This happens because the early to die (product model) there is no reasonable processing, so before the open mold to mold processing, such as the surface of the kind of relatively coarse or do very complicated mould, must be carefully polished smooth and clean.Then brush evenly on release agent.Commonly used mold release have vaseline, detergent, liquid paraffin, etc.Practice according to the modulus of the material of coating different release agent.