Proudly Made in the USA  ·  Serving the USA since 1996 Mon–Fri 8am–5pm ET  ·  ed@peliton.com
Peliton Plastics logo
Home / How It's Made
The Process

How Plastic Injection Molding Works.

A plain-English look at how your part goes from raw plastic beads to a finished, packaged product — and what drives the cost of the tooling.

The Cycle

Six Steps, Repeated.

1

Clamping

The press closes the two halves of the steel mold together with great force, strong enough to withstand the pressure of the molten plastic.

2

Injection

Raw plastic pellets are fed into a heated cylinder where a rotating screw melts them and pushes a measured "shot" forward, injecting it into the empty cavity.

3

Holding

The machine holds the material under pressure so it fully packs out the part and can begin to solidify.

4

Cooling

The part cools to a solid. Meanwhile the screw rotates to build the next shot — keeping the cycle efficient.

5

Mold Open

The clamp opens, separating the two halves of the mold.

6

Ejection

Ejector pins push the finished part free. The cycle returns to step one.

What Drives Tooling Cost?

A mold (or "tool") is the biggest up-front cost. It depends on:

Part complexityGeometry
Cavities per cycleVolume
Part sizeTonnage
Tool life (aluminum vs steel)Material

Example: a single-cavity steel mold for our 9.5" promotional flying disc ran about $10,000. Don't lose hope — nearly everything around you is made of molded plastic. A good prototype, a marketing plan, and the right partner go a long way.

Anatomy of a Molding Machine

A hopper mixes color and feeds raw beads in. A heating element melts the plastic. A screw-type plunger injects the molten compound into the mold, where the part is formed. Machines are rated by tonnage — the clamping force holding the mold halves shut. Bigger parts need more tonnage.

A Little History

From Billiard Balls to Today.

Plastic was first invented in 1851 by Alexander Parkes in Birmingham, England. American inventor John Wesley Hyatt created Celluloid and patented the first injection machine in 1872 — crude by today's standards, it used a plunger to inject molten material, producing billiard balls, collar stays and piano keys. Demand exploded during World War II, and in 1946 James Watson Hendry built the first screw-type injection machine, allowing precise control of speed, quality and color. That screw-type machine is still the standard today — and it's exactly what runs on our floor.

Have a Part in Mind?

We'll walk you through the process and a complete cost analysis — no obligation.

Get a Free Quote