Systemunterstützte Umformung (English shop)

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Consistently pursued lightweight design has led, and continues to lead, to increasing complexity in sheet metal forming. However, findings from research activities on the targeted influencing, control and full automation of the deep drawing process have so far not been transferable to large-scale production press shops.

For this reason, this work presents a tool concept that enables targeted local influencing of the forming process while taking the relevant boundary conditions into account. At the same time, it permits monitoring of the velocity and the draw-in path of the blank by means of a novel optical sensor concept.

A methodical procedure for the manufacture of forming tools based on the new conception is described. Forming simulations serve to identify critical components and their critical zones. A correspondingly adapted design provides installation space for the implementation of additional actuators and a defined elastic insert. Concluding FEM analyses with solid models as well as the calculation of the service life confirm sufficient flexibility and the required fatigue strength.

Within the scope of the experimental analysis, a drastic reduction of the start-up time through significantly reduced spotting effort could be demonstrated, owing to the adaptability and flexibility of the defined elastic tool concept. In addition to this potential with regard to structured commissioning, the conception enables compensation of press differences and individual machine characteristics (such as, for example, ram tilting), as a result of which the transfer from the try-out press to the production plant causes considerably fewer correction loops. Furthermore, the quality effort (re-spotting) during ongoing series production, downtimes and scrap rates are greatly reduced. Moreover, extended application possibilities arise in the forming of tailored blanks, and enormous savings and cost potentials result from the minimisation/optimisation of the blank cut.

Finally, the advantages of a closed process control loop through the linking of sensor and actuator technology are analysed. The proposed control concept of process adjustment confirms the increase in process stability under fluctuating process parameters through the targeted, local distribution of the surface pressure.

Lastly, the present contribution discusses possibilities for transferring the improvement potentials into future series production tools against the background of cost restrictions and the minimisation of operational and design effort.