Tribological mechanisms, process optimization and surface design

Tribology with its subsections friction, lubrication and wear is an inherent part of research and development at the PtU. On one hand, comprehension of this fundamental area is an important subject. On the other hand, valuable results for industrial applications are obtained by working on application-oriented researches. The forming processes considered include deep drawing and stretch forming under cold and hot forming conditions, shear cutting, and cold massive forming.

Working on tribological process optimization, it is important to realize friction conditions between tool and workpiece. It is crucial to have them as homogeneous, constant and well-defined as possible. Furthermore, it is necessary to minimize the tool wear. A major precondition is the basic comprehension of appearing friction and wear mechanisms. Based on this, optimization methods can be derived, taking in consideration the whole tribological system, ranging from the semi finished part over the lubricant to the tool. In addition, active and local modifications of the contact zone are important parts, too. Finally, detected dependencies can be described in friction and wear models, providing a valuable input for more precise numerical simulations.

Workpiece surfaces are gaining increasing importance. On one hand they give a functional property to the produced workpiece; on the other hand they influence crucially the affective friction mechanisms during the forming process in the forming zone. For the creation of convenient surfaces on semi finished parts, the mechanisms, leading to surface changes during forming processes, must be known. Furthermore, the transfer of gained knowledge on forming processes with different load profiles is of interest.

The fundamental experimental investigation of tribological circumstances about specific forming processes requires mapping of occurring tribological load profiles in model experiments. Under laboratory conditions, test stands offer on one hand the accessibility for measurement systems, on the other hand the defined and selective adjustment of tribological loads. Besides experimental researches finite element method (FEM) is used, which allows the analysis of the tribological loads in the forming zone.