In general, the number of blades is small, the chip is large, the chip discharge can be smoother, but at the same time, the cross-sectional area of the tool is small, the rigidity of the cutter body is low, and the cutting of the cutter body is easy. On the contrary, when the number of edges is increased and the cross-sectional area of the tool is increased, the rigidity of the cutter body is increased, but the chip flutes become smaller, the chip storage capacity is lowered, and the chip clogging is easily guided to reduce the surface finish of the workpiece. The shorter the blade, the greater the rigidity of the tool body, the better the cutting performance. The rigidity of the end mill is inversely proportional to the third power of the blade length (length). Therefore, the blade length (hanging length) if doubled, the rigid body will be reduced to the original 1/8.