Is It Really That Hard to Machine Titanium?

In short, yes.

Machining titanium is often billed as the pinnacle of a machine tool’s capabilities, but really it’s less about the machine itself and more about the machinist. That doesn’t mean that tooling and your machine aren’t important, but like so many things in the world of machining, there are a million ways to make the cuts you need.

Arguably, that’s what makes machining titanium such a challenge.

Titanium is hard. Well, grade 1 titanium – meaning pure titanium – is actually a somewhat soft metal, but the most common alloy, grade 5, is hard.

What’s more, titanium is also a gummy metal to cut.

So, you’re dealing with the challenges of both harder steels and softer metals like aluminum. That means proper feeds and speeds combined with chip clearing is key to cutting titanium.

Another challenge when cutting titanium is the fact that the material doesn’t dissipate heat through the part, so heat gathers at the point of cutting. This can cause work hardening as you’re cutting or even deformation and chipping of your cutter.

With all of this being said, titanium is just a finicky metal to cut. But there are ways to make it easier.

Tooling for Cutting Titanium

The hardest part about picking tooling is the fact that Ti can be both gummy and hard. Typically with gummy materials you look to using cutters with fewer flutes. Conversely, when cutting hard materials (like stainless), having multiple fluted end mills is ideal so you can engage the cutter properly at desired feed rates.

Using tooling with positive cutting geometries can really help with the wear and heat challenges that titanium can create. To that end, using cutters with rounded inserts or a tool nose radius can help as well.

Coolant

Use it! Lots of it!

Coolant is important to keep things cool, literally. Titanium has a tendency to heat up at the point of cutting, so hitting it with coolant at the source can really help. Also, because Ti has a tendency to be gummy, getting those chips out is vital to properly cutting this picky material.

Cut Titanium When It’s Soft

The fact that titanium gets harder with heat can be used to your advantage too. You can get Ti in a number of different states. Finding the softest state of your chosen alloy can help make the process easier, and then use heat to harden things up after the fact.