Figure 5-5 shows the shape of the cutting layer during cylindrical milling cutter and face milling. The cutting layer thickness hp is the distance between the main cutting edge trajectories of two adjacent cutter teeth measured within the base plane. The formula for calculating the thickness of the cutting layer for circumferential milling and face milling is:
Circumferential milling h(d) =∫(z) sin φ (5-1)
End milling h(d) =∫(z) cos φ sinK(r) (5-2)
Entering angle K(r)
Tooth rotation position angle φ
It can be seen from equation (5-1) and equation (5-2) that the thickness of the cutting layer h during milling changes with the angle φ of rotation of the cutter tooth, that is, the different position of the cutter tooth. In the case of circumferential milling, the cutter tooth is at the starting position at the day point of HP=0, which is the minimum value; When the cutter teeth are about to leave the workpiece and reach point A, the cutting layer thickness is maximum. In end milling, the thickness of the cutting layer is the smallest when the tooth is first cut into the workpiece, the maximum in the middle position, and then gradually decreases again. Due to the constant variation in the thickness of the cutting layer, the cutting forces fluctuate more during milling than in turning.
Figure 5-5 The shape of the cutting layer during machining
a) Circumferential milling b) Milling
