Question

A workpiece of 200 mm long and 50 mm diameter must be machined into the length of 190 mm and diameter of 40 mm. The workpiece rotates at 500 rpm, feed is 0.2 mmrev for roughing and 0.05mmrev for finishing, and maximum depth of cut is 2.3 mm. Assume total approach and over-travel distance is negligible. Calculate the time required to finish this job for the following two machining scenarios:
a. Facing to reduce the length followed by turning to reduce the diameter
b. Turning to reduce the diameter followed by facing to reduce the length

Answer 1

Li= 200 mm 12-1gornm 2.3 mn honp a) Facin9 then turfing , L=10 mm &d=23 mm b hence, γο ughing tut & 5th (1 nishing cat 347 I O Tirm e vequired roy γ0uqh ing cuts.forPacing 0/2 For finishing F0γ turning) 人=190 mm, pi=50mm ,D2-40mm. Total depth of cut, 5 mm) 2 No. oC passes , 5mm-5-2-1783 2.3 2 γ。ughing Passes > I finishing pass 5S, min 2.

Total time titt2tta tt4 = 19.4 min b Turning then facing Turning, - 20o mm Tota l depth of cub = 5 mm. Ne.of passes. 3 2 γ0 ug hing , l finishing. Facing, d2 to Δ1:10 mm . d= 2,3 mm, again no. of passes 5 h γ。ughing. I finishing 2 O3 min, 02x500 こ0,8 min. Total time.-titt, tttt4 = 4+8 +o.gtog 13-6 min