( 1 ) classification by plasticizing manner , 1. plunger-type plastic injection molding machine , its very poor kneading, a plasticizer is not good, means to install torpedo. Has been rarely used. 2. Reciprocating screw type plastic injection molding machine ; relying on the screw for plasticization and injection, the mixing and plasticizing properties are very good, and it is most used now. 3. Screw -the plunger plastic injection molding machine relies on the screw for plasticization and the plunger for injection, the two processes are separated. ( 2 ) According to the mode of clamping , 1. Mechanical type , 2. Hydraulic type , 3. Hydraulic - mechanical type .