Process monitor for open die forging

Abstract

A method for monitoring and controlling open die forging processes, includes: a) calculating the geometry evolution of a workpiece during open die forging using empirical models; b) in parallel with step a), that is to say at the same time or at least partially overlapping times as step a), calculating the workpiece temperature across the cross-section of the forged workpiece; c) calculating the distribution of the change in shape over the length of the workpiece, preferably by using the geometry evolution calculated in step a); and d) manually or automatically controlling the distribution of the change in shape in a predefined region on the basis of the distribution of the change in shape calculated in step c).

Claims

1.-15. (canceled)

16. A method for monitoring and controlling an open die forging process, comprising: a) calculating a geometry evolution of a workpiece during open die forging using empirical models; b) at a same time or at least partially overlapping in time with step a) calculating a workpiece temperature across a cross-section of the workpiece; c) calculating a distribution of a change in shape over a length of the workpiece; and d) manually or automatically controlling the distribution of the change in shape in a predefined region based on the distribution of the change in shape calculated in step c).

17. The method as in claim 16, wherein calculating the distribution of the change in shape over the length of the workpiece is performed by using the geometry evolution calculated in step a).

18. The method according to claim 16, wherein step a) further comprises defining a start line and an end line for the open die forging process.

19. The method according to claim 18, wherein step a) further comprises correcting the geometry evolution.

20. The method according to claim 16, wherein step b) further comprises measuring a workpiece temperature by a pyrometer or a thermographic system.

21. The method according to claim 20, wherein step b) further comprises regulating the open die forging process for maintaining a predefined workpiece temperature range.

22. The method according to claim 20, further comprising using the measured workpiece temperature as a comparative variable in a calculation model, wherein the calculation model calculates the temperature distribution over an entire cross-section of the workpiece and over a length of the workpiece.

23. The method according to claim 20, further comprising monitoring a material-dependent maintaining of a predefined workpiece temperature range.

24. The method according to claim 20, wherein the method does not use any measurement data other than measurement of the workpiece temperature and measurement signals of an open die forging press and/or a workpiece manipulator selected from the group consisting of a press stroke, a press force, and a manipulator position.

25. The method according to claim 16, wherein steps a) to c) are calculated online during the open die forging process.

26. The method according to claim 16, wherein the workpiece is a round block, a stepped shaft, a conical cast block, and/or has partially forged-over regions.

27. The method according to claim 16, wherein calculating the geometry evolution comprises calculating a stretching and spreading behavior of the workpiece in a material-dependent manner.

28. The method according to claim 16, wherein variables calculated in step a) for the geometry evolution are used as input variables for a change of shape model, and wherein the distribution of the change in shape and, in case of an inhomogeneous distribution of the change in shape over the cross-section and/or the length of the workpiece, a core compaction are ascertained.

29. The method according to claim 16, further comprising providing a control and regulation unit, wherein the control and regulation unit is connected to a database, and wherein all recorded measurement data and calculated parameters are stored in the database.

30. The method according to claim 29, wherein the control and regulation unit displays the calculated variables of geometry distribution and/or distribution of the change in shape and/or temperature distribution to an operator, issues warnings in the event of deviations from a target state, due to a region having too low a change of shape, and/or issues suggestions for regulating the open die forging process for maintaining the predefined ranges and/or achieving an ideal distribution of the change in shape.

31. An open die forging press, wherein the open die forging press is connected to a control and regulation unit, and wherein the control and regulation unit is configured to perform the method according to claim 16.

32. The open die forging press according to claim 31, wherein the control and regulation unit is connected to a database in which all measurement data recorded by sensors and parameters calculated by a change of shape model can be stored.

33. The open die forging press according to claim 31, wherein the control and regulation unit is connected to a display unit, by which the calculated variables of geometry distribution and/or distribution of change in shape and/or temperature distribution can be displayed to an operator.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The invention is explained in more detail below with reference to two figures, in which preferred embodiments of the invention are explained in more detail.

[0030] FIG. 1 shows a first view of an open die forging press at the start of the open die forging process.

[0031] FIG. 2 shows a view of an open die forging press at the end of the open die forging process.

DETAILED DESCRIPTION

[0032] FIG. 1 shows an open die forging press 1 with two forging tools 2, 3 arranged so that they can move relative to one another. The upper forging tool 3 is arranged movably against the lower forging tool 2 within the open die forging press 1, wherein the workpiece 4, held by a forging manipulator 5, is brought to the forging tools 2, 3 at the start of the open die forging process. At this point in time, a start line 7 is defined, which defines the start of the workpiece 4 or at least its length to be forged.

[0033] FIG. 2 shows the same open die forging press 1 as in FIG. 1, wherein the workpiece 4 has been completely formed between the forging tools 2, 3 at the end of the open die forging process. At this point in time, an end line 8 is defined, which defines the end of the workpiece 4 to be formed. The elongation L of the workpiece 4 during the open die forging process can then be determined from the difference between the start line 7 from FIG. 1 and the end line 8. From this, a person skilled in the art can also determine the material-dependent spreading B based on the mass and volume constancy. During the forging process, the geometry evolution can be calculated using the pass schedule carried out during the forming of the workpiece 4 and known relationships regarding spreading. Such material-dependent relationships are sufficiently known to a person skilled in the art, for example, from Tomlinson, A; Stringer, J. D.: Spread and elongation in flat tool forging from the Journal of the Iron and Steel Institute 193, 1959, pp. 157-162. As a result, it can be avoided that errors caused by unknown workpiece behavior arise, which would otherwise accumulate continuously.

LIST OF REFERENCE SIGNS

[0034] 1 Open die forging press [0035] 2 Forging tool [0036] 3 Forging tool [0037] 4 Workpiece [0038] 5 Forging manipulator [0039] 7 Start line [0040] 8 End line