26
Finally got a stubborn 316 stainless part to hold size after three scrapped pieces
Kept getting about 0.0015" of spring after roughing, even with a light finish pass. Tried slowing the feed and using more coolant, no luck. On the fourth piece, I left 0.030" for the finish pass but ran it in two steps: 0.020" off, then a final 0.010" cut at the same speed. For some reason, that second light kiss held the dimension perfectly. It added maybe two minutes to the cycle. Has anyone else found a specific multi-pass trick for holding tight tolerances on gummy materials?
3 comments
Log in to join the discussion
Log In3 Comments
the_keith2mo ago
My buddy Mark at the old shop had the same fight with some 304. He started leaving a fat 0.040" for finish and taking it in three decreasing passes, like 0.020", then 0.015", then a final 0.005". It was the only way the part would stop moving on him. Sometimes the material just needs to relax in stages.
4
kai_west2mo agoMost Upvoted
Man, that's the truth. My own version of that was trying to hog out a deep pocket in some 316. Left what I thought was a good finish pass, and the whole side wall just leaned in like it got shy. Had to walk it back in baby steps just like your buddy. Felt less like machining and more like convincing the part to please, for the love of god, just stay put.
4