Titanium CNC Machining

I've been machining titanium for 18 years. Here's what I can tell you that the textbooks don't emphasise enough: titanium doesn't machine like stainless steel, it doesn't machine like aluminium, and anyone who tells you "just run the same feeds and speeds" is selling you tooling.

Heat is the enemy. Titanium retains heat at the cutting zone. Unlike steel, where the chip carries away most of the heat, titanium keeps it in the tool. This is why you see so much edge breakdown on titanium jobs. We run through-spindle coolant at 70 bar minimum, and we use CBN tooling for finishing passes. It costs more per insert, but it cuts down overall cycle time because you're not stopping to change tools every 15 minutes.

Work hardening. Same problem as stainless, but worse. If a tool starts to dull and rubs instead of shearing, the surface hardens instantly. The next cutter hits that hardened layer and either deflects (out of tolerance) or chips (dead tool). We maintain constant chip load through adaptive toolpath strategies. This is especially critical in thin-wall aerospace parts where deflection causes both tolerance and work hardening issues simultaneously.

Spring-back. Titanium has a lower modulus of elasticity than steel — about half. This means thin sections deflect more under cutting pressure and spring back when the tool passes. We account for this in CAM by over-cutting spring-back areas and using rough plus finish passes with light finishing depths.

Our approach: For titanium, we never quote standard cycle times based on material removal rates. We quote based on tool life optimisation — finding the feeds and speeds that maximise the number of good parts per tool, not the fastest possible cycle. This gives our customers consistent quality and predictable delivery dates.