Method for forming a sheet blank as a workpiece in a forming tool

Abstract

A method is provided for forming a flat metal blank as a workpiece in a forming die. The method may include providing a forming die with at least one cavity, and providing at least one blankholder for fixing a flat metal blank to the at least one cavity during the forming. The method may also include heating the flat metal blank to a solution heat treatment temperature specific to the flat metal blank while maintaining the forming die at the solution heat treatment temperature. The method may also include forming the workpiece from the flat metal blank at the solution heat treatment temperature.

Claims

1. A method of forming a workpiece from a flat metal blank in a forming die, comprising the steps of: providing a forming die with at least one cavity; providing at least one blankholder for fixing the flat metal blank to the at least one cavity during the forming; heating the flat metal blank to a solution heat treatment temperature specific to the flat metal blank; disposing the heated flat metal blank in the forming die while the forming die is set to the solution heat treatment temperature specific to the flat metal blank; and forming the workpiece from the flat metal blank at the solution heat treatment temperature, while selecting a pressure of the at least one blankholder onto the flat metal blank to enable the material of the flat metal blank to be drawn from a region below the at least one blankholder into the at least one cavity, and/or while actively pushing the flat metal blank above a lower tool frame into the at least one cavity.

2. The method in accordance with claim 1, wherein the heating of the flat metal blank is concluded before the start of the forming.

3. The method in accordance with claim 1, wherein the heating of the flat metal blank is completed before introduction into the forming die.

4. The method in accordance with claim 1, wherein the workpiece is removed from the forming die and is supplied to a hardening process after conclusion of the forming and/or after conclusion of the solution heat treatment process.

5. The method in accordance with claim 1, wherein the forming takes place under gas pressure and/or mechanically.

6. The method in accordance with claim 1, further comprising a step of providing a sealing element for gas forming to minimize the outlet of gas between the flat metal blank and the at least one cavity, or the flat metal blank and the at least one blankholder.

7. The method in accordance with claim 1, wherein subsequent to the forming, the workpiece is captured by the at least one blankholder to prevent entry of the flat metal blank material into the at least one cavity for a calibration of the workpiece in the at least one cavity, the calibration being provided by a high gas pressure up to 1000 bar.

8. The method in accordance with claim 1, wherein a cycle time between the charging of the forming die with the flat metal blank to be formed and the removal of the formed flat metal blank from the forming die amounts to ? a minute.

9. The method in accordance with claim 1, wherein the heat treatment temperature follows a heat treatment temperature profile.

10. The method in accordance with claim 1, wherein a cycle time between the charging of the forming die with the flat metal blank to be formed and the removal of the formed flat metal blank from the forming die amounts to ?20 seconds on forming under gas pressure.

11. The method in accordance with claim 1, wherein a cycle time between the charging of the forming die with the flat metal blank to be formed and the removal of the formed flat metal blank from the forming die amounts to ?10 seconds on a mechanical forming.

12. The method in accordance with claim 4, wherein the hardening process comprises a cooling process and/or a further forming process in a further forming die.

13. The method in accordance with claim 11, wherein the cycle time is between 4 and 8 seconds.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be described in more detail below by way of example with reference to the drawings. There are thus shown

(2) FIG. 1a and FIG. 1b show a forming press for forming a metallic flat blank using mechanical forming and additionally with gas pressure forming;

(3) FIG. 1c to FIG. 1e show a forming process of a flat metal blank in three steps in different tools; and

(4) FIG. 2 shows a forming press for the forming of a hollow body blank.

DETAILED DESCRIPTION OF THE INVENTION

(5) In detail, the cavity or die is shown by 2 and the punch by 3 in the forming press 1 of FIGS. 1a-1e. A gas supply is schematically indicated by 4. The flat metal blank has the reference numeral 10.

(6) In this connection, a cavity or die and a punch for a purely mechanical forming of the flat metal blank 10 results from FIG. 1a. A blankholder for the flat metal blank has the reference numeral 6.

(7) FIG. 1b shows a mechanical forming in combination with a gas pressure calibration, with here a gas supply 4 being provided in the region above the flat metal blank, that is in the region of the punch 3. A blankholder 6 is also provided here. The blankholder applies a pressing force onto the flat metal blank in conjunction with the cavity or die 2.

(8) FIG. 1c shows a forming press in which the forming takes place by internal gas pressure in a first forming step. An internal pressure of, for example, 20 bar can be provided here, and indeed in dependence on the wall thickness and on the material, with material being able to be pushed into the cavity actively above the lower tool frame 5 in order to have sufficient material available, for example in a subsequent cold forming.

(9) FIG. 1d shows a purely mechanical forming as a second forming step using a punch 3 and a cavity or die 2, with the material of the workpiece being able to be freely tracked. A free material feed is also spoken of here.

(10) In FIG. 1e, a gas feed 4 into the space above the punch 3 is in turn provided for calibration in the third forming step, with the surface of the formed component being smoothed with a closed die at a high pressure of up to approximately 1000 bar, advantageously up to 200 bar, with sealed marginal regions. No material advance into the cavity takes place here.

(11) FIG. 2 shows a forming press 1 having two die halves 2 for forming a hollow body blank 11. The hollow body blank is supported in the region between the die halves, with the cavities forming the negative mold for the final form formed from the hollow body blank. The blank sealing and blank feeding or locking apparatus 12 engages laterally at the hollow body blank. The locking apparatus 12 comprises a sealing cylinder 13 at each of the two sides of the hollow body blank that is also able push material of the hollow body blank into the space between the two cavities. At least one of the cylinders 13 can have an opening 4 for supplying a gas for forming the hollow body blank.

REFERENCE NUMERAL LIST

(12) 1 forming press 2 cavity or die 3 punch 4 gas supply 5 lower tool frame 6 blankholder 10 flat metal blank 11 hollow body blank 12 locking apparatus 13 cylinder of the locking apparatus