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The guy running the Okuma next to me said my finish passes looked like I was in a hurry, so I dropped my feed from 12 to 8
He was right, I was pushing it to get parts out the door and you could see the chatter in the 7075 blocks under the shop light. Ran 40 parts with the slower finish pass and my surface finish came in at 32 Ra instead of the 55 the print called for, no scrapped pieces since. What feeds and speeds are you guys running on 7075 for a good finish without burning through inserts?
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robin89615d ago
That moment when the guy next to you catches something you missed is weirdly a gift, even if it stings a little at first. Dropping from 12 to 8 on the finish pass and getting 32 Ra instead of 55 is a huge win, and zero scrapped parts over 40 pieces says it all. I run 7075 a fair amount and I usually back way off on the finish pass too, like .005 depth, around 6 to 8 ipm, and bump the rpm up instead of pushing feed, since 7075 hates being rushed on the last cut. Chatter shows up fast in that stuff, especially in thin walls or long reaches, so sometimes I'll take two light spring passes instead of one and it cleans up nice. Inserts last way longer when you let the spindle do the work instead of the feed, in my experience. Sounds like you already found the sweet spot, and honestly listening to the old guy next to you was the cheapest tooling upgrade you'll ever get.
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