of the tool elements ( 14 . 16 ) at least a first tool part ( 30 . 32 ) and at least one second tool part ( 34 ), which at least for pressing in at least partially support system with a corresponding of the cover layer element ( 18 ) and due to a pressing of the corresponding cover layer element ( 18 ) on the second tool part ( 34 ) acting force relative to the first tool part ( 30 . 32 ) and relative to the second tool element ( 16 ) of the second tool element ( 16 ) is moved away.

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