The food and beverage, sporting goods, electronics, medical, appliance, automotive, cosmetics, telecommunications and commercial goods industries all use plastic forming processes that heat a sheet of plastic material and shape it through a mold.
The most common products made from plastic forming processes are plastic packaging. The three different types include blister packs, clamshells and plastic trays, all of which are used to protect, transport and display many different commercial products for sale. Forming offers low tooling costs, quick start-up and cost efficiency for small to medium production runs.
Many different plastics are formed, including polyester (PET), used for packaging, high density polyethylene (HDPE), which makes bottles and bags, polyvinyl chloride (PVC), used for food wrap, vegetable oil bottles and blister packaging, polypropylene (PP) food containers and caps, high grades of polystyrene (PS), which are best for products like disposable plastic silverware, CD cases and cartons. Other materials that may be used in plastic forming services include acrylonitrile butadiene styrene (ABS), acrylics, polycarbonate and Kydex, which is a PVC-based thermoplastic.
Of the many different plastic forming processes vacuum forming is one of the most popular options. The popularity of vacuum forming, or thermoforming, is in part due to its long history as well as its relative simplicity. This process works by first heating a plastic sheet of uniform thickness. The material is heated until it reaches the desired level of softness and pliability.
Depending on the specific properties and thickness of the plastic polymer, the heating time and temperature will vary. The heated sheet is then transferred to the forming station where it is enclosed between two mating molds. The air between the molds is removed using a vacuum pump which forces the plastic sheet to press against the mold.
The sheet is allowed to dry and cure while pressed against the mold. Once it has dried, the molded plastic is removed and trimmed if necessary. This is the simplest method of vacuum forming, but there are many other more complex vacuum forming processes, including pressure forming and twin sheet thermoforming.
Pressure forming is similar to the vacuum forming process except it also uses compressed air to press the plastic sheet more tightly against the mold which allows for more detailed products. Twin sheet thermoforming also uses the same process as basic vacuum forming except the process is done for two separate sheets of plastic at the same time. Once the two sheets have been molded they are welded together to create a hollow product. The process chosen depends largely on the intended use and essential properties of the finished product.