HOME  > Plastic Molding Tutorial  > #133 Vacuum Molding Method, Compressed Air Molding Method
Plastic Molding Tutorial

#133 Vacuum Molding Method, Compressed Air Molding Method

Category : Molding Technology
December 7, 2012

The vacuum molding method is a method used for molding articles such as egg packages, pudding cups, packaging containers, etc. that are made of thin plastic sheets.

In the vacuum molding method, melting of raw material pellets such as in extrusion molding is not made, but a plastic plate formed in advance in the shape of a sheet is deformed by vacuum suction on to a heated mold (see the figure).

図

The mold is provided with several holes for vacuum suction. In order to support the deformation of the plastic sheet, a plug is also sometimes lowered to press down the sheet.
On the other hand, the compressed air molding is a molding method in which the plastic sheet is deformed by compressed air.

The edges of the items molded using these methods are cut by a press in a succeeding step or else, they are cut by scissors if such parts are small in quantity.

The plastics that can be molded in this manner are:

-Polystyrene foam
-Hard PVC
-Polypropylene
-Polyethylene terephthalate
-Methyl ester methacrylate (acrylic plastic), etc.

It is only necessary to prepare either the male mold or the female mold.

The materials used for the mold are mainly nonferrous metals such as an aluminum alloy, duralumin, zinc alloy, brass, etc.

MISUMI USA eCatalog