2024 05 31 Mastercam Unified Jitter in Motion

Mastercam's Unified toolpath set to Flowline is resulting in some jitter on the machine! Why is that? Follow along to learn a bit about Tool Axis Control strategies and tolerance stackup.
Use Machine Simulation to diagnose the issue
Original Post: / 1848585572327847
Download the example file: vectormfg-my.s...

[@simonbackman7997]

As Always, Amazing video! Learn so much everytime you upload.

[@CADCAM-qu5oo]

awesome

[@cristinelpricop]

thanks. Yeah, can you please explain more the singularity situation and how pros' are managing it?

[@icey_b1562]

Aaron can explain it better. I’ll try. .. There’s either more than one solution to the problem for a position or the algorithm has to divide by zero which is impossible. Can crash machines or post incorrectly. I’m just getting into this stuff to but I know singularities are an issue with robotic arms when joints are at a straight 180 degrees. So you have to program around that.

[@VectorMfg]

@@icey_b1562 Great go at it :)

[@VectorMfg]

Sure, I'll try to find time to make a video on it, but basically, when two axis get perpendicular to each other, there's theoretically an infinite number of solutions as to which way a it can tilt through it. Picture what happens when a tool has to cross over a dome right at the very top of it on a BC or AC rotary table machine. When it's tilted right before traversing across the top, there's an easy-to-calculate value that the B & C axis have to be tilted, but, when you cross over the top of it, there is a point where either axis can move in any direction and still be tangent. When that happens, the post processor is calculating moves below the limit of the tolerances, so it'll prioritize one axis over the other. This often results in a small B move, but a 140° C move. The easiest way to avoid it is to simply not let the algorithm tilt through 0° if you can avoid it, then you'll never need to worry about it. In my example, I told it my tilt was allowed to be anywhere from 2° on, so it avoided that.

[@7077nghenhac]

You have nice video

[@samstearley9707]

Thanks a ton for making this. I learned a lot in a hurry. Can you give a brief explanation of what you mean by singularities? (10:05)

[@VectorMfg]

You're welcome! Copied my reply from above just to make sure you got notified :) Sure, I'll try to find time to make a video on it, but basically, when two axis get perpendicular to each other, there's theoretically an infinite number of solutions as to which way a it can tilt through it. Picture what happens when a tool has to cross over a dome right at the very top of it on a BC or AC rotary table machine. When it's tilted right before traversing across the top, there's an easy-to-calculate value that the B & C axis have to be tilted, but, when you cross over the top of it, there is a point where either axis can move in any direction and still be tangent. When that happens, the post processor is calculating moves below the limit of the tolerances, so it'll prioritize one axis over the other. This often results in a small B move, but a 140° C move. The easiest way to avoid it is to simply not let the algorithm tilt through 0° if you can avoid it, then you'll never need to worry about it. In my example, I told it my tilt was allowed to be anywhere from 2° on, so it avoided that.

[@icey_b1562]

Random C140. ??! Do postability post catch those moves? We have CAMplete at work but it isn’t setup yet. I’ve got a part at work that may have similar issues if i’m not careful to programming. But that seems easy to do b

[@VectorMfg]

In a lot of cases, a well set up post will avoid it. Postability is about the best in the business so you probably won't have too much trouble. In general, it's good to avoid cutting on the tip if you can avoid it anyway, so it generally doesn't hurt to use a touch of tilt, Even if that specific problem is solved by your post.

[@samstearley9707]

@@VectorMfg Thanks for explaining!