Swarf refers to the leftover turning chips of metal that have been through a metalworking process such as grinding, drilling, turning, or milling. It is analogous to the sawdust and wood shavings that result from woodworking. Swarf, however, is more dangerous, necessitating a more rigorous removal process to ensure the safety of workers and the environment. Since it is not easily degraded and often contains sharp edges, it can create cuts and splinters when not handled properly.
During grinding, milling, and some drilling processes, swarf is often generated within the machine tool itself. These processes will generally apply coolants and additional fluids, known as cutting fluids, both to control the heat generated by the machines and to remove the swarf that is created. Drilling processes, which create holes within a metal, are often designed so that newly created swarf is pushed up through the hole being drilled. This strategy proves to be efficient in most cases, but occasionally with deeper holes the turnings will aggregate and become too densely packed, necessitating cutting fluids to break up the particles.
Cutting fluids, coolants, and other liquids used during these metalworking processes can create a sludgy mixture of the metal filings that can make safe disposal difficult. To assist in this process, there are many chip wringers and centrifuges that are designed to remove the liquid from the metal swarf. Depending on the process, filings can be dried down so that they only contain around 2% of the original liquid volume.
In turning processes, the filings are often generated in a dry environment, forming powders and fine shavings that need disposal. Liquids are not always favorable in this case, and instead magnets and magnetic wands are often used to safely collect the byproducts. Most of these magnetic products are designed for optimal safety of the workers and guard against any inadvertent contact between the filings and the skin.
Once the swarf has been dried and collected, it is sometimes made finer by a chip breaker, which breaks down larger and sharper pieces into smaller shavings that are easier to handle. Chip breakers, shredders, and crushers will also minimize the total volume of the metal byproducts, making it easier to dispose of them efficiently. The uniform shavings are then compressed into bricks or blocks with compressing machines known as briquetters. These dense bricks can be more easily disposed of, and they will often be recycled for use in other metalworking processes.