With the sharp corners of the plastic parts in molding, often cause the local stress concentration in the corner, cracking or fracture, the stress or shock to you, in order to avoid the occurrence of such a situation, in addition to the use of plastic parts requires sharp corner, the rest are used as far as possible the arc transition. The arc transition first can increase the appearance of plastic parts, then can increase the intensity of plastic parts, also can greatly improve the flow characteristics of mold filling. In addition, the corresponding round plastic parts in die also rounded, so as to increase the robustness of mold, to a certain extent reduce the mold heat treatment or use due to stress concentration of cracking conditions.
  Fillet radius ideal should be more than 1/3 of wall thickness. Usually, the plastic inner radius is half of the wall thickness, outer wall corner radius is 1.5 times the thickness radius, the general should not be less than 0.5mm, two wall corner wall thickness can be determined according to the average wall thickness of inner, outer fillet radius. For some parts of the plastic parts such as the parting surface, core and cavity is made of rounded corners with inconvenient, can only use sharp.