Analysis of the cutting process for milling of marble and sandstone with an end mill cutter

Abstract

Research has shown that it is possible to machine natural stone materials using end
mill cutters with geometrically defined cutting edges as they are used in metal cutting
processes. The milling process can be used as an energy efficient alternative to the
well-known grinding processes. A study of Fraunhofer IPK investigates the cutting
process for Postaer Sandstone and Carrara Marble using an end mill cutter. A high
speed video camera was used in order to analyze the cutting process. The produced
stone particles (“chips”) were sorted according to their size distribution and the
resulting surface roughness was measured in order to identify possible influences of
different cutting parameters. For the study, the depth of cut ap, the feed per tooth fz
and the cutting speed vc were varied. For the influence on the surface roughness,
results show that all three parameters have a significant influence when machining
marble. For the machining of sandstone, no significant influence has been identified.
The distribution of sandstone particles after the milling process is independent from
the cutting parameters as well, only the depth of cut shows an influence for marble.
The high speed videography of the cutting process shows obvious differences
between the two investigated natural stone materials. The chip formation for Carrara
Marble is a rather continuous process whereas for sandstone the cutting process is
rather random and can hardly be influenced by altering the process parameters.