What is Micro-Machining

Understanding Micro-Machining

What is Micro-Machining

From a less technical standpoint, micro-machining, also written as micromachining, can generally be used in reference to the process of machining features that are too small to be machined by conventional machining processes. However, looking at the process from a technical perspective that considers the literal meaning of micro, which means the millionth of a unit, in this case, the meter, the definition takes on a new form. In this context, micro-machining involves the use of subtractive micro-tools and techniques to fabricate features with at least one dimension ranging from 1 micrometer (µm) to 999 µm. This means the diameter of the tools’ cutting edges measures 1 µm to 999 µm. 

However, the International Academy for Production Engineering Research (CIRP), which helps standardize technical terminology, notes that the micro/macro border is sometimes set at 500 µm. (This figure is, however, not cast in stone, as it varies based on the machining method used.) In that case, the range of micromachining is said to primarily vary between 1 µm and 500 µm. To further prevent ambiguity, the CIRP defines three criteria that subtractive processes, especially mechanical processes, must obey to be considered micro-machining methods. These include:

1. The processes must use a tool whose diameter ranges between 1 µm and 500 µm; the sizes of the features must also fall within this range

2. The undeformed/uncut chip thickness (a measure of the tool penetration depth or the amount of material the tool removes) must be the same as the workpiece grain size (the estimated average diameter of a grain of a metal or alloy)

3. The undeformed chip thickness and the workpiece grain size must be in the nanoscale range to a few micrometers in length and comparable to the tool edge radius 

Schematic Representation of Undeformed Chip Thickness (Source: CIRP)