RAPID PROTOTYPE STAMPING TOOL FOR HOT FORMING OF ULTRA HIGH STRENGTH STEEL MADE OF ALUMINUM

Abstract

A method for producing a forming tool having a forming punch and a mating die corresponding to the forming tool for forming a substrate is provided, which includes the steps of preparing at least the forming punch of the forming tool from a light metal and forming a protective coating on at least one region on a surface of at least the forming punch of the forming tool. The protective coating is applied to a region that is configured to contact the substrate, and in one form, the light metal is aluminum or an aluminum alloy. A forming tool having a forming part and a mating die is also provided, in which at least the forming tool is made from a light metal and includes the protective coating.

Claims

1. A method for producing a forming tool having a forming punch and a mating die corresponding to the forming tool for forming a substrate comprising the steps of: preparing at least the forming punch of the forming tool from a light metal; and forming a protective coating on at least one region on a surface of at least the forming punch of the forming tool.

2. The method according to claim 1, wherein the protective coating is produced by means of plasma electrolytic oxidation or plasma electrolytic deposition.

3. The method according to claim 1, wherein the protective coating is produced on the at least one surface region that is in contact with the substrate to be formed.

4. The method according to claim 1, wherein the protective coating is formed from a plurality of layers.

5. The method according to claim 1, wherein the forming punch and the mating die are produced as preforms from the light metal, wherein the preforms are finished to a final shape, wherein the protective coating is produced in one region of each final shape.

6. The method according to claim 1, wherein the forming punch and the mating die are each produced from a light metal block, wherein each light metal block is machined to give a final shape, wherein the protective coating is produced in at least one region of each final shape.

7. The method according to claim 1, wherein the protective coating is subsequently polished.

8. The method according to claim 1, wherein the protective coating is hard anodized.

9. A forming tool comprising: a forming punch; and a mating die corresponding to the forming punch, wherein at least the forming punch is formed of a light metal and defines at least one region having a protective coating that is configured to come into contact with a substrate to be formed.

10. The forming tool according to claim 9, wherein the forming punch is formed from aluminum or from an aluminum alloy.

11. The forming tool according to claim 9, wherein both the forming punch and the mating die are formed from light metal.

12. The forming tool according to claim 9, wherein the protective coating is at least one of a heat protective coating and an antiwear coating.

13. The forming tool according to claim 9, wherein the protective coating has a hardness of up to 2000 HV.

14. The forming tool according to claim 9, wherein the protective coating is applied in a uniform thickness.

15. The forming tool according to claim 14, wherein the uniform thickness is between 10 μm and 200 μm.

16. The forming tool according to claim 9, wherein the protective coating has a variable hardness.

17. A forming tool comprising: a forming part; and a mating die corresponding to the forming part, wherein at least the forming part is formed of a light metal and defines at least one region having a protective coating that is configured to come into contact with a substrate to be formed.

18. The forming tool according to claim 17, wherein the forming tool defines at least one edge on at least one of the forming part and the mating die, and the protective coating is disposed on the at least one edge.

19. The forming tool according to claim 17, wherein the forming part and the mating die are formed from a light metal.

20. The forming tool according to claim 17, wherein the light metal is aluminum or an aluminum alloy.

Description

DRAWINGS

[0035] In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:

[0036] FIG. 1 shows a temperature profile in a forming tool made of steel during hot forming operations on a body component according to the prior art;

[0037] FIG. 2 shows the temperature profile during the hot forming of a body component by means of a forming tool made of a light metal and produced according to the present disclosure; and

[0038] FIG. 3 shows a forming punch systematically in a cross section.

[0039] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

[0040] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

[0041] In the various figures, identical parts are in all cases provided with the same reference signs, for which reason these are also generally described only once.

[0042] In FIGS. 1 and 2, the Y axis denotes the temperature, wherein the X axis denotes the distance of the sheet (substrate) to be hot-formed into a body component from the forming tool 1, 2. In FIG. 1, the forming tool 1 according to the prior art, which is made of a steel, is shown only schematically. In FIG. 2, the forming tool 2 according to the present disclosure, i.e. the forming tool produced from a light metal, is shown, although likewise schematically, and has a protective coating 3. The sheet to be hot-formed into a body component has the reference sign 4 in each case. The dashed line 5 denotes the melting temperature of the light metal, e.g. of aluminum.

[0043] It is expedient if the protective layer 3 is a heat insulation layer. The expedient form is illustrated by way of example by means of an aluminum tool (FIG. 2). The sheet 4 is transferred to the forming tool 2 at a temperature following austenitization, wherein the temperature is significantly above the melting temperature of the light metal (the melting temperature of pure aluminum is about 660° C., line 5). According to the present disclosure, by way of example, an oxidation layer, e.g. the protective coating 3, is applied to the forming tool 2, e.g. at least to the forming punch of the forming tool. Ideally, the protective coating 3 is hard, has a low friction coefficient and a low specific heat conduction (e.g. about 20× lower than steel). The heat input from the sheet is thus trapped in the boundary layer or protective coating 3 of the forming tool 2 at the beginning of hot forming. As soon as the heat coming in a delayed manner from the sheet transfers to the illustrative aluminum forming tool via the protective coating 3, the aluminum, by contrast, then conducts the heat away quickly (normally 3× better than steel). Thus, according to the present disclosure, rapid quenching of the sheet 4 and hence martensitic microstructure formation can be provided.

[0044] By virtue of the low specific heat conduction of the insulation layer, e.g. of the protective coating 3, the radiant heat is also dissipated more slowly than with conventional steel forming tools (FIG. 1). This means that the sheet can expediently be introduced into the forming tool 2 according to the present disclosure at a higher temperature than with steel forming tools 1. By virtue of the higher temperature of the material, the forming forces are also reduced and formability is enhanced.

[0045] This effect can be further reinforced by bilateral application of the protective coating 3, i.e. of the heat insulation layer, to the forming punch and to the corresponding mating die of the forming tool 2.

[0046] FIG. 3 shows a forming tool 2, that is to say, by way of example, the forming punch thereof as a detail, which has the protective coating 3 according to the present disclosure. Of course, the dimensions are shown in a distorted way. The protective coating 3 is oriented in the direction of the corresponding mating die (not shown) and is arranged over the full area and with the same thickness on the forming punch, purely by way of example. The mating die too can have the protective coating 3. It is in accordance with the present disclosure that the protective coating 3 is thicker in some region or regions than in other regions.

[0047] The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.