Question

A slot of 25 mm × 25 min is to be milled in a workpiece of 300 mm length using a side and face milling cutter of diameter 100 mm, width 25 mm and having 20 teeth. For a depth of cut 5 mm, feed per tooth 0.1 mm, cutting speed 35 m/min and approach and over travel distance of 5 mm each, the time required for milling the slot is minute (round off to one decimal place).

Answer 1

L = 300 mm, D = 100 mm, Z = 20 teeth,
d = 5 mm, f = 0.1 mm, V = 35 m/min
A = O = 5 mm
$V=\pi DN$

$35=\pi \times 0.100\times N$

$N=\pi \times 111.408rpm$

$t=\frac{L+\frac{D}{2}+A+O}{fzN}$

$=\frac{300+\frac{100}{2}+5+5}{0.1\times 20\times 111.408}$

$=1.6157minperpass$
For 25 mm cuts min 5 mm depth of cut 5 pass needed.
Total machining time = 5 × 1.6157

$=8.078min\simeq 8.1min$