Plastic Injection Molding Process

Injection Molding Machine

23% of all plastic products in the world are processed by injection molding. So it is very important process used in plastic manufacturing. Different types of the plastic products in different ranges which we meet in day today activities are made up using injection molding such as chairs, jars, baskets,  car parts, TV and computer housings, packaging and bottle caps etc. the reason is this process is suitable for the mass production of parts, parts having complex shapes and having precise dimensions.   

 

Injection molding process is as follows,

1. Plastic granules are fed into the machine through a hopper.
2. That plastic granulates are melted and mixed in the barrel
3. The screw is drawn back when collecting plastic melt and is then driven forward, forcing the plastic melt into the mold
4. Object is cooled inside the mold.
5. The mold is opened and the part is pushed out using ejector pins.

This process is a cycle genarally going from 30 to 120 seconds,

Major parts in injection molding process,

Injection machine: Its functions are heating, melting, collecting, forcing forward and injecting. So this part includes a screw, heaters, barrel, nozzle, hopper and hydraulic system.

Injecting nozzle: nozzle is fixed to the end of the barrel. There are two types nozzles called open nozzles and closed nozzles. 

Clamp: generally hydraulic clamping and toggle clamping are used in clamp. Toggle clamping has lower initial cost and lower operating cost compare to the hydraulic clamping method. But hydraulic method has unlimited stroke potential weather it is limited in toggle method.