In the world of machining, and even manufacturing in general, titanium seems to be held in the highest of regards. NASA uses it, so there has to be some validity to that. We see and hear it all the time from customers and those interested in buying a Tormach.
“So, can this thing cut titanium?”
Now, that’s a valid question if you’re planning on cutting titanium, but more often than not, people use titanium as a litmus test for a machine. The thought is often, ‘If it can cut titanium, it can cut anything.’
Steel vs. Titanium
Titanium is a hard metal, but the best steels are generally stronger than titanium alloys. The big difference in strength comes in at extreme temperatures and pliability.
Steel can only handle temperatures up to around 2,700° F, whereas titanium can get up to 3,300° F. At subzero temperatures, steel has a tendency to shatter when titanium does not.
When it comes to pliability, both metals are quite hard, but titanium has the ability to flex or bow repeatedly. Steel will often rupture when flexed too far.
The challenge most people have with titanium is that it is incredibly unforgiving when it comes to tool wear, feeds and speeds, etc. When adjusting and tweaking your machining, steel gives a much larger window for producing a quality part, while titanium requires a delicate (even finessed) hand to make adjustments for a better surface finish or tool wear.
Titanium is also quite expensive. For the same size stock, a bar of titanium is roughly nine times the price of a bar of stainless steel.
Where Titanium Pays Off
Titanium has two large advantages over its metal brethren: weight-strength ratio and it’s biologically inert.
Materials for the medical industry can be complicated – they have to be strong, consistent, adaptable, and not interfere with the human immune system. Steel implants are prone to causing the development of serious medical conditions, while titanium is generally accepted by the human immune system because it is non-poisonous and biologically inert.
The real payoff with titanium is the weight-to-strength ratio. Generally speaking, steel is about 5% stronger than titanium, but that same bit of titanium will be 40% lighter. This is where the real justification for such a pricey metal is justified.
What It All Comes Down To
Titanium is an incredibly useful material that really helps make many industries safer and more efficient, but not without a price – literally, the price.
But, titanium is a terrible litmus test for the abilities of a CNC machine. The adjustments needed to make this metal shine (both figuratively and literally) is incredibly important and nuanced, as is the tooling selection process, which can make things frustrating after spending a pile of money on just the raw material. Can a Tormach mill cut titanium? Absolutely, but what’s more impressive is the finish you can achieve in stainless at such a low price tag.
Just for good measure, here is a video of Tormach Brand Ambassador, John Saunders, cutting titanium on the PCNC 440.