Plastic injection molding process involves the use of plastic, or polymer. The granular polymer is fed into a heated barrel. Additionally it is further melted and mixed inside the barrel with the rotation procedure for a screw type plunger, as heat is generated through the friction between polymer granules when the screw is rotating.

The double injection plastic mold is going to be forced in a mold cavity using the required final shape by way of a nozzle through the screw rotation action. The mold is comparatively cold which may have cooling channels run through it. This causes the molten polymer solidifies almost once the mold cavity is filled. The solidified part using the final required shape is going to be ejected out once the mold open again. It will probably be further cooled off by the ambient air.

Plastic injection machine is commonly used to hold the mold set up as well as melt the plastic and inject it to the mold cavity.

Injection machine is classified by it tonnage. Tonnage will be the clamping force that this machine use to clamp the mold during injection molding process. It may be ranged from lower than 10ton to 5000 tons, be determined by part size and materials used.

Another number of injection machine is be it single injection machine or double injection machine. For double injection machine, it will have 2 set of screw plunger, hoppers and nozzles.

In Medical equipment plastic mold, there injetion many common defect due to process constraint and material properties.


With better injection machine, material, skill and parts design, such defect might be overcome quite easily nowadays.