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The Voron kit build thread
- Thread starter Ken226
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- Jan 6, 2017
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In Prusa Slicer, the limits, build plate size, etc for the pre-configured Voron profile are locked for editing. The wizard allows to you select the Voron version and size when setting the profile, but not edit the parameters within the profile. At least, if there is I havn't figured out how to do it yet.
I assume that the limits are in those locked settings as well, since I can't find them anywhere that's accessable.
The build plate size/shape is the closest thing I could find to limits, but its all set correctly.
There is a "limits" tab, but it contains speeds and acceleration rates. Nothing to do with X, Y travel limits.
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If you click on the lock next to a value you can unlock it. Make sure the Expert level has been selected so everything is visible. Nothing should be hidden at that point. I doubt Prusa Slicer will send the printer anything outside the slicer set limits unless it is explicit in one of the gcode sections. I would think the "real" travel limits would be set in Klipper and neither Prusa Slicer nor gcode would be able to override Klipper limits.
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I have "expert" selected, and am able to access all of the settings.
But, everything appears to be correct.
I resliced the model with Cura, and it seems to be running great. It's halfway done and no hiccups yet.
I have no idea what the problem was, but i'll be using Cura until or unless I figure it out.
Everything in Klipper, Cura, PrusaSlicer sets limits in the positive direction. So, with the origin in the front left corner @0,0 the end stops are positioned and x300 and y300. To crash, something sent the X to a value above 300, yet there didn't appear to be any commands for X > 300 in the gcode.
My best guess is that either @pdentrem is right and it lost home somehow, or a glitch of some sort resulted in an absolute command being mistaken for incremental, or vice versa.
Klipper doesn't appear to use end stops as limit switches the same way that a cnc mill does. On my mill, when a switch is triggered, everything locks down immediately, full-stop.
It's possible that one of PrusaSlicers default accel or speed values is too high and a stepper missed steps trying to keep up, causing it to lose home. I'll have to look at the speed/accel settings in PrusaSlicer and compare them to Cura. It's running perfectly on Cura code.
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You probably checked all this already. Just reviewing the docs in case something was missed. I'm also learning Klipper, I'll be doing similar things very soon.
I'm focusing on how Klipper commanded the motor to hit an endstop at speed. I'm not convinced that missed steps is likely, but that is a reasonable possibility. Usually it is something more fundamental. Once the hardware is protected then taking risks with various software is more reasonable. The underlying hardware settings should be correct first. The Klipper accelerations and velocities can be reduced to insure there are no missed steps. Perhaps cut them to some fraction of defaults just to rule that out. Cura and Prusa Slicer settings should not override Klipper settings.
Scale of X and Y motions precisely correct?
X and Y axis settings:
Position min?
Position endstop?
Position max?
Microsteps?
Rotation Distance? Pulley circumference?
Full steps per rotation? (0.9:400 or 1.8 :200 A/B steppers?)
Gear ratio? (probably should be undefined?)
Multiple config files with different values overriding the proper ones?
Desired values set but commented out? Or set in a file that is not being referenced/read by Klipper?
Other ideas??
I'm focusing on how Klipper commanded the motor to hit an endstop at speed. I'm not convinced that missed steps is likely, but that is a reasonable possibility. Usually it is something more fundamental. Once the hardware is protected then taking risks with various software is more reasonable. The underlying hardware settings should be correct first. The Klipper accelerations and velocities can be reduced to insure there are no missed steps. Perhaps cut them to some fraction of defaults just to rule that out. Cura and Prusa Slicer settings should not override Klipper settings.
Scale of X and Y motions precisely correct?
X and Y axis settings:
Position min?
Position endstop?
Position max?
Microsteps?
Rotation Distance? Pulley circumference?
Full steps per rotation? (0.9:400 or 1.8 :200 A/B steppers?)
Gear ratio? (probably should be undefined?)
Multiple config files with different values overriding the proper ones?
Desired values set but commented out? Or set in a file that is not being referenced/read by Klipper?
Other ideas??
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- Jan 6, 2017
- Messages
- 1,249
So, yes I went through and checked all that, the min/max positions, endstop locations are right. My Voron test cubes were dimensionally correct to about .04mm.
I certainly appreciate the effort you've put into helping, but I think I've figured it out, and --maybe-- fixed it.
I think the X/Y belts were too tight, causing missed steps. Testing the theory now.
I came to that conclusion by comparing the Cura code to the PrusaSlicer code. The only major difference was that Cura was ALOT more conservative with the g00 rapid travel while not extruding. Like, Cura was travelling at 200 mm/s and PrusaSlicer at 300mm/s.
