"From thick to thin"
There are 3 distinct phases to be considered in the intermittent contact between each cutting edge of the milling cutter and the workpiece:
cut in
cutting arc
Cut out
Carbide tools are able to withstand the compressive stresses that occur when cutting into the wall of a part on impact.
The sudden release of the tensile stress of the workpiece after cutting out the compressive stress will lead to a significant shortening of the tool life.
Therefore, it is recommended to use down milling, and the iron filings change from thick to thin when cutting
