1, in the plastic mold, it is also the most commonly used to separate the product from the mold; 2. Cemented carbide thimbles, such as tungsten steel thimbles, can be used to pass through elongated holes; 3. thimble is also called tip. It is a conical metal round bar with head assembled on lathe or grinder, which is used to support the workpiece and make it rotate around it, but it is completely different from the thimble of plastic mold parts. 4, plastic mold thimble can also be used in the mold, it can play a stable role, called insert needle. The types of plastic mould thimbles are: flat thimble, dome thimble, supporting thimble, standard thimble, non-standard thimble and so on. The materials of plastic mould thimble are SKH5 1, SKD6 1, SKD1,65Mn, etc. The toughness of SKH5 1 thimble is better than SKD6 1. SKD6 1 thimble can withstand the high temperature of 1600℃. After nitriding the surface of SKD6 1 thimble, the wear resistance of thimble can be well improved. Because of the poor quality of 65Mn thimbles, which are brittle and easily broken, most plastic molds have not been assembled and used with 65Mn thimbles.