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Wonky cuts on diagonal???1/24
Having issues on the flat table when cutting on the diagonal and looking for some advise on what need adjusted, X and Y independent are fine but Y+Y are not, getting drift between point to point regardless of speed
No idea if this is related, but we occasionally had a problem of wonky diagonals and the machine would actually stop itself. I changed the setting in my various softwares to "Roll Around Corners" and have never had it since. Apparently, the machine was coming into the diagonal hot and didn't like it. We're running an SCM Pratix. Not a huge machine, but not a garage version either.
Have you checked the mechanical connection between the servo/stepper motor and ball screw? Just guessing since we have no idea what kind of machine you have.
I would hope the was software related as once that problem is found it is an easy fix.
If it is machine related my guess would be backlash in the X and/or Y axis. When traveling in a straight axis direction that backlash would only show up as a slightly shortened cut.......if at all. However when both axis get involved at the same time a backlash problem could lead to noticeable loss of accuracy in the diagonal cut.
You can check for backlash by cutting and then measuring a large square........say 3'x3' or larger.
I would say check the mechanics of the machine first but here's another thought is your materials flat before vacuuming down I have seem a warped sheet cut crooked
Machine is a Busellato jet4 using CV integration,
Pdub, my roll corners was NO, just changed to YES and I'll check.
rich.c, all connection are good,
B.H Davis, the X runs on rack and is fine, Y on belt drive and is tight and squares are good, circles are oval though,
Jarvis, vacuum is great.
Was told by a tech that drive needed adjustment?, and that I should be running diagonals at 4m per minute, no sure how that would be possible in the middle of a nest when everything else runs at 18m
If the squares are dead on then I'd think it is software related. The oval shaped circles could also indicate a backlash problem if they are out of round by a very small amount. But if the squares are true then that shouldn't be the issue.
I don't claim to know more than the tech but 4 meters per minutes translates to 157.4 inches per minute. That is really slow for nested base cutting. I find it hard to believe the machine would require that speed in order to be accurate.
I too, am using CV. I changed the "Roll Around..." in there and Alphacam and that took care of it.
Do you see any "bumps" around the circles that turn out as ovals? If there are imperfections just before or after 3 and 9 o'clock on the circle then I would suspect an issue with the X-axis. If something is happening at 12 and 6 o'clock then the Y is the problem.
If its a smooth oval then one axis is accelerating faster than the other. But if this is the case the problem should be less noticeable as the speed decreases.
The machine should be able to route a 100mm circle at 6M/min within 0.2mm of perfect.
Just tried your suggestion and at 4m per min everything is perfect, at 18m per min the circle is egg shaped +2mm at 10 and 4 o'clock, also included a diagonal square and cut line drift's about 1.5 mm from corner to corner (long bow), "roll-around" on CV made no difference
Most machine manufacturers have either shape macros or a test cut built in to the controller. if you run one of these from the controller using your normal cut speeds and it cuts fine, it is a software issue, if it doesn't cut fine, it is a hardware issue 99% of the time. Check your bearings, gears and other mechanical links for binding. Also did this just appear out of nowhere or has it been progressing gradually? Has anything changed? Computer update? New operator?
used machine, big company owned so no reason for selling other than typical upgrade, machine has had issue since I've owned it, tech mentioned drive adjustment over phone but who knows, mechanically the machine is GREAT, previous owner barely used the router, seldom use for routed table tops off beam saw and replaced with new p&r busellato
Thinking there must be an acceleration problem as Kevin Simmons mentioned as the problem magnifies with speed increase
Vacuum good, bit's sharp, everything squared away
Normally its' mechanical have you checked to your pinions, a pinion should look like devils tower with the flat plateau, not a sharp mountain peak. If your gears have worn down to a sharp point, you are no longer engage into your rack firmly.
As to replacing the drive,, if thats a possibility try moving your axis a certain distance say 48" and measure that distance, I would think if your drive is the problem, it would be losing step along the way.
Replacing the drive would be the last thing I would point to being a tech.
Pinion looks good 2mm flat on type with even wear, no slop on ball in Y axis either, belt tight as well
When you engage the pinions into the rack, with the drives disengaged, if you wiggle the gantry back and forth can you feel any backlash
Regarding the ball screw assembly on the Y-axis there might be some back lash adjustment built into the design. If so you should go through that adjustment procedure.
Your statement of only a few mm out of round on a circle cut does seem to indicate a hardware issue.
Kevin, just an FYI - Kevin Simmons is a FST that worked for Delmac for about 15 years. He knows his stuff!