Milling Cutter Failure

1. Tool Breaks

(a) Incorrectly mounted or running eccentrically

(b) Excessive overhang, consider shorter tool

(c) Workpiece inadequately clamped

(d) Excessive feed or table running with cutter stalling

(e) Cutter chipped or worn. See page 47

(f) Swarf not clearing, consider different design or spiral of cutter

(g) Cutter too light for job

2. Short Tool Life

Consider items (a), (b), (c), (d)

(h) Speed too high, tool burning out

(i) Feed too light, tool rubbing (consider climb milling)

(j) Inadequate lubrication (no coolant, run at half speed)

3. Poor Size

Consider items (a), (b), (c), (g), (k).

Machine in poor condition.

If giving slot lean on slot drilling, try using a tri-cutter.

4. Poor Finish

Consider items (a), (b), (c), (d), (j), (k).

Look for one tooth doing all the work, consider climb milling.

Climb milling is where the cutter, cuts from the thick side of the chip to thin. The cutter tending to pull the workpiece into the cut, previously always avoided but modern machines can cope with this mode of cut.