Thermoforming is a manufacturing process offering many advantages for small, medium and large series production.
The design and production of the tools required for its implementation are simpler and faster than for other technologies such as injection for example, which makes it very competitive, particularly in the production of small series.
Carried out by vacuum or under pressure, thermoforming allows the production of complex shapes, high thicknesses, even in large dimensions, with controlled tooling costs.
The principle of thermoforming
Thermoforming is based on the principle of glass transition of thermoplastic materials: they are heated above the glass transition temperature [Tg] and once this step is completed, they are transformed into a rubbery state which will allow them to be given the desired shape. To optimise production quality, ovens (drying, post-forming annealing) are used to prepare the thermoplastics for the various stages of thermoforming.
The stages of thermoforming
- A mould is positioned inside the machine box on a tray that can move vertically inside the box.
- A thermoplastic sheet is clamped on a frame (reducible format) which also ensures the sealing of the box.
- The material is heated to the forming temperature (infrared sensor) by means of electric infrared panels (halogen, quartz or ceramics).
- Once the optimum temperature has been reached (depending on the thickness of the sheet or the type of material), the heating panels are removed and the softened sheet is then pre-stretched by air injection (bubbling).
- The mould moves to the upper position to shape the part: a vacuum pump then sucks in the air so that the sheet fits the mould perfectly, with mechanical assistance if necessary.
- The part is then cooled while remaining on the mould until it can be removed (demoulding) without adhesion or deformation.
With the MECAFORM range, MECANUMERIC offers high-speed industrial thermoforming equipment which has proved its worth in fields as varied as the automotive industry, aeronautics, POS, signage, handling, etc. They are perfectly adapted to the production of complex parts with high forming depths such as seat parts for aeronautics.