Method for manufacturing a lightweight component, in particular a body part

Abstract

Method for manufacturing a lightweight component (22) formed from a metal sheet (16), a fiber fabric or fiber lay-up embedded in a thermoplastic polymer matrix (21) and a mass of fiber-reinforced plastic (20), in particular for manufacturing a body part, wherein - a forming tool (1) having a forming upper part (2) and a forming lower part (3) is moved into an open position, - the metal sheet (16) is inserted from below into the tempered upper part of the mold (2) and fixed, - the molding tool (1) is moved into a closed position, during compression of the fiber fabric or fiber layup embedded in the thermoplastic polymer matrix (21) and formation of a structure (23) from the fiber-reinforced polymer (20) arranged between the fiber fabric or fiber layup embedded in the thermoplastic polymer matrix (21) and the mold base (3), characterized in that - the lower part of the mold (3) has upwardly directed projections (4), wherein the fiber-reinforced plastic (20), which is heated, is inserted into a recess (9) formed between the projections (4), - the fiber fabric or fiber lay-up embedded in the thermoplastic polymer matrix (21) is heated and laid down and draped onto the projections (4).

Description

[0001] The invention relates to a method for manufacturing a lightweight component formed from a metal sheet, a fiber fabric or a fiber layup embedded in a thermoplastic polymer matrix, and a fiber-reinforced plastic, in particular for manufacturing a body part, wherein a molding tool having an upper mold part and a lower mold part is moved into an open position, the metal sheet is inserted from below into the tempered upper mold part and fixed, the molding tool is moved into a closed position, the fiber fabric or fiber layup embedded in the thermoplastic polymer matrix is ​​compressed, and a structure is formed from the fiber-reinforced plastic arranged between the fiber fabric or fiber layup embedded in the thermoplastic polymer matrix and the lower mold part.In particular, the invention relates to a method for manufacturing a body part, which is designed in particular as a longitudinal or transverse beam or a vertically extending column.

[0002] A fibrous fabric or woven material embedded in a thermoplastic polymer matrix is ​​also known as an organosheet.

[0003] One such method is known, for example, from DE 10 2009 042 272 A1. To manufacture the lightweight component, the following steps are first taken: A metal sheet is inserted from above into a lower mold part. The heated organosheet is then applied to the metal sheet. Extruded fiber-reinforced plastic is then layered onto the heated organosheet. Finally, the upper mold part is placed on top, and the two mold parts are pressed together, thus closing the mold. The result is a lightweight component, particularly a body panel, made of a metal sheet with a plastic reinforcement structure. The metal sheet is bonded to the plastic reinforcement layer, i.e., the organosheet. This reinforcement layer is, in turn, bonded to the plastic reinforcement structure. Examples of generic processes are described in DE 20 2007 007 498 U1 and DE 10 2010 037 022 A1.Furthermore, it is known from DE 38 90 321 T5 and US 5 618 567 A to provide protrusions between which a heated, fiber-reinforced plastic is arranged.

[0004] The object of the present invention is to provide an improved method for manufacturing a lightweight component consisting of a metal sheet, a woven or non-woven fabric embedded in a thermoplastic matrix, and a fiber-reinforced plastic. The method should enable the lightweight component to be manufactured in a single pressing operation, thereby avoiding process disadvantages, particularly the critical temperature-time management, and improving the positioning accuracy of the components.

[0005] The problem is solved by a method that has the features of claim 1.

[0006] The inventive method uses a mold comprising an upper and a lower mold part. This mold is first moved into an open position. A metal sheet is then inserted from below into the heated upper mold part and secured. This securing can be achieved in various ways, for example, by magnets or mechanical clamps. The lower mold part has upward-facing projections. Heated fiber-reinforced plastic is placed in a recess between these projections. The heated organosheet, a woven or woven fiber fabric embedded in the thermoplastic matrix, is then laid and draped onto the projections.In particular, the heated, laid-down organosheet is draped in one direction and then shaped in a second direction by elements not shown, which drape areas of the organosheet extending beyond the projections into the desired shape. The mold is then moved into the closed position. This involves compressing the fiber fabric or fiber layup embedded in the thermoplastic matrix and forming a structure from the fiber-reinforced plastic located between the fiber fabric or fiber layup embedded in the thermoplastic matrix and the mold base.When the mold closes, the flow of fiber-reinforced plastic presses the organosheet into the corresponding contour of the metal sheet, forming the structure of the lightweight component from the fiber-reinforced plastic according to the geometry of the mold base. The fiber-reinforced plastic is, in particular, a glass-reinforced plastic. The structure serves primarily to reinforce the lightweight component.

