Selection of Back Engagement
When rough machining, in the case of rigid process system and the power of machine tool, it is necessary to take the larger back engagement to reduce the number of load. During fine processing, the machining accuracy and surface roughness of the parts should be ensured. On the basis of the surface quality requirements, tool materials, work-piece materials and machine tool performance, the cutting volume manual or relevant information is referred to: Coarse car outer contour αp=2mm, half fine car outer contour αp=0.75mm, fine car αp=0.4mm; Rough boring αp=1mm, fine boring αp=0.3mm.
Section of Load
In rough machining, according to the machining material, the size of the tool, the diameter of the work-piece and the determined back engagement, the cutting volume manual or relevant data, combined with the machine tool instruction manual, selecting: Half fine car f=0.15mm/r, fine car f=0.1mm/r, fine boring f=0.1mm/r.
Selection of Spindle Speed
On the grounds of the confirmed back engagement, feed quantity and durability of work-piece and tool material, referring to the cutting amount manual or relevant information, and table look-up, select the cutting speed Vc, coarse car Vc=120m/min, half fine car Vc=130m/min, fine car Vc=140m/min, rough boring Vc=60m/min, fine boring Vc=70m/min, and calculate the spindle speed with formula (2-5).
Vc =πdn/1000 (2-5)
In this formula: n is the revolving speed of the work-piece or cutter (r/min).
Vc is the cutting speed (m/min)
D is the rotary diameter of the work-piece or cutter corresponding to the selected point of cutting edge(mm).
Combined with practical experience, the final spindle speed is determined: Roughing machining n=600 r/min, half fine car n=800 r/min, fine car n=1000 r/min, fine boring n=700 r/min, threading n=500r/min.
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