The CNC machining process that shapes parts into flat or complex forms is called milling. It is carried out on a CNC milling machine, a machine with a built-in computerised numerical control centre that guarantees precision machining.
Before looking at how stainless steel CNC machining works, it’s worth explaining how milling is structured: a cutting tool mounted on a spindle rotates while the motorised axes move at the same time. Qualified companies know which cutters to use for each material.
Take steel, for example: its machinability varies according to several factors, such as alloying elements, heat treatment and the manufacturing process used. Various problems can arise during machining, such as burrs and built-up edge (with mild steel) or chipping (with hard steel).
Stainless steel CNC machining: how to do it
Stainless steel covers two main groups: austenitic and duplex steels, and ferritic and martensitic steels. Machining this material is not easy: common issues include burrs, poor surface finish, chipping of the cutting edges due to thermal cracking, built-up edge and notch wear.
For roughing, it is best to choose high cutting speeds (vc = 150–250 m/min) and machine dry to reduce thermal cracking. For finishing, we recommend using cutting fluid or mist coolant/minimum quantity lubrication, while avoiding too low a feed, which can increase insert wear.