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View Full Version : Dwelling too long in corners...



harryball
03-10-2008, 09:17 PM
Something changed when I upgraded to 3.5.5 and the bot began dwelling in corners too long. i.e.

When carving the 3D horse head it would exit the sweep, step, enter and sweep, exit, step etc... the steps were as long as 1 or 2 seconds where before they were smooth.

When cutting letters, when it approached some angles > 90 degrees it would have problems and go slow enough to burn the work.

When doing 3D tabs, again, on some it would go very slow leaving burn marks.

I checked everything, here are the values I was using...

3990

These are the same value I was running in 3.5.3 with no trouble. I'm running a PRT Alpha96 with the 7.2 upgrade.

I finally reset to default settings and the machine overall slowed down but was running much faster in the turns.

I discovered that if I set the XY Move Ramp Speed less than .4 the machine slows down on these turns, all other variables staying the same. The lower the number, the slower the turns.

The Minimum Dist to Check also has an impact, but not as dramatic. Lowering the number will speed up the turns slightly, but then the machine is banging around inside the cuts too badly.

I can set everything to default settings, change the XY Move Ramp speed to .1 and I see 90% of the problem crop up. If I also tune the Move Ramp Rate and the Jog Ramp rates back down to .1, the problem gets worse.

I'm not sure what is going on, I know with the 7.2 upgrade the suggested settings was .1 on these values. I don't know what changed from 3.5.3, it was working fine with that version. I even tried to downgrade and the problem persists.

I reloaded the firmware and double checked everything.

Ideas?

/RB

Brady Watson
03-11-2008, 02:31 AM
Robert,
Those settings are downright ugly!


Reset your config using the UR command and select the one for your PRS powered PRT. Adjust the following settings for all around good performance (as you have done above):

3D ramp Threshold = 150
Slow Corner Speed = 45
Min Dist to Check = .08

Leave everything else alone. Save that config as your 'Old Trusty' config & resort to it when you get into a situation like the one illustrated above. The Move Ramp Speed is only adjusted for intricate, small moves or really heavy metal cutting. Most will never need to adjust the value below .4 or so.

One of these days SB is going to post my column write-up on Ramping...still not up yet.

-B

harryball
03-11-2008, 10:05 AM
Brady,

My confusion comes with the change from 3.5.3 to 3.5.5. I can't understand why the behavior changed. I have 3 settings files, but all of them had .1's as shown above. Bumping the settings back up to .4 seems to have resolved most of the problems. When I finish this next run of 20 sheets I'll mess with it some more and see what I can learn.

/RB