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Rant: I spent 8 months fighting with tool paths on a 3 axis mill before a buddy showed me how to rough with a bigger stepover
I used to baby my roughing passes, like .02 stepovers thinking I was saving the machine. Last year a machinist in Detroit watched me set up a job and just laughed. He told me to bump it to .06 on the first pass and let the coolant do the work. Cut my cycle time by 40% on that part and the finish was still fine. Anybody else get stuck in a habit that made zero sense after someone called them out?
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ray6135h ago
Had a very similar moment watching my buddy rough out a part on a worn out old Bridgeport. He was taking cuts that made me wince. I asked him if he was trying to break the thing. He just said "Son, that machine's been taking that since before you were born." Made me feel a little bit foolish for treating mine like it was made of glass.
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coleman.hannah9h ago
Oh man, the "baby roughing" habit is REAL. I got stuck in that same trap for like a year and a half on a little bench top mill I used to run. My buddy calls me out after watching me take these tiny little .015 passes on a 2 inch piece of 6061 and goes "are you cutting butter or carving a sculpture?" Haha. He showed me the same thing, bump it up to .05 or .06 and let the chip evacuation do the heavy lifting. It felt so wrong at first, like I was abusing the tooling. But after I saw how much faster the job went and the part still came out good, I felt like an idiot for not trying it sooner. I convinced myself that small passes meant better accuracy, but really I was just wasting time and burning up end mills with all that rubbing (you know, instead of actually cutting).
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You ever stop to think maybe those little passes are saving your tooling in the long run though? I mean, sure you can hog off material faster, but pushing a cheap end mill that hard on a bench top mill just wears it out twice as quick. I've had jobs where I'd rather take my time and not have to swap inserts or carbide every ten minutes. And accuracy wise, I've had parts come out with chatter marks from pushing too deep, especially on thinner walls. So yeah maybe I'm just slow and careful, but I'll take a longer run over a ruined part any day.
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