Smoothing? <resolved, bad ballscrew support bearing>

[JayCNC]

I've been having an issue with my machine that I thought was a rigidity problem but after making some changes to it I've found that it was not the source of the problem I'm having and I'm convinced it has something to do with a software setting of some sort. So here's the problem... When contouring a part, I get really good surface finish in both X and Y, but not when both are moving, say on a 45 degree cut. Almost like a bad chatting is going on, but now verified it's not. Circular isn't as bad, but still not the best either. It's most noticeable on an exact angle. I've had the software smoothing set up as "Precision Mill", so I started playing with the settings. I really don't see any change when selecting a different preset, but there's definitely a noticeable change when turned Off. The finish is better, but still not great. The "chatter" looks more scalloped with it off, about 3/8" apart vs say every 1/8" apart. I'm running Clearpath servos 6400 res and tried running them at 800 as well with no difference. 1605 Ballscrews. Am I missing something here? It's got to be something with a software setting, right?

[todd432]

I too had a problem with smoothing, and thought it was the motors. Swapped out steppers for DMM Servos only to have the same problem.
Changed all kinds of settings , nothing fixed it. So I tried another controller PC...... bingo bang go, problem went away.
Might be worth a shot, if it easy enough to do on your machine.

[JayCNC]

This is the computer I'm using, should be well within the limits.

[todd432]

So was mine 1720 thread i5-2390T 2.7 ghz off from ebay.
Hooked it up to my cobbled to gather pc ,it did not meet the specs. E8500 3.16 ghz 1315 thread sons old gaming pc and it ran the file flawless twice.
I think it might have been the CPU or the Ethernet port on the mob. Some files ran good. AND ONE WOULD NOT RUN AT ALL.
I just assumed the PC was good.It work fine bench testing.
Todd

[agsweeney1972]

I've been having an issue with my machine that I thought was a rigidity problem but after making some changes to it I've found that it was not the source of the problem I'm having and I'm convinced it has something to do with a software setting of some sort. So here's the problem... When contouring a part, I get really good surface finish in both X and Y, but not when both are moving, say on a 45 degree cut. Almost like a bad chatting is going on, but now verified it's not. Circular isn't as bad, but still not the best either. It's most noticeable on an exact angle. I've had the software smoothing set up as "Precision Mill", so I started playing with the settings. I really don't see any change when selecting a different preset, but there's definitely a noticeable change when turned Off. The finish is better, but still not great. The "chatter" looks more scalloped with it off, about 3/8" apart vs say every 1/8" apart. I'm running Clearpath servos 6400 res and tried running them at 800 as well with no difference. 1605 Ballscrews. Am I missing something here? It's got to be something with a software setting, right?

Did you do any fine tuning to your servo's after you did the autotune? If you with the servo powered on and enabled grab the ball screw and give it a twist with you hand how far and easily does it move before the servo fights to get it back to position? The servo could be doing some "hunting" during the cut and you might need to make some tweaks to the tune.

[JayCNC]

I checked the holding on the servos and couldn't budge them but went ahead and turned them up to see if it helped and had no change. The finish on X or Y is perfect, it's only on angle cuts and slightly noticeable on curves or circles. I'm using Fusion 360 and have checked the "Points" in CAM and don't see any issues. I've also played around with some of the settings with smoothing in the Acorn software and can see some difference so that's what leads me to believe it's something to do with Acorn. I just don't know how to fix it...

[JayCNC]

Benchmark Rating 2083

[slodat]

Interesting.. My issue I'm having is only on the diagonals and after corners, with smoothing on. When I turn it off, I don't have near as much issue. I did measure some servo following error, so I was attributing the issue entirely to the servo's needing a gear reduction to put the motor in a better rpm range at lower cut speeds.

[todd432]

Jay, from what I gather smoothing dose change the code on the fly. That's why CNC 12 wants a min single thread of 1500 or higher CPU.
So any hiccup in the pipe line to BBG would show up in the motion control too.
The only other thing i can think of...... is maybe not having a dedicated video card on the controller PC might slow it down or chop up the code , but i don't know just a guess on my part.
Or a bad Ethernet port.
That's why maybe trying another PC to rule it out might be worth a shot.

[JayCNC]

Glad to see the GREAT help from the "Centroid" people as always. I suppose not being in the "In Crowd" gets you no where. Not the first time.

Thank you for the couple of people that suggested a few things.

At this point, I'm not impressed with much out of this forum. The few people that do help, only help the few. If this forum was created to help everyone like is said, then actually help everyone. I've asked a couple of questions in the past, and this is usually the responses I get, or a "watch this video" response, which I already did and it didn't help. You see, none of you know me on here, but I'm the type of person that doesn't ask for help, so when I do, I'm at the end of my rope and have no more options to explore. So to the "Centroid People" that are suppose to be here to help, THANKS FOR NOTHING!