Plastic Arm chair is beautiful, fashion in daily life and more widely used, mold in processing, steel, polishing and other aspects are very important. The arm chair die steel is generally the mold cavity and core P20H. The plastic chair die is generally a large gate, using a cold runner and a thimble ejector. At the same time, the backrest design of the chairs can be replaceable directly on the machine. In this way, it can save a lot of time. Therefore, it is necessary to analyse which areas of the chair mold need to be vented through the mold flow before production.