Micromachining popularly refers to any machining at a scale small enough that the small scale itself presents added difficulties to the machine shop. Technically, the term is generally misapplied. In technical terms, “micromachining” refers to machining of features at scales around one micron. Very little production machining involves scales that small. A more technically accurate term would be “mesomachining,” which refers to machining of features on the scale of 10 microns or 100 microns. However, on this site and in the text that follows, “micromachining” is used in the more popular, less precise sense of referring to any machining work that is particularly small.
Micromachining is used to machine medical implants, electronics components and even tiny features of particularly small molds. The work is performed on machining centers, EDM machines and very precise turn/mill machines such as CNC Swiss-type lathes.
One of the difficulties of micromachining has to do with the added delicacy with which both the tools and the machined workpieces have to be treated. A tiny tool or part can easily be damaged just by dropping it on a workbench or letting it strike another part or tool. For shops accustomed to machining standard-size parts, the gentle treatment can require new processes with separate disciplines for micromachining work.
Tool and workpiece setup also impose additional challenges. Workholding has to locate the tiny part very precisely for the machined features to have any chance of locating accurately. Ditto for the tool—toolsetting has to be particularly precise as well. Inspection presents similar challenges. Determining whether the tiny part has been machined correctly may be impossible using gages or CMMs that only measure at macro scales. Determining when to change tools can be equally difficult, because the sound of the cut can no longer be heard and tool is too small for any wear lands to be seen by eye. A microscope becomes a common and essential workbench accessory for the shop engaged in micromachining.