Vibration-assisted machining research at Fraunhofer IPT - Diamond turning and precision grinding
Forschung zur vibrationsunterstützten spanenden Bearbeitung im Fraunhofer Institut für Produktionstechnologie. Diamantzerspanung und Präzisionsschleifen
The potential for ultrasonic assisted tools with undefined and defined cutting edges is shown for grinding and turning, whereas the cutting mechanisms are different. Ultrasonic assistance for grinding tools is applied to exceed the fracture toughness and thus to induce cracks in the workpiece material. This effect can be used to increase maximum material removal rate or to lower process forces compared to a conventional grinding process at comparable process parameters. Beside the advantages unfortunately the SSD is higher for the ultrasonic assistance which has to be taken into consideration of the process strategy design. Ultrasonic assistance for ultra-precision turning is applied to decrease the excessive diamond tool wear for ductile machining of hardened steel. The kinematical consideration is the key to achieve appropriate surface conditions as well as reduced tool wear. The investigations show that the conventional parameters like depth of cut a(ind p) and feed rate f lead to similar results compared to conventional ultra-precision machining. However, a consideration of the kinematical parameters entrance duration ED and entrance speed v(ind in) is likewise mandatory and show the massive influence of the entrance duration ED regarding the surface roughness. Theoretical investigations show also the potential of higher frequencies for the ultrasonic assisted turning process.