Mass finishing is an industrial process that allows for the finishing of large numbers of pieces simultaneously in batch or continuous processing. This reduces the need for hand finishing of components and can cut down on expenses and increase efficiency. Providers of mass finishing services may offer a range of options for clients. Large companies may also set up their own facilities for in-house finishing, which can be less expensive in the long run than contracting these services out to a third party.
In mass finishing, large numbers of rough parts can be smoothed, descaled, polished, and subjected to other processes. A classic example can be seen with plastic toys, which are poured into molds and tumbled out into mass finishing equipment. When the toys first emerge from the molds, they may have snags and burrs from the edges of the molds, along with a rough appearance. By the time they reach the end of the line, they are smooth to the touch and polished.
Two primary mass finishing techniques are available, vibratory and tumble finishing. In both cases, materials are finished through rubbing and friction, either against each other or a medium like beads, pastes, or gels. The best choice can depend on the materials and the volume. Mass finishing equipment can be run on a number of different settings to produce varying levels of vibration or tumbling for different types of materials.
In dry mass finishing, the process is entirely dry, and may include the use of powders and beads. Wet mass finishing wets the materials, and may involve the use of finishing supplies like chemicals to lift scales and other deposits of unwanted materials. These chemicals can be tumbled or vibrated with the materials to ensure even circulation across all surfaces. This may be necessary with metalworking, where metals can acquire dulled finishes during processing and need to be cleaned up for the market.
Batch finishing allows for the handling of a set amount of materials in a single load. It can be suitable for small to medium scale production. Continuous flow processing allows a facility to process materials on an assembly line or conveyor for constant finishing. Products enter the line unfinished, move through a series of steps, and appear fully finished and ready for assembly or packaging for sale. Continuous processing is most suitable for large volumes of standardized products that are in constant production.