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Understanding thermoformable materials

The Mayku FormBox is compatible with a range of materials and thicknesses. For a full list of materials and thicknesses, please visit the Mayku Materials page.

The FormBox works really well with thermo-plastics (plastics that go soft when warm). Here’s the technical terms for these: 

  • Acrylonitrile Butadiene Styrene ABS (the stuff Lego is made from) 
  • Polystyrene PS (Product packaging) 
  • Polycarbonate PC (Drinks bottles) *
  • Polypropylene PP (Buckets, spades, chairs, everything!) 
  • Polyethylene (sheet and foamed sheet) 
  • PE (Insulating cases, bottles) 
  • Polyvinyl Chloride PVC (straws, plastic pipes) 
  • Acrylic PMMA (Light up signs) 

*Note: PC absorbs moisture that bubbles up when heated and requires pre-baking. You can dry out PC in an oven at around 90-120 degrees C for 6-12 hours (the longer the better), testing is required on a case by case basis.

How do I know when my sheet is ready?

The FormBox heating controls are set for the Mayku sheets and recommended temperature settings are on the material box as a guide.

However, there are no hard and fast rules as to how long this should take, so experiment with different times and temperatures to find what works best for your tool shape and environment as the ambient temperature can play a part when heating the material. Look for when the material just starts to bow and bring both trays down over your tool.

Wait 15 seconds after you've formed your object to allow it to cool down, then remove from the bed.

The video below shows what a Mayku sheet will look like when it’s ready to form: 

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Material size

Mayku sheets are pre-cut to fit the FormBox bed dimensions: 235mm x 235mm.

Material thickness

1.5mm sheets are the maximum thickness that can be used with the FormBox without running the risk of damaging the trays.

Materials thinner than 0.25mm could theoretically be used in theory, but they might not clamp tightly between the trays and require testing.

Environmental considerations

Be mindful of your environment when using the FormBox. Factors like open windows, drafts, and sunny days can influence and either slow down or speed up the heating process of the plastic. Thicker, high-temperature plastics tend to have higher success rates in warmer conditions.

Storage

Keep materials stored in the box out of direct sunlight for a longer life cycle.

Common thermoforming materials

When it comes to thermoforming, the choice of material is hugely important. It's essential to choose a material that is compatible with the desired application and the end product. Different materials have different properties and capabilities, so it’s helpful to understand these materials in order to make an informed decision.

Clear Sheets (PETG - Polyethylene Terephthalate Glycol)

Clear Sheets (PETG - polyethylene terephthalate glycol) is a rigid material with good impact resistance and great thermal characteristics, allowing it to cool efficiently without warping. It has superior chemical resistance compared to many other transparent plastics, making it a top choice for food-safe packaging, molds and transparent prototypes. PETG is recyclable and considered food safe, making it an eco-friendly and safe material for food contact applications.

  • Forming temperature: 160°C
  • Casting temperature: If being used for casting, molds made from clear sheets will start deforming at around 60°C. We recommend keeping your hot casting materials below 50°C to avoid damaging your molds. 
  • Shelf life: As a raw material, PETG in pellet or sheet form can last several years under proper storage conditions. Once processed into a product, its lifespan will vary based on the use-case and environment.
  • Protective film: Our Clear sheets come with a protective film. Make sure to remove before use.
    Storage: Store in a cool, dry place away from direct sunlight.

Why should you choose Clear sheets for your product?

  • Easy to fabricate
  • Fast cycle times, particularly at thinner gauges
  • Food safe
  • Semi-rigid
  • Good impact resistance
  • Optically clear
  • Good chemical resistance
  • Smooth and clean surface finish

Learn more: Mayku FormBox Clear Sheets

Form Sheets (HIPS - High Impact Polystyrene)

Form Sheets (HIPS - High Impact Polystyrene) is a lightweight and durable thermoplastic. It is produced by combining styrene monomer with a rubber-like polymer called polybutadiene, resulting in a hard and rigid plastic. Form sheets are easy to process, relatively inexpensive, and can be coloured and decorated with silk-screen printing and spray paint. HIPS offers a combination of stiffness, impact strength, and dimensional stability, making it suitable for applications that require these qualities.

  • Forming temperature: 160°C
  • Shelf life: Form Sheets can last several years when stored properly.
  • Storage: Form Sheets should be kept in a cool, dry place. It is also sensitive to UV light, which can cause discoloration or brittleness, so keeping it away from sunlight is crucial.*

These are some of the advantages of Form Sheets:

  • Highly durable and resistant to impact
  • Easily machinable and formable
  • High temperature and chemical resistance
  • Good dimensional stability
  • High stiffness and strength
  • Good electrical insulation
  • Low cost

Learn more: Mayku FormBox Form Sheets

Flex Sheet (EVA - Ethylene-Vinyl Acetate)

Flex Sheets (ethylene-vinyl acetate) is a versatile material known for its flexibility, strength, and shock absorption capabilities. It's easy to process and recycle, making it an environmentally friendly choice.

It is flexible and resistant to many materials, such as resins, making it ideal for creating reusable molds as it’s easy to de-mold. It is non-toxic and can withstand temperatures ranging from -35 °C to 60 °C.

  • Forming temperature: 130°C
  • Shelf life: EVA, especially in its raw form, can retain its properties for several years under ideal storage conditions.
  • Storage: Store Flex Sheets in a cool, dry place away from direct sunlight. 

Here are some reasons why you may considering choosing Flex sheets for your project:

  • Shock absorbent capabilities
  • Insulating and waterproofing properties
  • Easy to process and recycle
  • Excellent flexibility
  • Good strength
  • Tear resistant
  • UV resistance

Learn more: Mayku FormBox Flex Sheets

Using third-party materials

If you are using a third-party material, we recommend contacting the material manufacturer or seller before use to confirm:

  • Working temperature: Determine the working temperature of the material for casting and the heating time, as this can vary between sheets.
  • Safety concerns: Verify if the material releases harmful fumes when it melts. For example, do not use PVC, as it can release chlorine gas if it burns. If in doubt, ensure you position the FormBox in a well-ventilated area.

While we can’t guarantee the quality of third-party materials, it’s always worth a try.