Exploring Thermoforming: A Versatile Manufacturing Technique
Explore how Thermoforming works, what it’s used for, and how you can bring industrial-level vacuum forming to your business.
Thermoforming is a powerful technique for manufacturing detailed high-accuracy moulds, packaging solutions, product casings, and more. Industries across the board — from consumer goods to automotive — put this technology to good use.
Industrial-grade thermoforming machines have traditionally been prohibitively large and costly, limiting SMEs’ access to the technology. Now, desktop-sized pressure-forming and vacuum-forming systems, like Mayku, are changing the thermoforming landscape.
In this article, we’ll explore how thermoforming works, what it’s used for, and how you can bring industrial-level pressure and vacuum forming to your business.
What is Thermoforming?
Thermoforming is a family of industrial manufacturing techniques. In all thermoforming methods, a plastic sheet is heated until it becomes pliable. The sheet is then shaped and contoured with the help of a mould into a final product.
Whether it uses pressure or a vacuum, the thermoforming process is relatively fast and simple, enabling high productivity and low lead times. The basic process consists of six steps:
- Clamping: The thermoforming machine’s operator places a plastic sheet into the material frame and clamps it firmly in place.
- Heating: The machine applies an appropriate amount of heat to the plastic until it turns soft and pliable.
- Forming: The operator lowers the softened material sheet onto a mould and contours it tightly in place using strong pressure or vacuum suction.
- Cooling: After completely forming the part, the operator must allow the plastic sheet to cool to avoid deformation. Fans or water mist may occasionally be used to cool the part faster.
- Releasing: Once the part has cooled completely, the operator raises the material frame and removes the mould and part from the machine.
- Trimming: The operator trims excess plastic off the final part and carries out potential post-processing steps, such as sanding, painting, or coating.
Thermoforming: Pressure Forming vs. Vacuum Forming
As we mentioned, thermoforming is an umbrella term covering multiple different technologies. The most common of them are pressure and vacuum forming.
Pressure forming, as its name implies, uses high pressure to force the heated plastic sheet in place over the mould. Pressure-forming machines, such as Mayku Multiplier, can produce plastic pieces with a very high detail quality, comparable to injection moulding. Due to the intense pressure, pressure forming can create complex geometries and intricate details.
Vacuum forming relies on powerful vacuum pumps to suction the plastic sheet over the mould. The vacuum generally isn’t as strong as air pressure, which means the technology can’t produce as detailed parts or work with as thick plastic sheets as pressure forming. However, vacuum-forming machines — like Mayku Formbox — are often more affordable and still an excellent option for producing high-quality packaging materials and equipment components.
Another difference between pressure and vacuum forming lies in the types of moulds they use. Thermoforming processes can be carried out using two types of moulds:
- Positive moulds, also called “male” moulds, feature convex and protruding shapes. With these moulds, the side of the plastic sheet in contact with the mould forms the final part’s inner dimensions. Positive moulds are more common with vacuum forming, where intricate detail isn’t as important.
- Negative moulds, or “female” moulds, are concave. The plastic sheet’s contact surface forms the resulting part’s outer dimensions with this type of mould. Negative moulds are typical for pressure forming, as they allow the technology to make the most out of its high detail quality.
Advantages and Limitations of Thermoforming
But why should your manufacturing SME care about thermoforming — whether pressure or vacuum? Both technologies bring companies notable benefits, the most significant of which include:
- Affordable small-batch production: Thermoforming is much more affordable and cost-effective for producing small volumes (~300 units annually) of products and components than, for example, injection moulding.
- Short lead times: Thermoforming can offer up to two times faster turnaround times than injection moulding. You can enhance lead times even more with an in-house thermoforming machine, like Mayku Multiplier pressure former, and a 3D printer for mould production.
- Mould material range: Thermoforming moulds can be manufactured out of a great variety of materials, from 3D-printed plastics and resins to simple wood. This flexibility allows you to quickly produce suitable moulds without large overheads or lead times.
- Repeatability: Thermoforming is highly unlikely to damage suitably chosen moulds, which leads to high dimensional accuracy and repeatability between parts.
- Food-safe and biocompatible parts: Manufacturers can use thermoforming to produce food- and medical-grade parts and containers with materials such as PETg.
Pressure forming, in particular, also boasts the added benefits of extreme detail level and precise part tolerance (with negative moulds). Pressure forming can also handle thicker materials than vacuum forming, up to 5mm in thickness.
