Conventional diamond millstone for gem processing has shortcomings of diamond grains easily pulled off, unstable running and low grinding speed.

Through an experiment of grinding polycrystalline diamond (PCD) by diamond grinding wheel, the influences of grinding speed v s on PCD material removal rate Q and grinding consumption ratio G are researched.

The effects of the grinding speed on the surface quality of workpieces were analyzed with the equipments.

After defining nominal cutting velocity,relative cutting velocity,and actual cutting velocity when using a rotary cutting tool,the authors have explained their functions and the interrelations on theoretical basis.

These parameters include cutting velocity 10～20m/min, cutting deepness 0.

Applying the concept of relative cutting velocity, the expression of velocity type dynamic cutting force and the mechanics model of chatter vibration in turning or boring process were advanced.

A useful computation method of optimum cutting speed and feed rate;

The effects of cutting speed and feed on residual stress of workpiece machined should be studied to improve surface quality in machining.

Turning test with thee different tungsten carbide tool have be done at cutting speed 40,80,120,160 m/min,the relationship between cutting force and cutting speed,cutting distance was analyzed,the influence of working cutting edge angle on the stability of cutting system was investigated as well.