Switched to diamond tooling on aluminum and ate through stock way too fast

I've been running 6061 on a Haas VF-2 for about 3 years now and always used carbide end mills with good results. Last month I tried a $120 Kennametal diamond coated end mill because I heard it would outlast carbide and give a better finish. Turns out it chipped on the second part and left a terrible surface finish on the rest of the job. Has anyone else had a bad experience running diamond tooling on non-abrasive materials or is it just my feeds and speeds being off?

2 comments

2 Comments

milalewis7d ago

Oh man, diamond tooling on aluminum is a trap a lot of guys fall into lmao. Diamond end mills really need high abrasive materials like graphite or composites to work right, so on 6061 the edge just crumbles instead of cutting clean. Your feeds and speeds probably were fine, it's just the wrong tool for the job on non-ferrous stuff honestly.

danielowens7d ago

Read an article a while back that said diamond tooling reacts chemically with aluminum at high cutting temps, which just speeds up the wear even more. So it's not just the edge crumbling, it's basically dissolving into the chip at the contact point. Makes sense why uncoated carbide or even a nice polished carbide works way better for 6061.