Powder metallurgy solutions for soft materials

CBN tools are widely used because of their high hardness, good wear resistance, thermal stability and chemical properties. However, due to the brittleness of CBN material, it is usually necessary to treat the cutting edge to improve its chipping resistance when machining products with high hardness, and the most common is to grind negative chamfer on the cutting edge.

Machining a soft material powder metallurgy products, hardness of HB100, due to the characteristics of the powder metallurgy material, macro hardness is not high, but the micro hardness is very high, so we at the beginning of the design of the tool chamfering design of -15 °, so as to improve the tool chipping resistance, so as to increase the service life of the tool. However, the results of the field test were not satisfactory, and the surface finish of the product decreased after processing for a period of time, reaching the limit value.

According to the machining situation and tool analysis is due to the tool is not sharp enough, cutting is not fast enough to cause this phenomenon, WSS technical team believes that the CBN tool in the processing of the material hardness of the softer case, negative chamfering will increase the cutting resistance, the resulting phenomenon of sticking chips make the surface finish deterioration. We then cancelled the chamfering design, applied the new tool design scheme and tested it again, the machining effect achieved the expected results, and the service life was also greatly improved. The same design scheme was tested several times, which was well verified, and the processing results were recognised.