Methods And Manners Of Plastic Fabrication

2 July 2015
 Categories: , Blog

Plastic fabrication is an integral part of the production and merchandising of goods. From plastic figurines to hardened plastic tool kits, oyster-shell packaging to airplane components, plastic fabrication forms the framework upon which much of our modern world is built.

Plastic fabrication machines and methods vary by tool, company, or product need, but in general there are six fabrication methods used to produce plastic products: dip molding, blow molding, vacuum forming, injection molding, plastic extruding, and rotational molding.

Perhaps the most basic method, dip molding is used to create either fitted products (latex gloves, for instance) or to coat existing products in plastic, like coating a wire. For fitted products, molds are coated with nonstick chemicals, then dipped into a vat of resin. For coated products, the process is the same, though instead of preparing the surface with nonstick materials, it is instead prepared to hold the plastic in place. The resin-coated molds are then dipped into cooling vats, and if necessary, the process is repeated.

In blow molding, a tube-like parison of plastic resin is placed in a mold, then injected with air. This injection causes it to puff out and match the shape of the mold.

Vacuum forming is used to produce faceplates or other semi-flat products. The products are formed when a plastic sheet is heated until pliable, then vacuum compressed onto a mold.

The injection molding process is able to produce complex shapes, including three-dimensional or solid plastic products. Injection machinery typically consists of a hopper, an extruding barrel, and a die. The hopper is loaded with plastic pellets, which the barrel melts before injecting them into the die.

Similar to injection molding, the process for plastic extruding involves a hopper feeding plastic pellets through an extruding barrel, where they are melted and sent through a die. Unlike injection molding, however, the die is open, allowing the plastic resin to be squeezed through into a particular shape and then cut into specific lengths.

Though slower than other processes, rotational molding allows for strong, structurally complex plastic pieces. Plastic resin is placed in a sealed mold, which is then rotated in a gyroscope until the resin has coated the entirety of the mold cavity.

As with other cast products, the process by which the finished product is fabricated can affect its strength and tolerance. The tolerance level in particular varies depending on the fabrication method. Generally, a product that is cooled (either in water or in a specific cooling process) holds a tighter tolerance, as do methods involving less complex shapes.

To learn more, contact a company like Industrial Plastics & Paints