High-speed industrial plastic thermoforming technology
Industrial thermoforming technology is a manufacturing method that offers many advantages for small, medium and large production runs.
The design and production of the tooling required for its use are simpler and quicker than for other technologies such as injection moulding. This makes the technique highly competitive, particularly when it comes to small production runs.
The principle of plastic thermoforming
The thermoforming process brings about the glass transition of thermoplastic materials by heating them above the glass transition temperature [Tg] of the materials to be thermoformed. Once this stage has been completed, the materials go into a rubbery state, enabling the desired shape to be obtained to within a millimetre.
To optimise production quality, ovens are used (drying, post-forming annealing) to prepare the thermoplastics for the various stages of thermoforming.
Thermoforming can be carried out in a vacuum or under pressure, enabling the production of objects with complex shapes and great thicknesses, even in large dimensions and volumes, with controlled tooling costs.
The stages of thermoforming
There are several techniques for choosing the right equipment, but generally speaking, the process for producing an object using an industrial thermoforming machine is as follows:
- A mould is positioned inside the machine's casing on a plate that can move vertically.
- A thermoplastic sheet is clamped onto a frame (reducible format) which also ensures that the chamber is watertight.
- The material is heated by infrared electric panels (halogen, quartz or ceramic) to forming temperature (infrared sensor).
- Once the optimum temperature has been reached (which varies according to the thickness of the sheet or the type of material), the heating panels are removed and the softened sheet is pre-stretched by air injection (bubbling).
- The mould is moved to the upper position to shape the part: a vacuum pump then draws in the air so that the sheet fits perfectly into the mould, possibly with mechanical assistance.
- The part is then cooled while still in the mould, until it can be removed (demoulding) without adhesion or deformation.
Thermoforming meets the needs of industrial companies in a wide range of applications
There are many applications for thermoforming techniques in various sectors of industry requiring the manufacture of moulds and parts with the most perfect surface possible, such as :
- Aeronautics, with the manufacture of aircraft seats (plastic parts, synthetic resins and foams),
- Signage, point-of-sale advertising and communication are all very plastic-intensive sectors, with the thermoforming of outdoor signs.
- Packaging, in the food industry for forming large volumes of plastic containers used to package foodstuffs.
- Land transport, with the moulding and manufacture of seats for the rail industry (trains, trams, metros, etc.) and the automotive industry.
CNC industrial equipment for thermoforming operations and finish machining
With the MECAFORM range :
MECANUMERIC, fabricant d’outils industriels, propose des machines CNC de thermoformage à haute cadence.
Il s’agit de presses semi-automatiques d’usinage par le vide de matières plastiques thermoplastiques dont le réglage de la puissance de chaque élément rayonnant peut être réalisé de façon individuelle.
Plastic machining technologies, complementary to industrial thermoforming
The 5-axis CNC milling machine with a fixed table, moving gantry, 4 Cartesian axes and 2 polar axes is optimised for the finishing machining of large plastic parts produced by the thermoforming process. Plastic, foam or resin materials can be used to create the finished products.
5-axis milling machine for creating models and moulds or 5-axis machining of thermoformed or rotomoulded shaped parts. Raw materials such as aluminium, wood and its derivatives, brass and alloys can be machined with this type of CNC machine.
NORMAPROFIL WINNER series: designed for 5-axis machining of large precision 3D parts. A wide range of electrospindles are available for machining plastics, composites and aluminium alloys.