So, I started jogging the carriage around at 300mm/s and it started occasionally missing steps. I kept reducing the jog speed untill it stopped missing steps, which occurred at about 220 mm/s.
It's supposed to be able to handle 300, so I started checking everything I could think of.
I downloaded a different audio spectrometer app and started plucking the belts like guitar strings. It showed 200hz. I backed off the X/Y belt tension untill it showed 140, the spent about 15 minutes jogging it around at 300mm/s. No more missed steps.
I'm running the PrusaSlicer code now, to see what happens.
Good detective work. Glad you are finding the issue. Those belt tensions did seem higher than I expected.
I installed the lighting in the Repbox and put it on the shelf. The room lighting needs work, the Repbox LED lighting is very bright at night. Might be better with something different there, light the filament more and the acrylic less perhaps. Still waiting for the bowden tubing for the filament. Watching the Relative Humidity go down in the box. The research I've done on RH says that less than about 35% is fine, it doesn't have to be near zero. It's around 50% in the house so it doesn't take a lot to be good enough, it's already down to 32% and it hasn't been closed up very long. I have four of the little aluminum dessicant tins in there now. There isn't a lot of room for them, so I'm thinking about 3d printing some dessicant bottles that will fit inside the spool cores. Each time I take a spool out I can check the indicators in the beads, or anytime the overall RH seems to be higher than expected. Perhaps print them with clear PETG so they can be seen easily, and so they will stand up to the recharging process. Or just pour the beads onto a tray and spare the container that stress.
The support from Repkord has been excellent. Above and beyond. The box is well designed and sturdy.
Edit - after a couple of hours it is down to 27%. However these gauges are not very accurate, and I've heard they don't work well at really low values. Measuring RH accurately is not easy, but we're not that concerned.
Edit 2 - 22% early this morning. Clear PETG on order.
I installed the lighting in the Repbox and put it on the shelf. The room lighting needs work, the Repbox LED lighting is very bright at night. Might be better with something different there, light the filament more and the acrylic less perhaps. Still waiting for the bowden tubing for the filament. Watching the Relative Humidity go down in the box. The research I've done on RH says that less than about 35% is fine, it doesn't have to be near zero. It's around 50% in the house so it doesn't take a lot to be good enough, it's already down to 32% and it hasn't been closed up very long. I have four of the little aluminum dessicant tins in there now. There isn't a lot of room for them, so I'm thinking about 3d printing some dessicant bottles that will fit inside the spool cores. Each time I take a spool out I can check the indicators in the beads, or anytime the overall RH seems to be higher than expected. Perhaps print them with clear PETG so they can be seen easily, and so they will stand up to the recharging process. Or just pour the beads onto a tray and spare the container that stress.
The support from Repkord has been excellent. Above and beyond. The box is well designed and sturdy.
Edit - after a couple of hours it is down to 27%. However these gauges are not very accurate, and I've heard they don't work well at really low values. Measuring RH accurately is not easy, but we're not that concerned.
Edit 2 - 22% early this morning. Clear PETG on order.
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Funny you should mention that RH meters aren't accurate down low. I have two humidity temperature meters. They measure a minimum humidity of 20% and 13%. I tried making one from an I2C sensor and a low power Arduino. It reads -6%! Reading the IC spec says that is possible. So accurate RH sensing isn't easy and one should expect to read to 18-20% but most sensors bottom out near there. I clamped the Arduino output to 0, but have no idea what the real relative humidity is. Oh, the temperature of the Arduino sensor is elevated due to the heat generated by the Arduino chip, about 4F higher than expected.
I see that the "type" of budget temperature/RH readout used in the Repbox can be purchased from Amazon in a four pack for well under $20, so not surprising they aren't the best (I am not saying this is the exact model they use, it might be they use a higher quality unit). I have a handheld RH meter that seems to work but the calibration and accuracy of all these devices is quite suspect, it never seems to read very low, but since it times out it is hard to get a dry box reading. I may have to try something with a better sensor as you did. I do have some 13X molecular sieve for the high pressure air compressor that can dry to a lower RH but it is quite difficult to re-activate. It might be useful for some testing, but silica gel beads should be good enough for filament environment drying. Perhaps these inexpensive gauges can be mounted in a gamma seal to make checking the status of the dessicant inside easier to do. That's probably the primary utility they provide - a way to tell if the dessicant needs to be changed without opening the container and introducing more moist air.