Workholding with fusible alloys

Some components are too fragile, too awkwardly shaped or too highly finished for workholding by conventional clamping. One alternative to the specially made fixture – always slow and expensive to produce – is to use a bismuth‐based low‐melting‐point alloy as the work‐holding medium. Alloys specialist Mining and Chemical Products says that with melting points as low as 47°C and the unique property of expanding on solidification, fusible alloys can often provide a quick and cost‐efficient means of turning difficult work‐pieces into something much easier to hold for machining and handling. The low melting temperatures eliminate risks of heat damage to work‐pieces, while the non‐shrinking characteristic ensures extremely solid support even during the most arduous machining operations. According to MCP, bismuth alloys are also highly economic to use. They can be melted down and used again repeatedly. This is not true of other work‐holding media. Moreover, since many of them contract on solidification they cannot provide the firm and all‐embracing support that is almost always needed.