Thermoforming is the wider manufacturing process where a sheet of plastic is heated until pliable and then formed over or into a tool. Vacuum forming is one of the most widely used types of thermoforming, using vacuum pressure to draw the heated sheet over the mould.

The terms thin gauge, thick gauge and heavy gauge are used to describe the thickness of the plastic sheet being formed.

Thin gauge thermoforming usually refers to thinner roll-fed plastic material used for products such as food packaging, medical packaging, retail blister packs and disposable trays. Heavy gauge thermoforming or heavy gauge vacuum forming generally refers to thicker individual plastic sheets used to produce more robust and longer-lasting components.

In strict industry usage, heavy gauge thermoforming is often associated with sheet above around 3mm. However, some manufacturers use the term thick gauge more broadly for cut-sheet forming from approximately 1.5mm upwards, depending on the material, part size and application.

For this reason, the most important question is not simply whether a part is “heavy gauge”, but what the part needs to do in use. Strength, rigidity, impact resistance, finish, chemical resistance, UV stability, fire performance and repeatability may all influence the material and thickness selected.

A wide range of thermoplastic materials can be used in heavy gauge and thick sheet vacuum forming. The best material depends on the required appearance, strength, temperature resistance, impact resistance, chemical resistance and operating environment.

Common materials include:

• ABS for tough, impact-resistant components and housings
• HIPS for cost-effective formed parts and display applications
• PETG for clarity, toughness and ease of fabrication
• Acrylic for high-quality visual applications and display components
• Polycarbonate for impact-resistant parts where strength is important
• HDPE for durable, chemical-resistant components
• Polypropylene for lightweight, chemical-resistant applications

At Wrights Plastics, material choice is part of the manufacturing discussion. We can advise on suitable sheet materials depending on the part design, application, finish and expected production volume.

Thin gauge and heavy gauge thermoforming are related processes, but they are usually used for very different types of product.

For buyers looking for engineered plastic components, heavy gauge vacuum forming is usually the more relevant process. It allows larger, stronger and more functional parts to be produced without the tooling investment normally associated with injection moulding.

Vacuum forming and pressure forming are both types of thermoforming, but they use different levels of forming force.

In vacuum forming, a heated plastic sheet is drawn over a tool using vacuum pressure. This is a highly versatile process and is widely used for industrial covers, guards, trays, housings, panels and formed plastic components.

Pressure forming uses additional air pressure to push the heated plastic sheet more tightly against the mould. This can achieve sharper detail, deeper texture and more defined features, making it useful where a moulded part needs a more injection-moulded appearance.

For many industrial plastic parts, vacuum forming offers the right balance of performance, tooling cost, speed and flexibility. It is particularly effective where the part needs to be functional, durable and repeatable, but does not require the higher-cost tooling associated with injection moulding.

Injection moulding is an excellent process for very high-volume plastic parts, but it usually requires expensive tooling. For larger components, prototypes, short runs or medium-volume production, vacuum forming can be a more practical and cost-effective alternative.

Heavy gauge vacuum forming can offer several advantages:

• Lower tooling costs compared with injection moulding
• Faster development from design to sample part
• Suitable for larger plastic components
• Good flexibility for design changes
• Practical for prototypes, short runs and repeat production
• Wide choice of thermoplastic materials
• Ability to combine forming with CNC trimming, fabrication and assembly

This makes vacuum forming especially useful for companies that need robust plastic components but do not want to commit to high-cost injection mould tooling at the early stage of a project.

To quote accurately for a heavy gauge vacuum forming project, it helps to provide as much information as possible about the part, its application and expected production volume.

Useful information includes:

• A drawing, CAD file, sample part or sketch
• Approximate dimensions
• Required material, if known
• Required sheet thickness, if known
• Colour and finish requirements
• Annual or batch quantities
• Whether tooling already exists
• Any fixing points, holes, slots or cut-outs
• Whether CNC trimming, fabrication or assembly is required
• The environment the part will be used in
• Any impact, chemical, UV, fire or cleaning requirements

If you are unsure which material or thickness is required, Wrights Plastics can help review the application and advise on the most suitable manufacturing route.

Wrights Plastics provides industrial vacuum forming and thermoforming services from our UK manufacturing facility in West Bromwich. We work with customers that need practical formed plastic components for sectors including automotive, medical, transport, highways, infrastructure, retail display and industrial equipment.

Our in-house capabilities include vacuum forming, tooling support, CNC trimming, drilling, routing, plastic fabrication, assembly and despatch. This allows us to support projects from early prototypes and samples through to repeat production.

If you need a heavy gauge or thick sheet vacuum formed component, speak to Wrights Plastics about your part design, material requirements and production volumes. We can help assess whether vacuum forming is the right process and advise on tooling, finishing and manufacturing options.