topic Re: 3D machining, Smoothing, I,J output, Limited block processing speed, etc.. H in Fusion Manufacture Forum

3D machining, Smoothing, I,J output, Limited block processing speed, etc.. Help?

cmleschak — Wed, 27 Jun 2018 14:22:16 GMT

We have an old CNC Knee mill (Supermax YCM-40 / Dynapath Delta 20). I set it up a few years ago to drip feed from a laptop so we can program on Fusion since the conversational is slow and cumbersome, plus has its obvious limitations. Anyhow, sometimes I make some intricate parts on this old machine and run 3D profiles. The problem we run into is that we have limited block processing speed so a million straight lines make for a stuttering and long running program. I just made a program using 3D contour and loosened up my tolerance and smoothing numbers and it made it run better, but my part looks like a hexagon now. Is there any way to get this to post more I/J coordinates to smooth out the rounded surfaces, or because of its odd shape am I stuck with a million line segments to get the detail needed? At the end of the day I can hand polish these one off weird parts to get the finish I want as post process, but it would be nice to shorten the run time.

Re: 3D machining, Smoothing, I,J output, Limited block processing speed, etc.. H

HughesTooling — Wed, 27 Jun 2018 17:23:52 GMT

Personally find a smoothing value 2 to 5 time the tolerance work best for arc fitting. As you've found the total tolerance is both added together, for bigger parts I use 0.01mm for the tolerance and 0.02mm for smoothing. Something like 0.001 and 0.005 give good results on small parts also get good arc fitting on larger parts but takes a while to process.

On this fairly simple part I'm using a parallel cutter to generate a draft angle with small stepdowns. Using 0.005 and 0.01 each level is coming out as 4 lines and 4 arcs, the transitions are the biggest problem as they are about 30 lines each!

Of course it will all depend on the part and if it's made from true arcs, if the part below had elliptical corners the fitting would not work so well. Best to just experiment and note the toolpath size in the op.

Mark

Re: 3D machining, Smoothing, I,J output, Limited block processing speed, etc.. H

cmleschak — Wed, 27 Jun 2018 18:00:24 GMT

I played with it a little bit and using .001 and .005 reduces about 1200 lines of code. I will try machining the part like this, but there are still a lot of line moves.

Again, these parts are rare and to the extent of mildly ridiculous shapes, but I enjoy pushing these machines and designs to the limits. These are lofted bosses that are constantly changing shape so it makes sense that there are not many places where radii will fit in.

We also have full on CNC machines that will handle these parts with no problem, the problem is they are running production 99% of the time and the old dynapath that nobody else in the shop wants to touch is almost always available to use, haha.