A step-by-step guide to how plastic is manufactured

A step-by-step guide of the plastic manufacturing process

Plastic is one of the most commonly used and essential materials in modern use. Everything from medical supplies to vehicles relies on plastic in some form or another, thanks to its affordability coupled with its strength and rigidity.

As demand for plastic has grown and the ways in which we use it have increased in number, the plastic manufacturing process has adapted and evolved in order to catch up. There are numerous ways to create plastic products that each have their advantages and drawbacks.

How do you manufacture plastic products?

The plastic manufacturing process starts with the ‘raw’ plastic material which is often supplied in the form of pellets. These thermoplastic pellets are melted to create the liquid state that lends itself to being extruded and moulded into various shapes.

Some methods, like CNC machining, deal with plastic in formed blocks which are then cut and shaped into the desired shapes, or sheets which may also be cut or can be heated and formed using moulds.

What are the plastic production methods?

The plastic manufacturing process can vary quite widely depending on the needs and demands of the parts being created.

Types of plastic manufacturing methods include:

Injection moulding

This involves melting plastic pellets in a plasticising unit, a hollow metal tube that houses a screw conveyor. As the unit is heated and the plastic softens and melts, the screw turns to churn up the plastic material and move it forwards into the mould.

The mould itself is machined from metal, and is filled with molten plastic that is then cooled and ejected, creating a solid part in the shape of the mould’s recesses.

Rotational moulding

Using a mould like above, rotomoulding uses molten plastic in lesser amounts so as to make a hollow part. The mould is then rotated and moved so that the recesses are coated with an even layer of plastic as the mould is heated, then cooled until the plastic has hardened in a uniform thickness.

Rotomoulding is ideal for hollow composites and parts such as containers and drums.

CNC machining

Something we’re very familiar with. Plastic CNC machining uses blocks of material and machine controlled tools to cut away layers of material until the desired shape is achieved. CNC machining is quick and efficient, with highly accurate results even when dealing with complex part geometry.

CNC tools can create threads, holes, bevels and chamfers, and many more features.

Blow moulding

Compressed gas is used to inflate molten plastic inside a mould and cooled to create a hollow part. Blow moulding uses either injection—wherein a plastic preform is stretched out with a rod then inflated—or extrusion, which puts the plastic through a die to create a thin, hollow tube which is then inflated.

Injection blow moulding can be used for creating solid parts, whereas extrusion blow moulding is for hollow parts like containers.


In the process of thermoforming, a sheet of plastic is heated until soft, then stretched out over the surface of a die or mould. Vacuum pressure pulls the plastic tightly so that it assumes its final shape until it’s cooled.

Thermoforming is unsuitable for use with thermoset plastics, which won’t soften and resume rigidity after cooling.

3D printing

3D printing has made some incredible strides over the years, but it still has a way to go before becoming a truly viable alternative in industry when compared to CNC machining and other plastic parts manufacturing processes.

3D printing can take any of several approaches. It can use fused deposition modelling which melts thermoplastic filament and extrudes it to build the part in layers. Stereolithography uses lasers to cure photopolymer resins, and selective laser sintering also uses lasers to melt plastic powder.

3D printing uses CAD models similarly to CNC machining in order to build parts up in layers. It requires a certain level of technical expertise to do reliably, and though industrial 3D printers can now work to high accuracy, parts can fail or build incorrectly, resulting in wasted time and material.

Plastic manufacturing and fabrication with GA Profiplast

Our team is up-to-date on how to manufacture plastic parts with a wide range of expert plastic fabrication services. From CNC machining to die cutting and cementing, we welcome jobs big or small with tight tolerances and high demands alike.

To learn more about our services and to send us an enquiry, get in touch today.