PROCESS

This is perhaps the most widely used of all plastic processing methods. The machine consists of a heated barrel with a rotating screw inside, which reduces pelletized raw material and colorant into a hot liquid. This "melt" is forced into a 2-piece water cooled mold under tremendous pressure. After the plastic solidifies, the mold is unclamped and a finished part is ejected.

RAW MATERIALS

Most raw materials can be used. The resin is in pellets before processing. 

TOOLING

Because of the high pressures involved in this process, steel tooling is preferable. Aluminum may be used for low volumes and prototyping.

COST

Injection molding offers the lowest piece prices available, but tooling prices are generally the highest.

ADVANTAGES

The marketplace is saturated with injection molders, so end users can usually get low piece prices. Equipment available in all geographical locations. Lends itself to most types of designs. 

DISADVANTAGES

High tooling cost. 

EXAMPLES

Containers, household goods, auto components, electronic parts, flower pots.