Find Out How Thermoforming Is Used In Manufacturing

One common manufacturing process that can be used to make a wide range of products such as toys, parts for cars and aircraft, electronic components, and packaging, involves using a thin sheet of heated plastic and forming it into various shapes. Known as thermoforming, there are several different techniques, but all result in producing items made from molded plastic.

There are multiple ways to thermoform plastic, but the general process is similar. A plastic sheet is held in place firmly as it’s heated to the point of pliability in an industrial oven, it is then stretched over a mold, and cooled down with fans until it is firm. While there are multiple types of plastic that can be used, HDPE or “high density polyethylene” is the most popular. The technique used depends on the type of plastic and size of the mold.

A vacuum thermoform process involves the use of a temperature-controlled vacuum unit in which both the mold and the sheet of plastic are placed, with the latter positioned above the former. The plastic is heated until soft, then the mold is raised to contact it, while air is suctioned out from underneath, creating an airtight fit which forms the desired shape.

Pressure forming implements compressed air which is released out of the top of the thermoform machine and exerts a force anywhere from 15 to 300 pounds per square inch onto the softened plastic. The amount of force required depends on the size of the form. The plastic is pushed into or around the molded shape from the air pressure.

A mechanical process uses a two-piece mold that has a top and bottom part. The plastic sheet is laid on top of the bottom, or negative half of the mold, and is then heated until soft, at which point the top or positive mold is lowered onto it, squeezing the plastic into the desired shape, and allowing air to escape through vents in the bottom piece.

Pressure diaphragm forming can be used to produce plastic parts by means of pressurized fluid and a vacuum. Twin sheet forming is useful for joining two plastic parts divided by a empty space, it works by melting the parts, and then attaching them to each other.

Manufacturers utilize this process because it has numerous advantages over other techniques, namely injection molding. The equipment required for injection molding costs considerably more, especially that used to produce large objects. It is also challenging to construct a suitable prototype for this method of molding, whereas with the thermoform method, this can be done simply and cost effectively.

Genevive B. Mata has over 20 years of professional sales experience, 10 of them directly in the plastic pallets and materials handling industry. On her spare time she works on applied-sustainability projects. If you are interested in industrial plastic pallet, she suggests you check out her friends www.ptm.com/global.

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