Forming- and expansion-tool

Abstract

The present invention relates to a forming- and expansion-tool with a first- and a second mould and space between the first- and the second mould to accommodate a sheet to be formed and expanded. The present invention also relates to a method to form and expand a sheet.

Description

[0001] Forming- and Expansion-Tool

[0002] The present invention relates to a forming- and expansion-tool with a first- and a second mould and space between the first- and the second mould to accommodate a sheet to be formed and expanded. The present invention also relates to a method to form and expand a sheet.

[0003] In automotive application large parts are need for acoustic dampening, for example between the motor and the driver cabin or as the floor of the driver cabin. Those parts are 3D-formed and comprise an expandable layer, which is expanded in a forming- and expansion tool. Those tools are large and hence difficult to handle and / or to produce and the process to form and expand the sheet is difficult to control.

[0004] There is therefore a constant need to improve such tolls and / or the method to form and expand the sheet.

[0005] The problem is attained by a forming- and expansion-tool with a first- and a second mould and space between the first- and the second mould to accommodate a sheet to be formed and expanded, wherein the first- and / or the second-mould is provided by multiple segments.

[0006] The disclosure made regarding this subject matter also applies to the other subject matters and vice versa. Subject matters disclosed in the context of one subject matter can be incorporated into other subject matters.

[0007] This subject matter of the present invention relates to a tool to form and expand a sheet.

[0008] The sheets are preferably used in automotive applications, particularly in truck applications. The sheet can, for example, be utilized as the floor of a cabin. The sheets have preferably a large extension, for example more than half a square meter, more preferably > 0,7 square meter. The sheets are conventionally 3D-formed. Preferably, the sheet is a sandwich of two metal layers, preferably at least one aluminum layer, as the two opposing surface layers of the sheet and an expandable polymeric material in between. At least one surface layer is preferably embossed, for example with an anti-slip structure. The pressure resulting from the expansion of the polymeric material, at least assists in shaping the sheet into its final form. This embossing is preferably maintained during forming and expansion of the sheet.

[0009] The expansion of the expandable polymeric material is preferably carried out under the influence of heat, for example by activating a blowing agent. The expansion of the sheet, increases the distance between the two opposing surface layers. After expansion, the polymeric material preferably cures and maintains the sheet in its expanded final form and provides stiffness. The sheet is preferably utilized to reduce noise and as a heat insulation.

[0010] According to the invention, the forming- and expansion-tool comprises a first- and a second mould, preferably two opposing moulds, for example an upper and a lower mould which cooperate in providing the desired form for the sheet. Preferably, the two mould can be moved relative to each other from a remote- to a forming position. The mould is preferably made from metal, more preferably aluminum. Preferably at least one of the moulds, more preferably both mould can be heated.

[0011] Inventively, the first- and / or the second-mould is provided by multiple segments. Each segment preferably extends over one or two entire dimensions, for example the height and width of the mould. The third dimension, for example the length is divided into multiple segments. The thickness of a segment can be selected individually. Potential selection criteria is the precision of the temperature control of the forming surface and / or the weight of segment and / or the wear of a segment. The segments are preferably put side by side in the third direction. Each segment preferably provides a part of the forming surface that is in touch with the sheet to be formed and expanded. The segment is preferably hollowed out in regions opposite of the forming surface where mechanical stiffness is not needed. This reduces the thermal inertia of the segment.

[0012] Preferably, the segments are connected to a frame. The frame is preferably provided on the opposite side of the forming surface of the segments. The frame is preferably rectangular or square. The frame may comprises cross-members which preferably span from one side of the frame to the opposite side. Each segment is preferably individually supported at the frame. In its center part, the segment can be supported at the frame, for example by one or more stamps and / or one or more pillars.

[0013] According to a preferred embodiment of the present invention, a thermal insulation is provided between the segments and the frame and / or between the support element and the segment, for example to avoid heat loss and / or deformation / thermal-expansion of the frame and / or the support element.

