With the continuous improvement of automobile manufacture technology, aluminum alloy materials are more and more widely applied in auto parts. But some cast aluminium have a certain number of parts with poor surface roughness at the beginning of the cutting and machining process.

Common machining surface roughness of cast aluminium is due to the size of the cutter, auxiliary angle and supply quantity. During the cutting process, built-up edge, scale of metal cutting surface, tool wear and cutting vibration will generate poor surface roughness. In addition, some cast aluminium are in another processing status which is not a kind of ideal phenomenon when using new cutting tool at the beginning cutting process. There are small shrinkage cavities on the casting surface.

At present this kind of shrinkage cavities in manufacturing are perceived as casting defects in the casting process. During the cast aluminium process, small shrinkage cavity is not only the result of the blank casting but also the result of sharp edge of cutting tools.

How to solve the negative influence on the cast aluminium surface roughness produced by the sharp edge of cutting tools to avoid unnecessary waste and how to correctly understand and analysis the machining processing are significant jobs of foundry workers.