If wrinkles occur during the production of a component, this is a clear sign that the wrong production method was chosen or that important process parameters were not determined correctly. Often, visualizing the forming process step by step in the simulation is sufficient to detect the problem areas and to take the correct countermeasures.
Wrinkles always occur when there is a local excess of material. Strong compressible stresses then compress the material and it literally deflects into the wrinkles, if this is made possible by the process design.
Accordingly, there are numerous factors that favour the wrinkling:
Gap between sheet metal, blank holder and punch: The material has room to escape.
Low blank holder pressure: The wrinkling is not counteracted by sufficient force.
Low sheet thickness: The sheet itself does not counteract the wrinkling sufficiently.
Good material flow and low friction: Supports local excess material.
Typical measures against wrinkling are therefore to clamp the sheet metal and reduce the material flow by using smaller radii and drawbeads. However, too little material flow often leads to material failure by too excessive thinning. Therefore, numerous optimization loops are often necessary to design the process in such a way that neither wrinkles nor material failure occur.
It is much favourable to do these loops in the simulation and not on the try-out press.