[0007] Thus, it is possible to produce the lightweight component in a single pressing process, with the one-time closing of the mold.

[0008] Preferably, the lightweight component is manufactured through the interaction of the metal sheet with an associated transmitter layer. The transmitter layer is preferably assigned to the side of the metal sheet, which is fixed in the upper mold part, facing the lower mold part. This layer can be arranged in various ways or integrated into the manufacturing process. For example, the metal sheet can be coated with the transmitter layer before being inserted into the upper mold part. According to another preferred alternative, the transmitter layer is inserted into the metal sheet as a preform. In yet another preferred alternative, the transmitter layer is arranged as a stretched film between the metal sheet and the fiber fabric or fiber layup embedded in the thermoplastic polymer matrix.

[0009] The method is preferably used with a mold that has a top mold part designed as a die and a bottom mold part designed as a male die. The top mold part is thus negatively shaped, while the bottom mold part is positively shaped.

[0010] The projections used in the mold base serve primarily to hold the heated fiber-reinforced plastic between them and to lay the heated fiber fabric or fiber layup, embedded in the thermoplastic matrix—thus forming the organosheet—on the projections, draping it in place. These projections, especially thin and therefore delicate ones, prevent close contact with the relatively cold mold and thus prevent premature cooling of the heated and inserted materials before the actual pressing process. For the subsequent pressing process to produce the lightweight component, it is essential to ensure that both the organosheet and the fiber-reinforced plastic have reached a sufficiently high temperature.This ensures that the thermoplastic materials bond intimately, or that the fiber-reinforced plastic has sufficient flowability to fill the structure (e.g., ribs), and that the transmitter layer is exposed to a sufficient temperature to melt, react, harden, and develop its necessary properties. The transmitter layer has a considerable thickness, preferably in the range of 0.1 mm to 0.3 mm. It is therefore significantly thicker than an adhesion promoter (primer) and serves a different function. Maintaining tool integrity and ensuring high quality of the lightweight components are further linked to adhering to a time- and temperature-critical process during the feeding of these components. The locally required amount of fiber-reinforced plastic depends on the local volume requirement in the mold for forming the structure. The organosheet, on the other hand, must be draped spatially before the pressing process.In principle, draping is possible through the gravity of the organosheet and the subsequent closing process of the molding tool.

[0011] The upward-facing projections can be designed in various ways to accommodate and drape the heated organosheet. Preferably, the upward-facing projections are formed directly by the mold base. This results in a simple and stable construction of the mold in the area of ​​the mold base. Contact surfaces between the cold mold base and the heated fiber-reinforced plastic, as well as the heated organosheet, are thus minimized.

[0012] According to a particularly advantageous embodiment, during the production of the lightweight component, a sealing frame movable along the lower mold section contacts the underside of the metal sheet in the area of ​​its circumferential edge before the mold is closed, sealing it against an interior area of ​​the metal sheet. This sealing frame also holds the previously draped organosheet in its shape. This ensures that neither thermoplastic material nor organosheet can be present in the area of ​​the metal sheet's circumferential edge during the manufacturing process. This exclusively metallic edge area of ​​the lightweight component allows for straightforward connection of the lightweight component to adjacent components, in particular, contact between this metallic area of ​​the lightweight component and neighboring metallic components during the subsequent vehicle production process.When the tool is closed, the sealing frame moves into the lower part of the tool, reducing the space in which the organosheet and the fiber-reinforced plastic are located, and with the increasing pressure, the plastic is pressed into the cavity and can build up the reinforcing plastic structure.

[0013] Further features of the invention will become apparent from the dependent claims, the accompanying drawing and the description of the preferred embodiment of the method according to the invention shown in the drawing, without being limited thereto.

[0014] It shows: Fig. 1 a forming tool according to a first embodiment, for carrying out a non-inventive method, illustrated in a sectional view of the forming tool, Fig. 2 to Fig. 8 process sequences with the forming tool according to Fig. 1 for the manufacture of a lightweight component, in particular a body part, Fig. 9 a non-inventive variant regarding Fig. 2, concerning the arrangement of metal sheet and transmitter layer, Fig. 10 a forming tool according to a second embodiment according to the invention, for carrying out the method according to the invention, illustrated in a sectional view of the forming tool, Fig. 11 to Fig. 15 process sequences with the forming tool according to Fig. 10 for the production of a lightweight component, made of sheet metal, fiber-reinforced plastic and organosheet. Character description

[0015] Fig. Figure 1 shows a mold 1 for manufacturing a lightweight component, in particular a body panel of a motor vehicle. This body panel is, for example, a B-pillar of a passenger car. The mold 1 is shown in a sectional view, cut transversely to the longitudinal extent of the B-pillar. Consequently, the mold extends over a relatively large length perpendicular to the plane of the drawing. Fig. 1.

