Material sheet thickness below .060″ is generally regarded as thin gauge. Common applications of thin-gauge thermoforming consist of rigid or semi-rigged packaging trays designed to contain anything from food to component parts used on factory assembly lines. Thin gauge parts are often designed to be disposable or recyclable.
Heavy gauge parts are typically made for permanent end-use on durable goods or for reusable items like material handling equipment and industrial dunnage. We have the capacity to utilize thermoplastic sheet ranging from .060″ up to one half inch thick. Some notable permanent-use parts Asheville Thermoform Plastics has produced include desk panels, housings large and small for electronic components and mechanical devices used in telecommunications, industry and medicine; control consoles for heavy transportation equipment; interior cosmetic surfaces in large appliances such as refrigerators; panels, light covers and ductwork for the aerospace, automotive, recreational vehicle and marine industries; and formed upholstery substrates for medical and marine seating applications.
What is Thermoforming?
At its most basic, “thermoforming” is the use of any method that applies heat to material in order to make it pliable, and then applies force to shape the object or material as desired. Thermoforming plastic, then, is the use of any method that applies heat to plastic material in order to allow the shape of the plastic object or material to be altered. Some common plastic thermoforming techniques and terms are explained below.
- By far the most prevalent use of thermoforming in industry is Vacuum Forming. In fact, the term Vacuum Forming is often used interchangeably with Thermoforming. Developed in the 1950s, vacuum forming is a manufacturing process in which a flat sheet of plastic is heated to its softening temperature, then pulled over or into, a mold. Vacuum (negative pressure) is applied to remove trapped air and force the plastic sheet against the contours of the mold. Once cooled, the vacuum formed part retains the shape of the mold or form. The part is then separated from the surrounding sheet material, which is recycled for reuse, and finish-trimmed.
Pressure Thermoforming applies positive air pressure to force the heated plastic into the cavity of a negative (female) mold, or onto the exterior of a positive (male) mold.
Matched Mold Forming
- Matched mold forming uses matching positive and negative molds that are brought together with the heated plastic sheet sandwiched in between them, forcing it to assume their shape. A variation using a male mold that is not closely matched to the female in size or shape to push the material into the cavity is known as “plug assist” forming.
- Line bending involves heating portions of a thermoplastic sheet material using localized heat such as a strip heater until it becomes soft and pliable, then bending it to any angle, using a jig or a former, or simply bending the thermoplastic sheet by hand and then holding it until it has cooled.
- Similar to bubble forming and billow forming; these variations allow the material to sag under the force of gravity forming a bubble or dome shape. No molds are used; only gravity and sometimes air pressure.
- Plastic sheet is heated to its pliable state, then literally “draped” over a mold and manually shaped. May be done in an oven.