is performed to remove burrs, smoothen edges, eliminate forge scales or improve the surface quality of objects. The items are placed in a rotating drum or a vibrating container and is either circulated through the machine “plain” or with the addition of a grinding agent. The deburring process can be performed wet (most common) or dry. During wet tumbling water or oil is used with added chemicals and grinding agents, which can consist of aluminium oxide, silicon carbide, steel, etc.
The surface treatment is often the last stage in the manufacturing process, which generally has been preceded by some form of mechanical work where oil has been used for lubrication or cooling. Oil may also be used as corrosion protection during interim storage of the items. Alkaline and acidic parts cleaning, or degreasing with a solvent (trichloroethylene) is performed to remove oils, grease etc., from the item’s surface before the final stage of surface treatment (see list above). For the same reason steeping is employed to remove forge scale, rolling skin, rust and other types of oxidation layers. Steeping is commonly accomplished by submerging the item in one or more acids, but also complex-forming alkaline salts and steeping pastes may be used. (Even electrolyte steeping may occur.)
Delrin is a particular manufacturer’s trade name for Polyoxymethylene (POM). This is a plastic that is often used as a substitute for metal items. The primary characteristics are low weight, low friction, durability and it can be used in temperatures up to 90˚ centigrade. Certain hinge pins in the Industrilas product inventory are made of Delrin/POM.