1. Sheet extrusion.
Extrusion is understood as the continuous production of a semi-finished product, tube or plastic film. One possible technology to be used in this context is sheet extrusion. Material width can be in excess of 2 m with thicknesses ranging from 0.5 to 15 mm and unlimited length.
Solid sheet extrusion units consist of at least one extruder and one sheet extrusion die. They are followed by the polishing stack, in general comprising 3 calenders, calibrating and cooling the sheet with their surfaces or calender nips. Behind this the roller conveyor and the draw-off rolls for air cooling are located. The sheet is finally cut and stored.
2. Vacuum termoforming.
Thermoforming is a manufacturing process for thermoplastic sheet or film. The sheet or film is heated between infrared, natural gas, or other heaters to its forming temperature. Then it is stretched over or into a temperature-controlled, single-surface mold. Cast or machined aluminum is the most common mold material, although epoxy and wood tooling are sometime used for low volume production. The sheet is held against the mold surface unit until cooled. The formed part is then trimmed from the sheet. The trimmed material is usually reground, mixed with virgin plastic, and reprocessed into usable sheet.
