Analyse von Größeneinflüssen bei einer Herabskalierung des Fräsprozesses in den Mikrobereich

(Analysis of Size Influences for a Downscaling of the Milling Process into Microdimensions)

Kahnis, P.

Micromilling is considered to be a suitable technique for a cost-efficient manufacturing of microstructured parts in small or medium batch sizes like, for example, moulds for micromoulding processes. A downscaling of the milling process into microdimensions leads to new problems compared to machining in macro¬dimensions. Especially occurring size effects prevent the transfer of processes and process conditions, which are well tried in macrodimensions, into microdimensions.

In this thesis fundamental investigations on effects of a downscaling of tool diameter and process parameters into microdimensions are presented. Starting with an analysis of the tools and their cutting edge geometry, the influence of the scaling on the process was determined by analyzing the cutting forces, the chip formation, and the machined surface quality. The adaptation of a geometrical simulation of the cutting forces, which is used successfully in macrodimensions, allows to increase process reliability by predicting critical process conditions before the machining process. By investigating the tool deflection, another problematic area was identified, which has to be considered, especially when machining with small tool diameters. For this, options to decrease the effects of tool deflections on the accuracy of the machined contour are presented. Furthermore, the results of this work show the influence of a downscaling on the process dynamics and point out that machining with high process reliability requires the use of optimal process parameters to avoid negative effects of tool vibrations as well when milling with small tool diameters.

Published as

Dissertation Technische Universität Dortmund, Vulkan Verlag, Essen, 2008, ISBN 978-3-8027-8745-4