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Author Topic: feedrate override & "jerky" motion??  (Read 2602 times)

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feedrate override & "jerky" motion??
« on: May 21, 2007, 02:46:19 PM »
so, here is my situation..  running a 3-axis gantry (with X & A axis slaved for the gantry) router...   I have rapids set at 6_ _ IPM on my Y-axis, and about 300 in my Z-axis.

I am cutting a convex contour in the Y-Z axis, and then an 1/8 stepover in the X... in foam (think blue house insulation panels).. many many many short little segments blended together...

I am using an AD DL06 PLC with an analog card to control my feed/speed over-rides.

If I set my feedrates at 500 IPM in the GCode file, I end up with some rather nasty, jerky motion... Ok.. so turn the feedrates down cause we're obviously pushing the envelope for the speeds the machine can be happy at.... So, I turn my feedrate down to 200 IPM using the feedrate over-ride... motion is still jerky... hmmm

I go in my GCode file, and set my feedrate at 200 IPM...  this time when running, the machine has got really smooth motion...  even @ 100% feedrate override..   i turn it down to 100 IPM using the feedrate over-ride, and motion is still smooth (which would make sense.. if it's smooth @ 200,  it's probly gonna be smooth @ 100)...

So, My question is this..  why is the machine behaving any differently when i set my feed @ 200 Vs 500??  the end result is still 200 IPM when the feedrate override is put in.... It's not really a HUGE issue, as i can take care of it by changing my hardcoded feeds.. i'm just curious as to why it's doing this...

any input would be great!

BTW.. eagerly anticipating Quantum on this machine.. it would be the bomb diggity for what we're doing :) :)
Re: feedrate override & "jerky" motion??
« Reply #1 on: May 22, 2007, 12:58:40 AM »
Nate there is an option in the General configs ... No FRO on Q .. Check this and it will run smooth again (This will make it so Mach is not changing time and Fing up the accels)

Later
Brian
Fixing problems one post at a time ;)

www.newfangledsolutions.com
www.machsupport.com
Re: feedrate override & "jerky" motion??
« Reply #2 on: May 22, 2007, 08:25:50 AM »
aHA!   i thought i had read something about that earlier..  but after sifting through so many posts...  i just couldn't remember anymroe..

I'll give it a go!  Thanks!
Re: feedrate override & "jerky" motion??
« Reply #3 on: May 30, 2007, 05:51:13 AM »
Hi, Brian

I installed the Quantum software on my welding machine and it works great, but
only the feed rate override doesn't work.

                                                                Kees.

                                         
Best regards, Kees
Re: feedrate override & "jerky" motion??
« Reply #4 on: May 30, 2007, 07:41:23 AM »
Kees,
The good news is that we will be working on that after we are done with Lcam :)

A few more months and I think we will be working on it.
Thanks
Brian
Fixing problems one post at a time ;)

www.newfangledsolutions.com
www.machsupport.com