Vacuum thermoforming, also called vacuum forming, is a version of thermoforming where sheets of plastic are heated to a soft state. It is then stretched onto or into a single-surface mold, and then held against the mold by applying a vacuum force between the mold and the warm, malleable plastic. Then the plastic is allowed to cool. Once released from the vacuum, the plastic is an exact representation of the mold's shape. Finally, it is trimmed to create the final part.
Vacuum forming is usually, but not always, restricted to forming plastic parts that are shallow in depth. Thin-gauge thermoforming is common in packaging, as well as other uses. A thin sheet can be formed into rigid cavities, bubble packs, clam shells, or even the lid of a drinking cup. In Thick gauge thermoforming a thick sheet can formed into permanent objects such as fenders, skylight, trim, and protective covers.
Relatively deep parts can be formed if the form-able sheet is mechanically or pneumatically stretched prior to bringing it in contact with the mold surface and before vacuum is applied.
Vacuum forming is also appropriate for transparent materials such as acrylic or polycarbonate. We currently make several different sized skylights from smoke colored polycarbonate, and even have a large diameter lens we make from acrylic.
There are many advantages to consider when thinking about vacuum thermoforming. Because of the cost and time required creating the molds or tooling of other plastics forming processes, many other processes such as injection molding can be cost prohibitive. For smaller runs of parts custom thermoforming can be a viable alternative. This is in part due to the fact that we can make molds from materials such as wood, fiberglass, and aluminum. Thin gauge thermoforming can provide product protection at a lower cost than comparable packaging. Thermoforming products are typically packed and shipped nested, this saves on freight and storage costs.