They are often used in conjunction with a plastic threaded fastener to distribute loads, prevent liquid leaks, relieve friction, isolate parts and prevent loosening in many different products, constructions and machinery.
Washers are most often made of a metal material or rubber, but plastic is sometimes used for its low cost, high temperature resistance and wide design range. Plastic washers are very popular plastic products. Like all washers, those made of plastic have many different design configurations. While all are round with a hole in the middle, some have a hole pattern or teeth on their outer perimeter. Other specifications include inner and outer diameter, hardness, thickness, temperature resistance, material type and their strength against chemicals, water, abrasion and other stresses.
They are usually small and can be fabricated out of nylon, which is most common, as well as polyester, polycarbonate, polyvinyl chloride, polypropylene and PTFE. Plastic washers are simple pieces of hardware, but they are important components in many different applications within the construction, plumbing, building, automotive and manufacturing industries. Washers come in many different colors and thicknesses.
All plastic washers are fabricated in high volumes by the stamping process. They are formed by a large, powerful mechanical press that is able to put out high cycles in a short time. Washers are made either to custom specifications or in standard sizes. Plastic stamping facilities that fabricate washers often have an extensive library of existing dies to choose from, so new configurations are less common. Since most washers are flat, they are made from large sheets of plastic.
Stamping presses have three main components: a frame, bolster plate and ram. The process is simple and takes seconds to produce hundreds of washers. First, the plastic sheet is tightly clamped down to the plate. Then, the metal die is attached to the ram. The ram, which is very heavy, then forces itself down on the plastic sheet with a great amount of force to cut out the washer design.
It can often perform up to 400 strokes a minute and produce hundreds of thousands of washers per day. This technique produces a large amount of extra plastic waste cut outs. However, these are almost always recyclable and used to fabricate more plastic sheets.