Why Stainless Steel Tests Every Machinist

Stainless is honest work. It doesn't cut easy, it work-hardens fast, and it eats tools if you're not paying attention. At AOOM Technology, we CNC process stainless steel daily — 304, 316L, 17-4PH — and we've learned the hard way what works and what doesn't.

The Heat Problem

Stainless holds heat at the cutting edge. Unlike aluminum that pulls heat away, stainless lets it build up. That's why we run high-pressure coolant through the spindle — 70 bar minimum. It blasts chips out and keeps the cutting zone below critical temperatures.

Without that, tool life drops by half. A client came to us after their previous supplier was burning through inserts every 50 parts. We dialed in coolant pressure and increased feed rate slightly. Tool life jumped to 200 parts per edge. Same geometry, same material, better parameters.

Tooling Choices Matter

We use carbide end mills with AlCrN coatings for stainless. The coating handles the thermal load better than TiAlN in high-temp alloys. For finishing, we run sharp-edge geometry with light DOC to avoid work hardening the surface layer.

A medical client needed 316L surgical components with a burr-free edge finish. We programmed a spring pass on the finishing contour — eliminated the burr without secondary hand work.

Grades We Run Most Often

304 for general industrial parts. 316L for medical and marine — better corrosion resistance. 17-4PH for aerospace — it heat-treats to high strength while staying machinable in the annealed state. Each grade needs different speeds and different tool engagement angles.

Inspection on Stainless Parts

Surface finish matters more with stainless because post-polishing is expensive. We hold Ra .8μm standard and can hit Ra .2μm with dedicated finishing passes. CMM and surface profilometer readings go in every inspection report.

Send your CAD files to chen@aoomtech.com for a quote within 24 hours.