Vergleichende experimentelle und numerische Untersuchungen zum schwingungsüberlagerten Pressen zweier Pulvermaterialien

The pressing process is of special importance for the production chain of powder-metallurgically produced components because in this production step the density distribution and thus the specific characteristics are set significantly. Especially the inevitable friction between the forming tools and the powder body leads to density gradients, which in turn cause sintering distortions and thus inhomogeneous material properties within the component. Therefore, the aim of the presented work was the systematic investigation on powder pressing with superimposed oscillations for the production of powder-metallurgically produced components in order to reduce friction-related density gradients. Subjects of the investigations were an aluminum powder (Alumix 13, ECKA) and a mixture of a abrasives and bond (Comet grinding wheels) as it is used for the production of ceramic bond grinding wheels. The results allow different material-related conclusions regarding the positive effects of superimposed oscillations on the pressing process. Thus, the existence of a favorable oscillation frequency of about 60 Hz for the investigated abrasive/bond mixture could be proven. Above that, experimental and numerical investigations showed that, with an adequate oscillation frequency, density distributions can be achieved which otherwise can only be observed for the significantly more complex double action pressing.