Thermoforming Process

In thermoforming, a plate-shaped plastic is heated uniformly before it is formed three-dimensionally by vacuum deep drawing or in a closed mould with a press.

This technique is ideal for giving plastic a permanent new shape. Thermoplastics can be heated to such an extent that they soften and can be formed. In order to ensure sufficient flexibility of the material before the forming process, either the complete component or parts of it are heated by hot air or infrared radiation.

Deep drawing with hot air

Leister air heaters and Leister hot air blowers are used to heat the material prior to forming processes. The wide range of services enables equipment selection best suited for the respective process.


In principle, the deburring of injection-molded plastic components is also classified as a forming process. The fine but unsightly burrs are heated to such an extent that they melt and reshape under the effect of surface tension. If several plastic parts or a sprue and a plastic part are connected to each other by narrow webs after the injection moulding or blow moulding process, they can be separated from each other by the targeted use of hot air.

Deep drawing with infrared

When deep drawing with infrared, the material is heated by infrared radiation. The fast reaction of the KRELUS infrared heaters from Leister allows the heaters to be switched off during non-productive times. This is particularly useful for sequential processes and results in considerable energy savings.

Plastics from the roll and plastic sheets are heated to produce moulded parts. Especially in the automotive industry, many molded parts, such as door panels and the classic parcel shelf are produced by deep drawing.

The KRELUS infrared heating sources from Leister are used for plastics from 1 mm thickness and up. This process itself is always the same:

  1. Insert plastic
  2. Heating
  3. Forming
  4. Cooling


The advantage of the infrared heating source is that it radiates heat precisely and efficiently.

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Save 50% Electricity when Thermoforming – is that Possible?