What is the Difference Between High-Pressure Forming and Injection Moulding?


High-pressure forming and injection moulding are both types of plastic forming. While injection moulding is best suited for small, high-volume parts, high-pressure forming offers advantages for smaller runs of larger parts – with reduced set-up costs, faster time-to-market and more control over details like surface finish. To help you decide which option is best for you, here are the differences in more detail…


For injection moulding, plastic pellets are melted before being injected into a mould, where pressure is applied, and the parts left to cool before being ejected. The process is highly repeatable, so it is great for large production runs, which also offset the higher set-up and tooling costs involved.

High-pressure forming involves heating a thermoplastic sheet until it is malleable. Positive pressure is then applied above the heated sheet, pressing the material into a mould to create the desired shape. Once it is cool, secondary processes such as trimming and cutting out can take place.


Pressure forming allows customers to get the look of an injection moulded part without having the high volumes required to justify set-up costs. It allows texture to be added to the tooling that gives different surface finishes to the completed part. You also achieve less ‘wall thinning’ during manufacture compared to vacuum forming, meaning that thinner materials can be used and product weight reduced.

The injection moulding process can create a lot of stress on the plastic, with heating to high temperatures and fast cooling time. When processed correctly, pressure forming can maximise the properties of the plastic/resin used and avoid stress on the material before it is even in place in a product.

High-pressure forming also avoids tool marks and fault lines, which are often seen on injected moulded parts.

Turnaround Time

One of the biggest advantages of high-pressure forming over injection moulding is the time-to-market. The time between prototyping and production can be as little as 2 or 3 weeks, whereas tooling for injection moulding can take several months to produce.

Volume and Cost

As mentioned above, set-up costs are much higher for injection moulding. The tooling required for the process is made from more expensive materials, like hardened steel. The design of the tooling is usually much more intricate and naturally results in a more intense, lengthy and costly stage compared to pressure forming. It is vital to get this stage in the production process correct, as any defects in the mould itself could result in wasteful and very costly mistakes.

If you have very large production volumes, this initial outlay will be offset and justifiable. However, for customers with smaller volume requirements, high-pressure forming offers the detail of injection moulding in a more cost-effective way, with cost advantages that increase with the size of the part being produced.

High-Pressure Forming From Cox Wokingham

Cox Wokingham has the skills and experience to push the limits of high-pressure forming as well as the technology and equipment to maximise its capabilities, resulting in numerous benefits for the customer, as detailed above. Using the GEISS T10 Pressure Former machine, we can satisfy the demands of projects across a wide range of industries, extending design parameters and excelling against our competitors. For more information about the services we offer, please visit our website or contact a member of our team.



Our approach is that every challenge is an opportunity to experiment, to innovate and to further our skills to the benefit of our customers.

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COX’s expertise in the planning and production of prototype pieces is your shortcut to the right solution. Right on specification. Right on practicality and performance. And right on budget.

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COX offers a comprehensive range of thermoforming services, including vacuum forming, press forming and line bending.

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As well as having the skills and experience to push the limits of High Pressure Forming, COX also offers the technology in the shape of its huge GEISS T10 Pressure Former machine.

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Through a wide range of high-quality Fabrication services, we have the facility to add extra value for our customers.

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Years of experience and application have given us an unrivalled reputation in advising on the properties and performance potential of a huge range of materials.

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Our design, toolmaking and manufacturing services are second to none. From solving complex CNC programming issues to creating intricate jigs and specialist fixtures, the first step of a successful project is speaking to COX.

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Our CNC machining capabilities are high on our list of specialisms. Whatever your requirements, we have the expertise and technology to develop the solution that’s exactly right for you.

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We offer our customers a range of assembly and sub-assembly services, including painting, screening and shielding.

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We can take care of all of your world-wide distribution requirements and export documentation.