[0014] Preferably, the segments are interconnected by connecting elements, for example screws. Preferably, two adjacent segments are connected to each other. The connecting elements are preferably provided near the circumference of the segment. Preferably, one or both moulds are heated, to support the forming of the sheet and / or to initiate the expansion of the polymeric material. According to a preferred embodiment of the present invention, a heating element, preferably an electric heating element, is provided adjacent to the forming surface of the mould, more preferably between two adjacent segments. Preferably, the heating element is provided in a groove, which more preferably extends parallel and adjacent to the forming surface of the mould and / or the segment. Preferably, the heating element is provided parallel to the forming surface of the mould. Preferably, the shape of the heating element follows the shape of the forming surface of the mould.

[0015] Another subject matter of the present invention is a method to form and expand a sheet with inventive tool.

[0016] The disclosure made regarding this subject matter also applies to the other subject matters and vice versa. Subject matters disclosed in the context of one subject matter can be incorporated into other subject matters.

[0017] According to a preferred embodiment of the present invention, for a design change of the formed and expanded sheet and / or for maintenance and / or repair / substitution, only one, two, three, four or more, but not all segments of the mould is changed, while other segments may be still used. Each segment can preferably be removed from the mould, without removing the adjacent segments.

[0018] Preferably, each segment is heated individually and / or pairwise. Preferably, each segment comprises a temperature sensor, whose signal is provided to a control system that controls the surface temperature of the segment of the mould. This allows to control the temperature of the forming surface of one or two or three adjacent segments without influencing the temperature of the other segments.

[0019] The inventive forming. And expansion-tool and / or the inventive method has the following advantages:

[0020] Raw material blocks with stand dimensions can be used, because only segments and not the entire mould must be produced.

[0021] Very large format molds can be produced with relatively small machines, for example milling machines.

[0022] Several machines, for example milling machines work at the same mould simultaneously, which is impossible with a monolith. Design changes at the formed and expanded sheet can be incorporated easily without dumping the entire mould

[0023] Easy repair of a damaged tool by replacing a segment rather than reworking the entire mould

[0024] Possibility of integrating heating as close as possible to the forming surface or the mould.

[0025] The mass of the mould can be reduced by hollowing out the rear of the useful shape (less mass = less inertia = less calorie loss)

[0026] - An electric heater which has a higher efficiency than the hydraulic network, via oil heater etc. can b utilized.

[0027] Lighter segments therefore lower moving mass and easier to move therefore less energy required in production and for the workers.

[0028] Insulation can be incorporated more easily and therefore heat losses do are reduced. Reduced preparation time due to reduced heat up times.

[0029] More precise tool temperature control by selected slice thickness of the segments

[0030] The inventions are now further explained according to the figures. These explanations apply to all embodiments of the present invention likewise. The explanations do not limit the scope of protection of the present inventions.

[0031] Fig. 1 depicts the sheet.

[0032] Fig. 2 shows the mould

[0033] Fig. 3 depicts the forming and expansion of the sheet under the influence of heat. Figs. 4 - 6 each depict an embodiment of the inventive tool.

[0034] Figure 1 shows the sheet that is formed and expanded with the inventive tool. The sheet 1 conventionally comprises at least one, preferably two cover layers 2 and an expandable layer, for example polymeric, material in between. The polymeric material is an expandable material, that preferably expands under the influence of heat. During and / or after its expansion the polymeric material preferably cross links to provide stiffness.

[0035] Figure 2 shows a tool 14 to form and expand a sheet 1. The tool 14 comprises a first- and a second mould 4, 5. Each mould 4, 5 provides a forming surface, which is a negative of the desired final shape of the sheet 1. Preferably, the two moulds can be moved relative to each other from a forming / expansion to a remote position and vice versa. In the forming / expansion position, the sheet 1 is formed and expanded. In the remote position, the sheet can be removed from the tool. Depicted in Figure 2 is the remote position. Figure 3 shows the expansion of the sheet 1. After and / or while the moulds 4, 5 are moved into their forming / expansion position, the sheet 1 is heated, for example by transferring heat from at least one mould 4, 5, the expandable layer 3 expands as depicted by the double arrows 6. This expansion can provide a force to form the sheet 1 into its desired shape. It the forming- and expansion position, there is initially a gap, which allows an expansion of the sheet 1. This gap is at least essentially closed after the expansion is finalized. Preferably, in its expanded stet, the expandable layer cures, so that the shape of the sheet 1 is maintained and the sheet is mechanically stable.