Yet, every technology has its limitations. Vacuum forming has geometric limitations, which can, fortunately, be resolved by using pressure forming.
All thermoforming technologies, however, suffer from low cost efficiency with large production batches. Injection moulding becomes more affordable when we start talking about thousands of parts.
Thermoforming Uses and Applications
Thermoforming is a versatile manufacturing technique and many industries have adopted it for various purposes. In general, the main difference between pressure and vacuum-forming applications is the desired level of detail. Pressure forming shines where high detail and tolerances are required, while vacuum forming is ideal for cost-effectively producing less detailed pieces.
That said, the two technologies are used in very similar ways. Let’s look at the most common thermoforming applications.
Automotive manufacturing uses large-scale thermoforming (both pressure and vacuum) to manufacture entire body components, from bumpers to seat frames. Smaller machines are used to produce interior parts, such as dashboard panels, and prototypes for testing purposes.
Many general industrial manufacturers use vacuum forming to produce tight-fitting, secure container insets for sensitive parts. Pressure forming, on the other hand, is very popular for intricate products that must withstand exposure to outdoor weather, such as acrylic advertising signs
If you’ve ever bought a product with form-fitting packaging, it was likely produced with thermoforming. Vacuum forming is the go-to choice for consumer goods packaging, from personal grooming and make-up products to the finest electronics and smart devices. Pressure forming is often used for more detailed products, like toys and sports equipment.
Since it’s compatible with food-grade plastics, thermoforming is commonly employed to produce packages for food products. Most packaging trays, egg cartons, fruit containers, and other such thin packages are made with thermoforming.
Vacuum forming is widely used to produce packaging for medical appliances, while pressure forming is a common method for the appliances themselves. It’s all thanks to thermoforming’s compatibility with antimicrobial and bio-safe materials. The technologies produce everything from simple tablet packages to body panels for high-end MRI machines.
Desktop Vacuum Forming
Traditionally, thermoforming has been relegated to large organisations due to price and space constraints. Huge industrial thermoforming machines can cost hundreds of thousands of pounds and require so much floor space that SMEs could only dream of owning one.
In recent years, this pattern has changed. Floor-standing and later desktop-sized pressure and vacuum-forming machines have democratised the technology.
Costing between a few hundred to a few thousand pounds, these affordable and compact devices have made thermoforming accessible to even small one-person manufacturing workshops.
One example of such a brand is Mayku. This London-based company manufactures pressure and vacuum-forming devices that allow any business to bring the technology into their own facilities.
Mayku Multiplier is the world’s first desktop pressure former. This industrially-oriented machine generates 60 psi of pressure — exerting more than 5 tonnes of force — to quickly and accurately form prototypes, packaging, moulds, jigs and fixtures, and end-use components with a maximum diameter of 400 mm in less than five minutes.
The high pressure results in very accurate, industrial-grade detail quality. Combined with engineering and medical-grade plastic sheets, the Multiplier is a good fit for a wide range of applications.
Mayku Formbox is a compact yet powerful small-scale vacuum-forming unit. With a maximum heating power of 340°C, it’s capable of forming 200 x 200 mm moulds, containers, and prototypes within two minutes. In addition to organizations such as Nike and NASA, Formbox is a popular device among educators.
Bring the Vacuum to Your Business
Desktop thermoforming machine manufacturers, like Mayku and others, are levelling the playing field between small and large companies. Once reserved for large-scale industrial organizations, today practically any operation can start pressure and vacuum forming parts in-house.
The advantages of the technology are undeniable. Even a small crafts business can quickly and affordably produce secure, unique packaging trays to keep fine handcrafted products intact during shipping.
Yet, the versatility of thermoforming makes it equally suitable for medium-sized — or even large — businesses. The cost-savings and fast turnaround times enable quick prototyping, reducing time-to-market. Meanwhile, in-house low-volume production can help organizations reduce overheads in outsourcing.
Thermoforming also works well with other desktop manufacturing methods. It’s possible to 3D print intricate, durable moulds using materials such as PLA. These components can be processed further with desktop CNC machines to ensure extreme dimensional accuracy.
Thermoforming opens up an entire world of new business opportunities. Thanks to compact and affordable desktop units, this manufacturing technology is now more accessible than ever.
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