Vacuum Forming

• What is vacuum forming and what is it used for?

  A heated sheet of polymer is forced down over the mould by air pressure due to a temporary vacuum being created beneath the airtight seal around the sheet of polymer.

  Its used to make items such as yoghurt pots and fast-food containers
• What is the process of vacuum forming?

  • A specially designed mould is placed on the platen of the vacuum-form machine and lowered
  • A sheet of thermoforming polymer is clamped into the machine and then heated
  • When softened, compressed air is blown into the chamber, which stretches the material upwards
  • The platen is raised and a vacuum pump removes air from the chamber, pulling the pliable sheet onto the mould
  • The material is cooled and removed from the mould
• What factors do you need to consider when using vacuum forming?

  • Corners and edges need to be rounded to prevent webbing and holes
  • No undercuts are allowed in the design, otherwise you will not be able to remove the material from the mould
  • Vent holes are required to prevent the material from failing to follow the shape of the mould
  • The sides of the mould will need to be tapered (5 degrees) to allow the formed product to be removed from the mould