Surface roughness Ra is a measurement of the deviation of a surface from a mean height. The lower Ra measurement, the higher grade surface quality. At the same time, the more machining process will be required. Generally speaking, a workpiece completed by CNC lathe or milling could reach a surface roughness between Ra 0.8-3.2.

Based on the capability of our CNC machining service, we are capable of manufacturing aluminum alloy parts with suface roughness between Ra 0.1-0.2 where is required on an ABS system for optimized piston movement. Normally, we supply the machined parts within Ra0.8-3.2. For your reference, the higher grade surface roughness, the more expensive production cost. 

* micro-meters(um) = 0.001mm

** micro-inches(u”) = 0.0254um