Process parameters

With each method planning, the tool designer is faced with the decision of how to select the process parameters. He must make decisions regarding:

  • material
  • geometry of the tools
  • press force
  • blank holder forces
  • friction
  • initial contour of the blank outline


It is important to know that in production, these parameters are subject to so-called noise, i.e. small unpredictable fluctuations. This noise results for example from tool wearing, changes in lubrication or the fact that not every batch of material is of the same quality. It is therefore the task of the tool designer to develop the process in a robust way, i.e. that the part quality does not suffer from the small changes of the process parameters. Unfortunately, this issue is almost impossible to be tested with prototype tools, since one would need several setups and since every prototype is on its own complex and cost-intensive.

In contrast to this, simulation offers outstanding possibilities, because the input data can be changed easily and the corresponding result is immediately available. In addition, in contrast to the physical test, you get back a degree of failure between 0% and 120% and thus you can determine with great certainty how far away you are from failure. If, for example, the degree of failure is at a maximum of 90%, the tool designer can be sure that he is working with a robust method.

Difference between material batches

In this example, the end customer successfully produced a critical method in Germany after a successful simulation. When switching production to another continent, fluctuations in material quality were expected. Therefore, tensile strength and maximum elongation were slightly varied in the simulation.


With this simulation, one immediately recognizes that the process does not have the necessary robustness. If the material quality changes slightly, the simulation predicts a material failure. Consequently, the method had to be designed less borderline in order to be able to produce safely on both continents.