[0016] The mold 1 has a mold upper part 2 and a mold lower part 3. The mold 1 is in Fig. 1 shown in fully open position. The upper mold part 2 is designed as a die, the lower mold part 3 as a male die.

[0017] The lower mold part 3 has upwardly directed projections 4. In the exemplary embodiment according to Fig. 1. The projections 4 are not formed directly by the mold base 3, but are mounted in a punch 5 of the mold base 3. Specifically, the upwardly directed projections 4 are mounted in the punch 5 so as to be retractable and extendable. In the initial state according to Fig. 1. The projections 4 are fully retracted into the punch 5. The projections 4 are supported in a common bearing plate 6, so that the projections 4 are extended and retracted synchronously when the bearing plate 6 is actuated.

[0018] The upper part of the mold 2 has a recess 7, and the punch 5 has a raised section 8 that is complementary to the recess 7. The difference in geometry forms the cavity in which the lightweight component to be manufactured is arranged. In the area of ​​the raised section 8, the punch 5 is provided with recesses 9 for the rib and reinforcement geometry. Corresponding to the recesses 9, the projections 4 extend through the bores 10 in the punch 5.

[0019] Due to the longitudinal extent of the forming tool 1, and thus its extension perpendicular to the plane of the die, a multitude of projections 4 penetrate corresponding bores 10 in the punch 5, which are connected to the common bearing plate 6. Thus, a channel 11 extending perpendicular to the plane of the die is formed between the arrangement of projections 4 (see figure). Fig. 2) formed when the projections 4 are in their extended position.

[0020] On both sides of the raised section 8 of the punch 5, recessed areas 12, in particular grooves extending perpendicular to the plane of the die, are provided in the punch 5 on the side facing the upper part 2. These grooves accommodate a sealing frame 13, which can be extended and retracted. The sealing frame 13 is supported on its side facing away from the upper part 2 in rods 14, which in turn are supported in a common bearing plate 15. This bearing plate 15 can be actuated via the actuating means, so that the sealing frame 13 extends from the Fig. Figure 1 illustrates the retracted position in which the sealing frame 13 is inserted into the punch 5 and can be partially extended from the punch 5. The sealing frame 13 is arranged such that, in its extended position, it can seal in the area next to the recess 7 of the upper mold part 2. Through openings in the lightweight component require openings in the metal sheet 16, which are closed by spring-loaded sealing plungers that are in turn linked to the movement of the sealing frame 13.

[0021] The method for manufacturing the lightweight component using the mold 1 according to the embodiment shown in Fig. 1. As can be seen from the presentation of the Fig. 2 to Fig. Figure 8 illustrates as follows: How to Fig. As shown in Figure 2, a metal sheet 16 is inserted from below into the recess of the tempered mold upper part 2 and fixed in place. Openings in the metal sheet 16 are preferably closed by thin sheets or plugs. Open openings are possible for creating undercuts or for realizing through openings in the lightweight component to be manufactured. The metal sheet 16 is fixed, for example, magnetically or by claws provided in the mold upper part 2. The recess 7 is shaped according to the three-dimensional shape of the metal sheet 16 and has flange sections 18 adjacent to the section 17 associated with the recess 7. On the side facing the mold lower part 3, the metal sheet 16 is coated with a transmitter layer 19. The coating of the metal sheet 16 is carried out, for example, by powder coating.

[0022] During the procedural section according to Fig. 2. The projections 4 are extended and the sealing frame 13 remains in its position retracted into the piston 5.

[0023] Subsequently, as per the procedural section according to Fig. Figure 3 illustrates that a mass 20 made of fiber-reinforced, in particular glass fiber-reinforced, plastic is introduced between the projections 4 and is heated. This mass 20 is designed as a strand that is positioned in the direction of extension perpendicular to the plane of the sheet over the length of the mold 1 between the projections 4 and is thereby placed on the punch 5 in the area of ​​the recess 9.

[0024] Then, according to the [relevant], the following will be done Fig. In the process section 4 shown, a fibrous fabric or a fibrous lay-up embedded in a thermoplastic polymer matrix, hereinafter referred to as organosheet 21, is heated and deposited onto the upper, free ends of the projections 4.

[0025] For example, regarding the in the Fig. 3 and Fig. In the process steps shown in Figure 4, the mass 20 of fiber-reinforced plastic is deposited portion by portion along the length of the mold 1 between the projections 4 or deposited there directly via a robot-guided extruder nozzle. The depositing of the organosheet 21 onto the projections 4 is preferably carried out by means of a robot.

