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Author Topic: 'Jerky' movement - Help please!  (Read 4220 times)

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'Jerky' movement - Help please!
« on: March 30, 2008, 03:44:56 AM »
Hi all.

I have recently finished (Is there such a thing as finished?  ;) ) my 3 axis router table, however it is very 'jerky' when cutting....Or more to the point, it pauses between lines of G-Code.  The resulting finish is very staggered, instead of smooth.

Is there a way to get Mach3 to remove this momentary pause as it is causing me some headaches at the minute.

I have played with the accelerations, but can't seem to get rid of it.

Any suggestions anyone?

Cheers.

Dwane.

Offline Sam

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Re: 'Jerky' movement - Help please!
« Reply #1 on: March 30, 2008, 04:14:10 AM »
Most likely your in exact stop mode. Go to the menu at the top... CONFIG>GENERAL CONFIG. The setting should be listed there. Switch it from exact stop to constant velocity.
And no, there is no such thing as finished.
"CONFIDENCE: it's the feeling you experience before you fully understand the situation."
Re: 'Jerky' movement - Help please!
« Reply #2 on: March 30, 2008, 04:38:10 AM »
Thanks Sam.  I'll see if that helps tomorrow.  (Neighbours have a problem with my router running in the middle of the night!)

Cheers.

Dwane.

Offline Sam

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Re: 'Jerky' movement - Help please!
« Reply #3 on: March 30, 2008, 04:56:41 AM »
The only good neighbors are ex-neighbors. Just do what I do. Take the M-16 out every now and again, just to remind them who there not going to deal with. If that don't phase them, just wear a helmet and put on some bunny slippers while  your shooting. Be creative.  Ever had your house shake because the neighbor is cutting down trees...with black powder charges? Naaaa, CNC at 3:00 am is small potatoes. 4 neighbors...and counting. I just hope some crazy person don't move in. Keep in mind when you go from exact stop to const. velocity, you might have to mess with the CV angle setting. If you try to go fast around corners that are supposed to be sharp, they can end up rounded. Just a heads up. Might want to read up on the subject in the manual.
"CONFIDENCE: it's the feeling you experience before you fully understand the situation."

Offline Hood

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Re: 'Jerky' movement - Help please!
« Reply #4 on: March 30, 2008, 05:53:03 AM »
Also be aware that your code can change the CV/Exact Stop settings on the fly. If your code has a G61 in it then it will change to Exact Stop, G64 and it will be Constant Velocity. So even if you change you Mach setting to constant velocity (CV) then your code may switch it back to Exact Stop if there is a G61 in it.

Hood
Re: 'Jerky' movement - Help please!
« Reply #5 on: March 30, 2008, 08:12:11 AM »
The only good neighbors are ex-neighbors. Just do what I do. Take the M-16 out every now and again, just to remind them who there not going to deal with. If that don't phase them, just wear a helmet and put on some bunny slippers while  your shooting. Be creative.  Ever had your house shake because the neighbor is cutting down trees...with black powder charges? Naaaa, CNC at 3:00 am is small potatoes. 4 neighbors...and counting. I just hope some crazy person don't move in.

Ain't that the truth!  Sadly though, I live in a block of 6 units, all in fairly close proximity.  (However there has been the odd occasion when I have been tempted to call a mate to bring some 'force' over to stop the noise at all hours!).  So noise can be an issue for me.  Plus it's too cold & miserable out there tonight.....Best left till daylight.  I might slip out to give this a dry-run though.   ;)

Keep in mind when you go from exact stop to const. velocity, you might have to mess with the CV angle setting. If you try to go fast around corners that are supposed to be sharp, they can end up rounded. Just a heads up. Might want to read up on the subject in the manual.

I'll bear that in mind.  Still doing the usual learning curve stuff here, but I have no doubt that with the support Mach has to offer, I will work my way through it.  I still have to sort out clamping yet.  The old g-clamps are getting more and more in the way with each cut!
Re: 'Jerky' movement - Help please!
« Reply #6 on: March 30, 2008, 08:14:38 AM »
Also be aware that your code can change the CV/Exact Stop settings on the fly. If your code has a G61 in it then it will change to Exact Stop, G64 and it will be Constant Velocity. So even if you change you Mach setting to constant velocity (CV) then your code may switch it back to Exact Stop if there is a G61 in it.

Hood

My g-code is very basic and doesn't use many of the more advanced codes that are available, so I don't think that G61 and G64 will be a problem, but I will keep that in mind.

Thanks Hood.   :)

Dwane.