Machining of hardened steel with cBN end millEndurance data

TECHNICAL

2014年12月8日

Machining of hardened steel with cBN end millEndurance data

Machining of hardened steel with cBN end mill

Endurance data – Cutting test using cBN radius end mill

Purpose of test
A cBN radius end mill was tested for slot machining in hard materials, which is a difficult process with conventional carbide end mills due to their machining inefficiency and limited tool life.

Test environment
Machine	YBM-640V
Work material	SLD(HRC60)
Cutting fluid	Oil mist
Tool used	cBN radius end mill (φ1 × R 0.1 × 6 (effective length)), manufactured by Kyowa

Test description
Cut slots 1 mm wide by 6 mm deep in a block measuring 80×60×30 mm, followed by visual evaluation at 200× magnification.

Machining conditions
Spindle rotational frequency	：18,000rpm（56.5m/min）
Feed speed	：500mm/min（0.013mm/tooth）
Cutting	:10 μm × 600 strokes per slot
Cutting length	:80 mm × 600 strokes = 48000 mm (48 m) per slot
Machining time	:1 h 42 min per slot

Test results
A cBN radius end mill was able to cut ten slots 1 mm wide by 6 mm deep by 80 mm long in a hard material. However, beginning with the fifth slot, traces of wear or chipping can be seen at the corners. The total cutting length attempted in this test was 48 mm × 10 slots = 480 mm, but a practical length is 48 mm × 4 slots = 192 mm. (Only one slot can be cut with a carbide end mill.) However, increasing the cutting speed (1.5 to 2 times faster) would provide more favorable conditions.