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Messages - tlbokc

Pages: 1
1
Hood,

Thanks a million! Pulling out the "While IsMoving, Wend, DoButton( 29 )" corrected the problem.  Now the soft limits stay on when I hit "Ref All Home" to reset my XYZ home.  This will save us from hitting the switches when jogging and doing setups. 

Thanks again!

tlbokc

2
Here is the text in the "Ref All Home" button script:

DoButton( 24 )
DoButton( 23 )
DoButton( 22 )
While IsMoving
Wend
DoButton( 29 )

Thanks,  tlbokc

3
I have tried to post this twice. Maybe the third time...
OK, I'll try to realign the angles.  I have been hesitant to try because the angle are 2" x 3" x 3/16" and I don't know if I can get them any straighter (pictures attached).  The problem was made worse by the fact that they used top guide bearing and side guide bearings. As a first measure, I have backed off the side guide bearings. They were actually fighting the stepper motors through the arcs.  The problem is now much improved.  As for realignment, I would need a very accurate 8 ft straight edge, assuming the angles can be flexed into a straight path. Anyway, I will give this challenge further consideration.

Regarding the soft limits, I found the XML file on the drive computer.  It is attached to the previous post. Any suggestions would be appreciated.

Thanks, tlbokc

4
I am having trouble posting this. Sorry for the delay (its telling me I have already posted the file, so I renamed it). Attached is the XML file tlbokc.xml

Thanks,  tlbokc

5
Regarding the stepper motors: the problem is in the drive system. It is rather crude... a rack and pinion with the pinion spring loaded into the rack gear... runs dry.  Even with dry film lube the gears are galling each other and bind. Further, the carriage guide system is dual vee bearings  running on an angle iron track. The carriage long axis is driven by two steppers, one one each side, running in unison.  The carriage guide system runs in slight arcs, binding one motor against the other. When the tension gets too high, one motor must slip a few steps. This usually happens once each direction of travel along the long axis when cutting a 48" x 96" sheet.  I can't fix this problem without buying a better machine.  It's just not a good design.

Thanks, tlbokc

6
Sorry, don't know what an XML file is. How to find it?  I have a text file that is the router program. Is the XML an export from Mach 3?

Thanks,  tlbokc

7
This CNC router is running stepper motors without encoders, so when it misses a step, and it does miss steps, then it looses a little position. Each time I run the program, the program goes to "Zero" and rewinds. The program Zero is now flawed because of missed steps. So, before loading and running a new sheet I hit "Ref All Home" to reset the carriage to the machine limit switches.  When I do, the Mach3 refinds the XYZ limit switches as it should BUT turns OFF soft limits. If I hit "Ref All Home" again, it refinds the XYZ limit switches and turns ON soft limits. Every time I hit "Ref All Home" it toggles the soft limits.  (Just like pressing the soft limits button: press on, press off, press on, press off etc.)

Why can't the soft limits remain on until I turn them off?  Is there a preference setting that keeps them from toggleing on and off each time I use "Ref All Home?" 

Besides the extra wear on the machine, there is the constant opportunity to crash the switches when soft limits turns off automatically and the operator fails to notice it.

Thanks, tlbokc

8
General Mach Discussion / How to make soft limits stay on in Mach3
« on: July 24, 2012, 12:09:16 PM »
I am running a CNC router with Mach 3. To prevent step errors from accumulating, I hit "All Home" after each sheet is cut and the program returns home (program home, not hardware home). But here's the problem, I have to hit "All Home" twice each time because the first time turns soft limits off, the second time turns soft limits back on.  Or, I can manually turn the soft limits back on after "All Home" turns them off.  But why turn them off to begin with? It just costs extra steps. If you forget the step and don't turn soft limits back on, then you can crash the limit switches when jogging for setups, tool changes etc. Crashing the limit switches is big trouble on this machine... and its inevitable when soft limits is always toggling off!

Is there no way to make soft limits stay on until you ask them turn off?

Any suggestions would be greatly appreciated!

Thanks, tlbokc

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