Dip Coaters
Dip coaters take finished metal products and submerge them in molten plastic which forms a protective coating. The process is inexpensive, simple and quick. Wire hangers, fencing, grating, electric wire, tool handles, exercise equipment, gas pump handles, playground equipment and dishwasher baskets are all commonly dip coated with plastics. The most common choices for coating are PVC (polyvinyl carbonate), which provides a more flexible and less rigid coating, and plastisol, a vinyl based mixture of resin and plasticizer. The coating serves many purposes. It may act as thermal or electrical insulation for electric wires, chords and products like jumper cables, add handle covers to increase gripping ability and provide an attractive finish to many different products.
The dip coating process is simple and only takes three short steps. First, the finished metal product is cleaned and coated with chromate or phosphate, which increases the molten plastic's adhesion. Next, the product is dunked into the molten plastic and left there for a certain amount of time, referred to as the dwell time. The longer it is left in the plastic, the thicker the coating will be. Finally, the product is slowly removed from the plastic at a constant speed and heat treated. Dip coating is almost totally automated because of its simplicity. Large batches of products are dipped at the same time, and the process takes up to two minutes at the most.