[0026] Then, as the Fig. As can be seen from Figure 5, the hot and therefore deformable organosheet 21 is spatially draped. In this process, the organosheet 21 is first deformed in the direction perpendicular to the sheet plane and then downwards in its outer area extending beyond the projections 4, into the area between the projections 4 and the sealing frame 13.

[0027] Then, as if to Fig. Figure 6 illustrates the sealing frame 13 extended and overall, as for Fig. As shown in Figure 7, the punch 5, together with the sealing frame 13, is moved towards the upper part of the mold 2. This position ensures that the organosheet 21, draped in two directions by a device not shown, is held in its shape.

[0028] The further movement beyond the state illustrates Fig. 7, in which the sealing frame 13 contacts the flange sections 18 of the metal sheet 16 at its end face and thus seals in the direction of the recess 7 of the upper part of the mold 2. During the subsequent rapid closing of the mold tool 1 Fig. 7 to Fig. 8 The actual pressing process for forming the lightweight component 22 takes place, in which both the sealing frame 13 and the projections 4 are inserted, thus enabling the pressing of metal sheet 16 with transmitter layer 19, organosheet 21 and mass 20 made of fiber-reinforced plastic to form a rib structure of the lightweight component 22 defined by the shape of the punch 5. A rib produced in this way is designated by the reference numeral 23.

[0029] Due to the sealing function of the sealing frame 13, it is possible to create lightweight components in which the pressed plastic structure is interrupted, or the metal sheet 16 remains free of plastic, or in which a sheet opening is required. This is achieved by placing the spring-loaded sealing frame 13 onto the area of ​​the metal sheet 16 that is to be kept free of plastic before the pressing process.

[0030] After the pressing process Fig. 8. The opening of the forming tool 1 follows, into the position according to Fig. 1, in which the produced lightweight component 22 is removed from the mold 1. In the first phase of demolding, both the sealing frame 13 and the projections 4 are moved synchronously with the opening movement of the upper part 2. After the lightweight component separates from the punch 5, the sealing frame remains in position relative to the lower part, and only the projections 4 push the lightweight component into the position for final removal.

[0031] Fig. Figure 9 shows, with regard to the procedural section according to Fig. 2, a modification. Here, a metal sheet 16 without a coated transmitter layer 19 is inserted from below into the temperature-controlled upper mold part 2 and fixed in place. Subsequently, the transmitter layer 19 is arranged as a stretched film between the upper mold part 2 and the lower mold part 3 below the metal sheet 16. The process section according to Fig. 9 the procedural stages according to the Fig. 3 to Fig. 8, wherein when closing the forming tool 1, as described above Fig. 7 and Fig. Figure 8 shows that the transmitter layer 9 is deformed and placed against the metal sheet 16. In principle, therefore, under the described procedures, the transmitter layer 19 ensures sufficient adhesion between the metal sheet 16 and the organosheet 21, taking into account the elevated temperature over time.

[0032] While in the non-inventive embodiment according to the Fig. 1 to Fig. Figure 9 shows that the stamp 5 is a single piece, as shown in the embodiment according to the invention. Fig. 10 and the process steps relating to this embodiment according to the Fig. 11 to Fig. 15 a multi-part stamp 5 of the mold base 3. With the embodiment according to the Fig. For simplicity, identical components are designated with the same reference numbers.

[0033] In the case of the forming tool 1 according to Fig. In section 10, the lower mold part 3 has a punch 5, which has a central punch part 24 and an outer punch part 25 arranged outside this punch part 24. The outer punch part 25 has the projections 4. The two punch parts 24 and 25 can be moved independently of each other, thus extending towards the upper mold part 2 and retracting in the opposite direction.