[0036] Figure 4 shows an embodiment of the inventive tool, whereas only the mould 5 is depicted. As can be seen, the mould is divided in multiple, here five segments 8. Each segment extends of the entire width of the mould and has the entire height locally needed. Together, the segments 8 provide the forming surface 15 for the sheet 1. The thickness of the segments is in the present case different, which is a preferred embodiment. By varying the thickness of the segments, for example, local temperature control, mechanical stability and / or reduced maintenance can be achieved. Each segment is provided, preferably fixed, on a frame 9, for example by screws. At the backside of the forming surface 15, material, preferably as much material as possible is removed to reduce the thermal inertia of the segment. If needed, for mechanical stability, support members 7 can be provided between a segment and the frame. Two adjacent segments are interconnected by connecting elements, preferably a multitude of connecting elements, for example screws, preferably along the entire interface of two adjacent segments.

[0037] Figure 5 shows a segment 8 with a heating element 11 , here an electrical heating element, that preferably can be controlled individually. The heating element is provided near to the forming surface 15, to allow a precise control of the temperature of this surface and / or little reaction time in case of a desired temperature change of the forming surface. The heating element 11 is provided in a groove in the contact area of two adjacent segments and heats two segments simultaneously.

[0038] Figure 6 shows a thermal insulation between the frame 9 and a segment 8 of the mould 5, which reduces heat losses and / or reduces the thermal expansion of the frame. List of reference signs:

[0039] 1 Sheet, sheet of sandwich material

[0040] 2 cover layer

[0041] 3 expandable layer

[0042] 4 first mould

[0043] 5 second mould

[0044] 6 expansion

[0045] 7 support member

[0046] 8 segment

[0047] 9 frame

[0048] 10 connecting element

[0049] 11 heating element

[0050] 12 insulation

[0051] 13 groove

[0052] 14 forming- and expansion-tool

[0053] 15 forming surface

Claims

Claims:

1. Forming- and expansion-tool (14) with a first- and a second mould (4, 5) and space (15) between the first- and the second mould (4, 5) to accommodate a sheet (1) to be formed and expanded, characterized in, that the first- and / or the second-mould (4,5) is provided by multiple segments (8).

2. Forming- and expansion-tool (14) according to claim 1, characterized in, that the segments (8) are connected to a frame (9).

3. Forming- and expansion-tool (14) according to claim 2, characterized in, that a thermal insulation is provided between the segments (8) and the frame (9).

4. Forming- and expansion-tool (14) according to one of the preceding claims, characterized in, that the segments (8) are interconnected by connecting-elements (10).

5. Forming- and expansion-tool (14) according to one of the preceding claims, characterized in, that, characterized in, that a heating element (11) is provided adjacent to the forming surface of the mould (4, 5), preferably between two adjacent segments (8).

6. Forming- and expansion-tool (14) according to claim 5, characterized in, that heating element (11) is provided parallel to the forming surface (15) of the mould (4, 5).

7. Forming- and expansion-tool (14) according to claims 5 or 6, characterized in, that the heating element (11) is provided in a groove (13) which extends parallel and adjacent to the forming surface (15) of the mould (4, 5).

8. Method to form and expand a sheet (1) with a tool (14) according to one of claims 1 - 7.

9. Method according to claim 8, characterized in, that for a design change of the formed and expanded sheet, only a segment of the mould is changed.

10. Method according to claim 8 or 9, characterized in, that each segment (8) is heated individually and / or pairwise.

11. Method according to one of claims 8 - 10, characterized in, that for maintenance or repair only a segment (8) is replaced.

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