Plastic injection molding reliably creates a high volume of consistent, high-quality units, and there are several other compelling reasons to consider the process:
It enables complex metal to plastic conversions, lowering overall part costs by reducing several machining operations into a single molding process.
Plastic components are lower in weight than machined or cast metal parts.
When plastic can be used instead of metal, corrosion is no longer an issue.
Plastic injection molds allow greater design freedom for parts, because they allow the addition of radii or soft edge areas that would require extra machining (at an additional cost) in metal parts.
Another element of design freedom is the ability to create highly detailed parts with complex geometry. Because the plastic material is pushed into the mold under high pressure, it fills the cavity completely and is pressed against the mold harder than in other molding processes. The plastic will thereby conform to even tiny, intricate shapes and details within the mold.
It is also possible to combine different materials into the same part for greater utility with fewer assembly processes. With 2 shot molding, you can use a hard and a soft plastic to create a sealing edge or soft-touch edge, or use two different colors. Insert molding allows a non-plastic component to be incorporated, such as a metal screw built into a plastic cabinet knob.
The plastic injection molding process involves a high degree of automation, which can provide significant savings in production costs. Many of the steps can be completed by the machines or robotics controlled by a single operator, reducing labor costs and overhead. The process can also be performed more quickly and efficiently, increasing production output.
There is little to no material waste generated by this process, as leftover scrap plastic can be re-ground and reused.