Dynamic analysis of metal forming machines

Knowledge about the material properties of the metal blanks used in the forming process plays a vital role in the manufacture of high quality metal components, as does geometric precision and the high-quality surface finish of the manufacturing dies. Special expertise is needed above all to adjust the machine parameters, for example to apply the right settings for blankholder force, the stroke length and force of the ram, die cushions and drawing punches.

 

It may therefore take some time before a new metal part complies with the required manufacturing quality. In addition, the costly forming tools may have an untypically short service life, with the result that too many of the manufactured parts prove to be of inferior quality. These problems are not always caused by defective forming tools, whose shape and dimensional accuracy can be inspected quickly with optical 3D scanning. Tool wear is influenced not only by process parameters (pressing force, ram stroke, die cushion pressure, etc.) but also by the static and dynamic interactions between the press and the tool (bending, vibration, ram return stroke, etc.). Further problems can often only be resolved by analyzing the dynamic forming process on the forming press while it is in operation.

 

However, it is difficult to analyze its rapid and complex movements with the required precision using conventional measuring systems. For this task optical measuring systems offer a clear advantage. The PONTOS system can take detailed measurements of the complex and rapid sequences that typically occur in forming processes.

 

 

This was to be followed by online analysis of a real punching process in order to test dynamic machine stiffness. The aim was to analyze not only the bend factor of rams, drawing punches and die but also the speed and any vibrations on blankholders, drawing punches and die. The ram return stroke was of special interest.