In the injection plastic mold process, thermoplastic resins are melted and the melt is forced (injected) into a mold. After this melt cools until the polymer solidifies, the parts are removed (ejected) from the mold.

Injection plastic mold permits mass production netshape manufacturing of high precision, three-dimensional of plastic parts. One of the most common plastics manufacturing processes, injection plastic mold can produce parts weighing as little as fraction of a gram or as much as 150 kg. The process currently consumes 30% of polymeric resins of which 90% are thermoplastics (i.e., capable of being remelted)

Major advantages include capabilities to produce parts with:
1) virtually unlimited complexity
2) fine details and good surface appearance
3) controlled wall thickness and excellent dimensional stability, and 4) requiring limited or no finishing.

The five important M¡¯s in the injection plastic mold process are the

1. Injection plastic mold machine

2. Mold

3. Material

4 Method

5. Man (i.e., operator).

While there are many variations of each M, this discussion is limited to single-stage reciprocating screw injection machines and the flow of thermoplastic polymer melts in two-plate cold runner molds.

1. Injection plastic mold Machines

As illustrated injection plastic mold machines have three major components: the 1) injection unit, 2) clamping unit, and 3) controls. The injection unit plasticates (melts) and injects the polymeric material into the mold. The clamping unit supports to the mold and provides the mechanisms for opening and closing of the mold and for ejection of molded parts.

During a thermoplastic plastic mold cycle, the clamp of the injection plastic mold machine closes, thereby closing the mold. Molten plastic located between the nozzle and screw in the barrel of the injection unit is forced (by the screw) into the mold. The controlled volume of melt injected into the mold typically fills the cavities to about 95