Vacuum forming machines use thermoplastic sheets, which means that the plastics soften when heated. They include polystyrene, acrylonitrile  styrene (ABS), polyethyene  glycol (PETG) and acrylic. The sheet thickness is generally limited to under an eighth of an inch.  vacuum forming machine, also called vacuum-forming , is a fast, simple way to make parts from plastic. It is used at all skill levels, from hobbyists to large manufacturing companies. Parts made by this process include packaging materials, trays, toys, and auto dashboards

  Vacuum forming machine molds can be made of many common materials, such as plastic, wood or metal, as long as they're stable and heat-resistant. Typical mold sizes range from a few inches to more than a foot. The size of the plastic sheet dictates the maximum mold size, and the mold designer must not create a mold so large or tall that the stretched sheet can't fit around it. If you're molding small items, it makes sense to arrange several small molds on the molding table to make the most of every plastic sheet. The molds must also have strategically placed vent holes so the air can be drawn out evenly, avoiding bubbles.