Vent: Tried a 5/8 carbide end mill on aluminum and got a bird's nest from hell

I was running a job in Cleveland last Tuesday. Simple pocket on 6061. Grabbed a 5/8 three-flute carbide end mill. Figured I could push the feed rate a little. Big mistake. About 10 minutes in the chips just stopped breaking. Wound up into this massive tangled mess around the holder. Took me 20 minutes to cut it off with snips. Part got thrown off by the vibration too. Scrapped the whole thing. Learned my lesson on chip evacuation. You guys run dedicated chip breakers for aluminum or just stick to two-flute?

2 comments

2 Comments

spencer_ross6d ago

Did you at least get a cool video of the bird's nest before cutting it off? I had a similar thing happen with a 3/8 rougher last month and the mess was so bad it looked like a failed art project. I usually stick to two-flute for aluminum, especially on deep pockets, because three-flute just packs up on me when I get greedy with the feed. Honestly, my go to now is just a dedicated chip breaker or a high helix two-flute, and I slow down the feed if I start seeing strings. I learned that lesson the hard way too, nothing like 20 minutes of snipping to remind you to respect the material.

rose_hart316d ago

Actually two-flute isn't always the best for deep pockets in aluminum. Three-flute can work fine if you run a high helix variable flute endmill. The key is the geometry, not just the flute count. Most guys I know including myself run OSG or Garr three-flute roughers for aluminum deep pocketing and they clear chips better than a standard two-flute ever will. Sounds like you might have been running a general purpose three-flute instead of one actually designed for aluminum.