Shoutout to the old timer who showed me a better way to clean up arcs

I was struggling for like 2 years with arc cleanup in my CAM software. Always had to go in and manually adjust the lead in and lead out, or the tool would leave this little divot at the start of the cut. Finally had this guy named Dave, been running CNC since the 80s, walk over and watch me for a minute. He just pointed at the screen and said "try blending the entry angle into the arc, not the straight line." Changed the approach from 90 degrees to something like 120, and it cleaned up perfect on the first try. No more sanding time afterwards. Has anyone else had a moment like that where a simple adjustment changed everything about how you run a program?

2 comments

2 Comments

phoenix_adams601d ago

Yeah the 90 degree entry thing gets a lot of people. I had the same problem on a 3 axis mill with aluminum. Switched to a tangential arc entry about 3 times the tool diameter and it stopped leaving that little bump every time. Also check your lead out radius, if its too tight you get a mark on the exit too. Dave's tip about blending into the arc instead of the straight line is solid. Once you figure out that angle thing it saves so much cleanup work.

derek991d agoMost Upvoted

Man that little bump is the worst, I've been there more times than I care to count. It's one of those things that looks so minor but drives you absolutely nuts when you're trying to get a clean finish. The tangential arc trick really is a lifesaver once you dial it in right, saved me from having to hand sand so many parts back when I was learning. And you're dead on about the exit mark too, I had a job where I was chasing that thing for three days before I realized my lead out was just a hair too tight. Stuff like this is why I always tell new guys to spend the extra time on their entry and exit moves, it pays off big time in the end.