Small diameter hole product problem, usually in product design should be avoided

Small diameter hole product problem, usually in product design should be avoided, otherwise, it will cause great difficulties for product manufacturing. This difficulty in the production of the performance of several aspects: a drill easily broken, two drill deflection, easy centering three drill burns, surface quality is poor. For  polycrystalline diamond  of phenomena we analyze the reasons, so as to solve problems. A bit easy to break infarction is the most important phenomenon of such cutting tools , it is because exposure to excessive torque drill, namely radial force is too large. Drill radial force suffered from two aspects, one is part of the drill tip cutting force, on the other hand from the drill hole wall edges and friction.  Diamond blade angle head often take 118-120 degrees, the test proved that when the drill diameter is less than smm, drill angle within this range appear to be too small, resulting in excessive cutting force. Theoretically, the greater angle value is taken, the smaller the cutting force, bit more difficult to break, but the angle is too large when the value is taken, the drill bit will increase the deflection phenomenon.