Plastic processing vs. plastic machining: what is the difference?

The terms "plastic processing" and "plastic machining" are often used synonymously, although they describe different processes and areas of application.

This article highlights the differences between these two methods and provides you with a sound basis for choosing the right method for your requirements.

What is plastic processing?

Plastic processing describes the process in which raw materials are formed into finished plastic products, such as plastic sheets. These are generally large-scale industrial processes that guarantee high efficiency and production volume. Typical plastic processing methods are:

• Injection moulding: Plastic granules are heated, liquefied and injected into a mould.
• Extrusion: Plastic is pressed through a die opening to produce long profiles such as pipes or films.
• Blow moulding: Here, plastic is forced into a mould by compressed air, e.g. for bottles.
• Thermoforming: Plastic sheets are heated and drawn into the desired shape.

These processes are ideal when high volumes with consistent quality are required. The end products are used in industries such as automotive engineering, the packaging industry or medical technology.

What is plastic machining?

Plastic machining, by contrast, describes the mechanical finishing or modification of already existing plastic parts. Precise tools and machines are used for this. Typical plastic machining methods are:

• Milling: Removal of material for shaping or adjustment.
• Turning: Use of rotating tools to machine cylindrical parts.
• Welding: Joining of plastic parts by heat or pressure.
• Bonding: Mechanical joining by special adhesives.
• Cutting and punching: Precise separation of workpieces.

These methods are ideal when prototypes or small series with individual adjustments are required.

Differences between plastic processing and plastic machining

The following table illustrates the most important differences:

Characteristic	Plastic processing	Plastic machining
Area of application	Series production	Prototypes and one-off parts
Methods	Injection moulding, extrusion, blow moulding	Milling, turning, welding
Material state	Raw material (e.g. granules)	Finished semi-finished product or component
Cost structure	Higher fixed costs, lower unit costs	Flexible costs, higher unit costs
Precision	Standardised products	Highly individual adjustment

Application in practice

The choice between plastic processing and plastic machining depends on several factors:

1. Production volume: Large series benefit from the efficiency of processing. Small series and individual parts can usually be produced more cost-effectively by machining.
2. Complexity: Highly complex designs often require finishing, while standardised parts can be processed directly.
3. Material properties: Some plastics are easier to machine than to process, particularly high-performance plastics.

Advantages and disadvantages of both methods

Plastic processing

Advantages:

• Efficient for large quantities.
• Consistent quality.
• Low unit costs at high volumes.

Disadvantages:

• High tooling costs.
• Limited flexibility.

Plastic machining

Advantages:

• High flexibility and precision.
• Lower initial investments.
• Suitable for individual adjustments.

Disadvantages:

• Higher costs per part.
• More time-consuming for large quantities.

FAQ

When should I choose plastic processing?

If you want to manufacture large quantities with standardised designs, plastic processing is the more economical choice.

Is plastic machining suitable for all plastics?

Not all plastics can be machined equally well. High-performance plastics often require specialised tools and methods.

How can both methods be combined?

A combination of both methods makes sense when parts are produced in series and then need to be individually adjusted. This frequently occurs in mechanical engineering or medical technology.

Which methods are more environmentally friendly?

Environmental friendliness depends on the energy efficiency and the amount of waste of the respective methods. Modern technologies in both areas attempt to optimise these aspects.

The choice between plastic processing and plastic machining should always be based on your specific requirements. Both methods have their strengths and are suitable for different areas of application. If you are unsure, advice from experts will help you find the optimal solution.