Ti-6Al-4V is the structural alloy of implants, instruments and anything where strength per gram matters. It is also a material that fights the cutter in three separate ways. At micro scale, where the tool is fragile and the walls are thin, each of them gets worse.
Titanium conducts heat poorly, so the heat of cutting does not leave with the chip the way it does in steel or aluminium. It stays in a small zone at the cutting edge, and the tool pays for it. Speeds that would be conservative in steel burn a titanium cutter, and on a micro tool the margin between cutting and failing is already small.
Every cutting edge has a radius, and below a certain chip thickness the tool stops cutting and starts rubbing. In titanium, rubbing generates heat with nowhere to go and work-hardens the surface the next pass has to cut. So the feed per tooth has a floor, and a lighter cut is not the safe choice it looks like — which is the whole problem with scaling a conventional recipe down to a micro cutter.
Titanium is roughly half as stiff as steel. A thin wall or a slender feature pushes away from the cutter and springs back after it passes, so the finished wall is thicker than the path the tool took. That is predictable enough to compensate for, but only if the cutting strategy, the support of the feature and the measurement are planned together.
Hot titanium welds onto the cutting edge and builds up, changing the edge geometry mid-cut and tearing the surface when it lets go. Sharp tools, the right coating and a steady supply of coolant to the edge are what stop it. Built-up edge is also why a titanium surface finish is decided by tool condition more than by the toolpath.
Ti-6Al-4V (Grade 5) is the general-purpose alloy. Its extra-low-interstitial version (Grade 23, supplied to specifications such as ASTM F136) is the one implants are usually made from. Both machine the same way; the difference is in the certified chemistry of the bar, which is why material certificates travel with the stock.
Biocompatible · lightweight
Ti-6Al-4V (Grade 5/23) is the most commonly implanted structural metal alloy. Its combination of specific strength, osseointegration capability, and MRI compatibility makes it the default for orthopedic and spinal implants.
These are standards the material grade is tested or supplied to by its manufacturer. They describe the resin or the bar stock, not a finished part — qualifying a part for patient contact is the device owner’s decision, made under their own quality system.
Have a part in Titanium? Send the drawing with the grade and the dimensions that matter, or talk it through with Marve first.