I was sure that fancy new tool coating was just marketing hype

Our shop in Akron got a sample of some new titanium aluminum nitride coated end mills last month. I looked at the price, almost double our usual ones, and figured it was just a gimmick. My boss said to run a test on a tough 4140 steel job we do a lot. I set up two machines, one with the new coated tool, one with our regular. After 3 hours, the regular tool was done, chipped and dull. The coated one? It ran for another full shift, about 8 hours total, and the finish was still sharp. The rep said it reduced heat and friction, and I guess he wasn't lying. It convinced me to push for buying a small batch for our harder materials. Has anyone else run a side-by-side test on tool coatings and been surprised by the results?

3 comments

3 Comments

the_julia3mo ago

Yeah, that's a huge difference in run time. Did you happen to check the temperature of the chips or the part itself between the two tools? I'm curious how much cooler it actually ran, since that's where a lot of the wear comes from.

the_felix3mo ago

Did you use coolant or just air?

vals381mo ago

Tried both ways on my last project with some tough aluminum. Air just blew chips everywhere and the part got too hot to touch after a few minutes. Switched to a basic coolant setup and it was night and day, the part stayed cool and the finish was way better. That's exactly what @the_julia is getting at with tool wear, heat is the real killer. I got probably triple the life out of my endmill before it started to dull.