Investigation on the burr formation mechanism in micro cutting

•The maximum stress area shifts from the top corner to the bottom corner of the cutting edge arc because of the dominant ploughing.•Burr size decreases to the minimum value and then increases with reducing the uncut chip thickness due to the change of maximum stress distribution.•An extra milling process with opposite feed direction and small milling width on the down milling side is suggested to remove the large top burr.

It is desirable to minimize burr formation for improving part quality. This paper presents an investigation on the burr formation mechanism in micro cutting by taking into consideration the stress distribution around the cutting edge arc. The influences of the uncut chip thickness and the cutting edge radius on burr formation were investigated. Poisson burr is attributed to the side flow of the stagnation material at the bottom of the cutting edge arc. The stress distribution at the cutting edge arc has great influence on Poisson burr formation. The burr height decreases to the minimum value and then increases with reducing the uncut chip thickness due to the change of the maximum stress distribution. An optimum machining strategy also is suggested in micro milling of snake-shaped groove microstructure.