Processes

Vacuum Forming

Vacuum forming is a plastic thermoforming process that involves forming thermoplastic sheets into three-dimensional shapes through the application of heat and pressure. In general terms, vacuum forming refers to all sheet forming methods, including drape forming, which is one of the most popular. Basically during vacuum forming processes, plastic material is heated until it becomes pliable, and then it is placed over a mold and drawn in by a vacuum until it takes on the desired shape. Vacuum thermoforming is a great method for producing plastic parts that have sharp details and fit nicely to specific products.

During the vacuum forming process, a sheet of heated plastic material is placed over a male or female mold. The mold then moves towards the sheet and presses against it to create a seal. Next, the application of a vacuum draws out the air between the mold and the sheet so that the plastic conforms to the mold exactly. This is accomplished through venting holes in the mold that are joined to vacuum lines. The mold also has a water cooling system integrated into it that brings the temperature of the plastic to the set temperature needed. When the curing temperature is reached and the piece is formed, air blows back into the mold and separates the new part from the mold.

Vacuum forming produces plastic parts for various industries, such as the food, cosmetic, medical, electronics, entertainment, household products, toys, athletic equipment, appliance, automotive, office supplies and clothing industries. One of the most important industries that thermoforming serves, however, is packaging. Products like blister packs, inserts, trays and clamshells are used to house other products and are important for both preservation of the items they hold and the aesthetic designs they can provide. Consumer product manufacturers often use vacuum forming to produce plastic trays and glasses. Another interesting use for vacuum formed plastic is the creation of signs for gas stations and convenience stores.

The greatest advantage to vacuum forming is that it involves less parts and tooling than injection molding, and therefore is more cost-effective. It is an economical choice that can be used for small and medium production runs, with low cost tool modifications. There is great design flexibility available, from a variety of prototypes to custom made designs that can be used to cover almost any product. Most manufacturers also offer a wide variety of trim and other decoration options that can prove quite a visual advantage. Time of production is generally short, which frees up time to do more detail-oriented aspects of production. Sharp, precise detail is available for many products, which makes vacuum formed plastics an attractive alternative to other molding processes.

Advantages

• Economical for small to medium production runs

• Low tooling costs

• Quick startup

• High strength to weight ratio

• Efficient prototyping

• No need for painting; the color and texture are formed in