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Author Topic: Jerky movement between strait movements and curves.  (Read 3899 times)

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Jerky movement between strait movements and curves.
« on: June 09, 2016, 07:13:53 PM »
Hey there guys,

    I've got a matsuura mc500v thats running under mach3 control with a csmio/ip-a controller and I can't seem to get the machine to smoothly transition between straight lines and curves. It's really always had this problem but I am needing to run it faster than I have been and the jerk is so bad that I'm tripping a following error (have my max following error set to 10000).

I'm using mastercam to generate the G-code. Here is a sample below. I can run the code, but only at a rate of 75 ipm. Mach will run smoothly until it gets to the G02 and g03 and suddenly there's a jerk than I can hear clear across the shop. It I try at 150ipm the machine will oscillate like crazy, throw a following error and trip my reset. Its almost as if Mach isn't looking ahead at the circular portions of the path. Or that when the machine arrives at a G02 or G03 command the machine ignores the axis max acceleration settings. ANy thoughts? Thanks for any and all help!

X-3.2416 Y-4.4236 Z.2779
X-3.2487 Y-4.4109 Z.2753
X-3.2552 Y-4.3979 Z.2727
X-3.2608 Y-4.3845 Z.2702
X-3.3469 Y-4.1632
X-3.3617 Y-4.1251
G3 X-3.3646 Y-4.1183 R.1125
X-3.387 Y-4.0863 R.1125
G1 X-3.4046 Y-4.0547
X-3.4184 Y-4.0237
X-3.4276 Y-3.9972
X-3.4336 Y-3.9743
X-3.4376 Y-3.9542
X-3.4423 Y-3.9199
X-3.4446 Y-3.8896

Offline Mogal

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Re: Jerky movement between strait movements and curves.
« Reply #1 on: June 09, 2016, 07:59:48 PM »
Is the exact stop checked in Mach settings?
(You'll want to use CV (constant velocity) but may lose detail depending on your speed and acceleration)
Re: Jerky movement between strait movements and curves.
« Reply #2 on: June 09, 2016, 08:18:58 PM »
I suppose I should have mentioned the obvious. The machine is definitely in constant velocity mode. And all other constant velocity settings are unchecked

Offline Hood

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Re: Jerky movement between strait movements and curves.
« Reply #3 on: June 20, 2016, 06:06:50 AM »
Sounds a bit like bad tuning or maybe you just have the acceleration a bit on the fast side although if that was the case then I would have thought doing a straight line 90 degree change would have been an issue as well. What kind of following error are you getting in the PID Tuning page and what is the steps per unit.
Hood
Re: Jerky movement between strait movements and curves.
« Reply #4 on: June 20, 2016, 11:12:40 PM »
Hood,

 I'm not sure. I'm sure my servos could be tuned a little better, but truth be told I've tuned them so many times I'm almost to the point where I'm over it. Back when the machine was missing steps due to the optocouplers they were more difficult to tune, so the new encoders have helped quite a bit. But I think the feedback from the servos to the drives are whats getting me know. I've adjusted the three potentiometers on the front of the servo drive to no avail.

The thing is, I had it running fairly well before I tried to reconfigure Mach for ridgid tapping. In the process of switching the spindle to the control of the ipa rather than the plc, I accidentally deleted my M6 macro and tried to recover it by reinstalling mach3. Ever since the reinstall, the machine has been having trouble. Its like its not capable of look ahead anymore. If I'm running a program at 45ipm and each point is only a few thou away from the next, say in the case of a helical plunge, the machine never has the chance to accelerate to the next point. So while the machine is commanding the drives to move at 45ipm its actually moving at 1 to 3 ipm. CS labs suspects that my mach3 file is corrupt. Don't know how that would happen, but I'll try downloading and reinstalling a fresh copy. I would make the jump to mach4 but rigid tapping isn't supported there and I've grown fond of rigid tapping.

Offline Hood

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Re: Jerky movement between strait movements and curves.
« Reply #5 on: June 21, 2016, 03:10:04 AM »
What version did you install, if 066 then get rid of it and go back to 062 or earlier, Ver 066 is screwed up.

Presume you have the look ahead set to a reasonable value?

No need to reinstall Mach if just wanting to make a new xml, just make a new profile but do not copy it from your current one in case the corruption (if it is corrupted) gets transferred, so just choose a default profile box and a new name then enter the values manually.

Hood
Re: Jerky movement between strait movements and curves.
« Reply #6 on: June 22, 2016, 08:01:58 PM »
Thanks Hood. I do have the 066 version of mach. Is there somewhere I could download an older version? Under the download page for Mach3 they only seem to have the 066 version and vista version.

Offline Tweakie.CNC

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Re: Jerky movement between strait movements and curves.
« Reply #7 on: June 23, 2016, 02:12:49 AM »
 If it's any help, the most popular version appears to be R3.043.062 and this can be downloaded from here;
http://ftp://anonymous:guest@machsupport.com/Mach3/Mach3Version3.043.062.exe

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: Jerky movement between strait movements and curves.
« Reply #8 on: June 24, 2016, 10:25:56 AM »
Hi, Tweakie.


That link doesn't seem to work for me. Is there an alternative? Thanks!

Jonathon
Re: Jerky movement between strait movements and curves.
« Reply #9 on: June 24, 2016, 12:31:34 PM »
Tweakie, I just realized that's an FTP link, so I think I just need to wait for you to be online, is that right? Thanks!

Joathon