In order to achieve the quality and accuracy required in micro-milling while meeting economic constraints, the entire manufacturing chain must be optimized and synchronized. Vendors of CNC machines, cutting tools, holders, clamping tools and quality control equipment are all required to provide the right solution at a competitive cost.

Following is a checklist of the major issues that should be addressed in a micro-milling environment:

1) Cutters, Holders and Spindles
Small-sized cutters are the enablers of micro-milling. Depending on job size, they can be as small as 0.1mm, and will probably get even smaller in the future. Availability and cost of cutters must be considered before committing to a micro-milling project.
While using small cutters, high-speed spindles are critical. A spindle with 10,000 rpm and 0.1mm cutters means a cutting feed (Vc) of only 3.3 m/min—this is much too slow!
With rpm levels at 20,000-150,000, a fully balanced combination of spindle and shrink holders, with zero runout, is a must; otherwise, surface quality will be compromised and tool life will be dramatically shortened.

2) Fixtures, Clamping Systems and Manufacturing Processes
In most cases, the production of micro-milling parts should be done with a single setup. For example, combining EDM and milling would likely result in unacceptable mismatches and marks.

3) Machine and Shop Floor
It goes without saying that the machine must be consistently accurate and sensitive to the fourth decimal digits (mm controller).

Micro-milling can make good use of five-axis milling. The ability to tilt a tool away from the material enables using shorter tools. However, since continuous five-axis milling is currently less accurate than three-axis milling, machine specifications and actual performance must be carefully validated when using continuous five-axis for micro-milling.

Machine environment must have a controlled temperature (software compensation might not be enough) and free from vibrations. If the machine is not properly isolated, even a heavy truck that passes outside the facility might generate enough of a vibration to leave its marks on the surface.

4) Milling Technology
Depending on part geometry, micro-milling might require special machining strategies that go beyond simply scaling everything down. In many cases, for example, conventional milling (and not climb milling) would be the preferred milling strategy.