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Should we rough set with finishing tools or stick to roughers?
I been running a job on a Doosan mill this week cutting 4140 steel. Normally I use a 1/2 inch rougher to hog out material then swap to a finishing endmill. But I got lazy on a rush job and tried using a 3/8 four flute AlTiN coated finishing tool for roughing at 2500 RPM and 30 IPM. It actually worked pretty good and saved a tool change. Now I'm wondering if I'm overthinking my setups. Anyone else skip roughers sometimes or am I asking for a broken tool?
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angela_harris7d ago
My buddy had this happen on a Doosan too actually. He ran a rush job in 4140 years back and figured he'd just use a finishing endmill for roughing to save time. First pass was fine, second pass the tool snapped and shot a chunk of carbide across the shop. That's when he learned that those AlTiN coatings are great but the geometry on finishers just ain't made for hogging. If you're taking light passes it might work short term, but the second you hit a hard spot or a chip recut you're toast. I'd stick with the rougher for anything over a light cleanup pass, that tool change is cheaper than a broken part and a scrap bin.
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joel_clark377d agoMost Upvoted
Buddy of mine did the same thing on a Haas, cost him a whole facemill.
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wade8717d ago
Yeah man, that's exactly the kind of lesson you only learn once. I've done the same thing on a Mazak, grabbed a finisher for a quick roughing pass in 304ss thinking I'd save 30 seconds on a tool change. Worked fine for like 3 parts, then on the fourth I heard that nasty crack and watched the insert fly. @angela_harris is dead right about the geometry, finishers have that sharp edge and light chip load design, they just cant handle the vibration and heat from hogging. I keep a dedicated rougher loaded now for anything over 0.050" doc, even on a rush job. The time you lose switching tools is nothing compared to scrapping a part halfway through.
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