[0034] In Fig. Figure 10 already illustrates the metal sheet 16 inserted into the upper part of the mold 2. This is held in the upper part of the mold 2, for example, magnetically. Subsequently, as shown in the illustration in Fig. As can be seen from Figure 11, the mass 20, made of fiber-reinforced plastic, in particular glass fiber-reinforced plastic, is inserted into the recess 9 formed between the projections 4, which is located above the central punch part 24. The mass 20 is thus placed on the central punch part 24. This mass 20 is applied in a heated state, as described in the first embodiment. Subsequently, the heated organosheet 21 is, as described in the first embodiment... Fig. Figure 12 illustrates how to place the items on the projections 4 and drape them there. Then, according to... Fig. 13, the sealing frame 13, which accommodates the punch 5 between it, is extended and pressed against the metal sheet 16 coated with the transmitter layer 19. At those points where the sealing frame 13 contacts the metal sheet 16 with the transmitter layer 19, no connection is subsequently made between the organosheet 21 and the metal sheet 16. Subsequently, as shown in the illustration of the Fig. As can be seen from Figure 14, the outer punch part 25 is extended, thus moving into the pressing position against the upper mold part 2, so that the organosheet 21 is deformed according to the contour of the metal sheet 16. Finally, the central punch part 24 is extended, whereby the fiber-reinforced plastic mass 20 is compressed and the lightweight component 22 is produced. Due to the illustrated design of the central punch part 24, a portion of the fiber-reinforced plastic mass 20 is displaced into a space between the central punch part 24 and the outer punch part 25, thereby creating the rib 23 of the lightweight component 22 by means of a portion of the mass 20. After completion of the process described in Figure 14, the organosheet 21 is deformed. Fig. In the illustrated pressing process (15), the mold 1 is opened again, thus moving the lower mold part 3 away from the upper mold part 2. The resulting lightweight component 23 can then be removed from the mold 1. Reference symbol list 1 forming tool 2 Form top 3 Mold base 4 lead 5 stamps 6 bearing plate 7. Further Study 8 increase 9 Exclusion 10 Drilling Channel 11 12 Recessed area / groove 13 sealing frames 14 bars 15 bearing plate 16 sheet metal Section 17 18 Flange section 19 Transmitter layer 20 Mass made of fiber-reinforced plastic 21 Organosheet 22 Lightweight component 23rd rib 24 Central stamp part 25 Outer stamp part

Claims

[1] Method for producing a lightweight component (22) formed from a metal sheet (16), a fiber fabric or fiber lay-up embedded in a thermoplastic polymer matrix (21) and a mass of fiber-reinforced plastic (20), in particular for producing a body part, wherein - a forming tool (1) having a forming upper part (2) and a forming lower part (3) is moved into an open position, - the metal sheet (16) is inserted from below into the tempered upper part of the mold (2) and fixed, - the mold tool (1) is moved into a closed position, during compression of the fiber fabric or fiber layup embedded in the thermoplastic polymer matrix (21) and formation of a structure (23) from the fiber-reinforced polymer (20) arranged between the fiber fabric or fiber layup embedded in the thermoplastic polymer matrix (21) and the mold base (3),characterized by , that - the lower part of the mold (3) has upwardly directed projections (4), wherein the fiber-reinforced plastic (20), which is heated, is inserted into a recess (9) formed between the projections (4), - the fiber fabric or fiber lay-up embedded in the thermoplastic polymer matrix (21) is heated and laid down and draped onto the projections (4). [2] Method according to claim 1, wherein a transmitter layer (19) is assigned to the metal sheet (16) fixed in the upper part of the mold (2) on the side of which facing the lower part of the mold (3). [3] Method according to claim 2, wherein the transmitter layer (19) has a thickness of at least 0.1 mm, in particular a thickness of 0.1 to 0.3 mm. [4] Method according to claim 2 or 3, wherein the metal sheet (16) is coated with the transmitter layer (19) before being inserted into the mold top part (2). [5] Method according to claim 2 or 3, wherein the transmitter layer (19) is inserted as a preform into the metal sheet (16). [6] Method according to claim 2 or 3, wherein the transmitter layer (19) is arranged as a stretched film between the metal sheet (16) and the fiber fabric or fiber lay-up embedded in the thermoplastic polymer matrix (21). [7] Method according to any one of claims 1 to 6, wherein the upper part of the mold (2) forms a die and the lower part of the mold (3) forms a male die. [8] Method according to any one of claims 1 to 7, wherein the upward-facing projections (4) are formed directly by the mold base (3). [9] Method according to any one of claims 1 to 8, wherein a sealing frame (13) movable in the lower part of the mold (3) contacts the metal sheet (16) on its underside in the area of ​​a circumferential edge (18) and seals it to an inner area of ​​the metal sheet (16) before the mold tool (1) is closed. [10] Method according to claim 9, wherein the sealing frame (13) in the lower part of the mold (3) is extended to such an extent that the draped fiber fabric or fiber lay-up embedded in the thermoplastic polymer matrix is ​​held and, with the subsequent closing of the mold tool (1), a press chamber is formed by sealing the sealing frame (13) to the press chamber with contact to the metal sheet (16) or the transmitter layer (19). [11] Method according to claim 9 or 10, wherein a spring-loaded sealing plunger coupled to the movement of the movable sealing frame (13) is arranged such that open areas in the metal sheet (16) are closed by sealing.

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