Thermoforming is a method of the heating a plastic sheet and shaping it with air pressure or vacuum on a mold. After the sheet is formed it is cooled to obtain the definite form. In vacuum forming a negative pressure is used in the molding step.      The process may replace parts in fiberglass, wood, metal or injected plastic, since it has some advantages regarding to manufacturing cost, depending on the technical features and on the quantity of parts to be produced      Usually, Thermoforming is cost effective in the following cases: when producing disposable products with thin walls, when producing blister/clamshell packing and when producing parts of relatively large area where the injection process becomes expensive.