Mechanical Engineering - Production Engineering - Discussion

This is the first time am hearing negative relief angle. I think it is a negative rake angle. And the negative rake angle is used when machining hard materials.

Relief angle can't be zero or negative, so here should be negative rake angle which is used for hard and brittle materials.

Rake angle will be POsitive as the workpiece is soft and RELIEF angle will negative means below ZERO ANGLE LINE (X-AXIS). Here, negative means sign convention not actual value.

Relief angle never negative. It lie between 3-15 degree.

Small relief angles are essential when machining hard and strong materials, and they should be increased for the weaker and softer materials. A smaller angle should be used for interrupted cuts or heavy feeds, and a larger angle for semi-finish and finish cuts.