X-Axis crash against frame halfway through print for no reason
Hello,
Please forgive me if I don't explain this well enough, or if I over explain it, as I am still new to 3D printing.
Current Firmware is 3.7.2-2363
I have had my MK3s for just over a month now and have only been able to get 3 complete prints from it, 2 of them were perfect and the other one was a very large one that had a noticeable layer shift on the X-Axis.
All of my prints start just fine, however around 30-45mins into the printing process it just stops printing, the Extruder then proceeds to move all the way over to the right until it hits the frame (the side with the PSU). The current print is obviously stopped because a "crash was detected," however if I press continue print it just continues to crash into the frame.
It seems that every time it crashes against the frame, all of the axis coordinates are reset to that position, and that becomes my new "home" position? If I go into settings and try to move the X-Axis left I am unable to because it thinks that is my new X0 position. Going into Calibration > Autohome just keeps the Extruder in the last position it crashed against the frame.
The only way I know how to resolve this is to run an XYZ Calibration. So for the time being if I want to try to print something I have to run through an entire XYZ Calibration as well as a First Layer Calibration, all in the hopes that the print will actually work.
I do want to note that I do have another 3D printer, a JGMaker Magic. This printer has no problems running the same files.
Here is what I have tried to resolve this:
I tried printing the GCode from the SDcard that came with the printer - it still fails
I double and triple checked that all connections are secure and the printer is assembled correctly
I tried using another SDcard just in case something was wrong with the one that came with the print
In case something was wrong with the SDcard and files that came with the printer, I downloaded the buddy.gcode from https://www.prusa3d.com/layer-shifting/
Attached pictures are of the last print and where it crashes into the frame
Thank you for any help you can provide. I'm really hoping its something stupid I'm overlooking.
RE: X-Axis crash against frame halfway through print for no reason
Part of the magic of the Prusa Mk3, is Sensorless homing... however this is a double edged sword.
If there is a restriction to movement, then the rehoming after a crash, can rehome to another position, ruining the print in progress.
when the power is off (or the printer is sitting idle), the X and Y carriages should move smoothly, if there is any significant resistance to movement, then the problem you have, can strike
try moving the X carriage from left to right by hand, and feel for any unexpected resistance.
If there is resistance, the causes could be many and varied,
assuming your X carriage, extruder and Pinda probe are not catching on anything... (there is no particular order to the following comments (it's just the order they fell out of my grey matter!))
1, is your X motor pulley fitted with the clamping screw towards the front (as far away from the motor as possible whilst keeping the belt aligned)(back to front, compared to normal installation)
2, are there any scratches on your smooth rods? (you may have a faulty bearing)
3, try loosening the X carriage rear cover screws a little, and try moving the carriage again... if this eases the situation, re tighten the screws one at a time and see which is causing the problem
4, check your X carriage, cable bundle is not catching on anything.
5, Check your smooth rods are clean and lubricate with light oi
6, could the X axis Belt be too tight? or have some debris trapped in the teeth
7, there is a screw mounting the X belt Idler on the right hand side. there is nothing to stop you tightening this screw too much and causing friction between the plastic parts and the sides of the idler wheel, try loosening it, a turn. (there is a Nylock nut behind the right hand X axis end piece, so the screw will not fall out)
8, is there a 'clicking' sound coming from the right hand side of the X axis... the Idler bearing could be faulty/collapsing... I have had this problem, I now replace the idler with aftermarket twin bearing, toothed idlers... (as a matter of course...) they are easier to replace during assembly than they are after assembly
If there is still a problem, consider turning crash detection off, and running the printer for a couple of prints to see if the printer 'Beds in'
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: X-Axis crash against frame halfway through print for no reason
Perform a self test. Note the BELT TENSION numbers (ignore them, but write them down).
Power off. Add a few drops of light machine oil to the rods, both sides of the bearings, work the extruder side to side until you feel it start to slide freely and the oil is worked past the grease seals and into the bearings. Do this for both X and Y rod sets. There should be absolutely no rough or sticky spots as the bed and extruder move through their range stop-to-stop.
Perform another self test. Note the BELT TENSION numbers (ignore them, but write them down).
ps: grease on the rods usually doesn't help; grease packed into the bearings before assembly does.
Motor oil will work, 3-in-1 oil, sewing machine oil, anything you have on hand.
And make sure your USB cable is underneath and clear of the extruder harness - and I'd get those power cables away from the bed. The printer needs to have no obstructions anywhere near any of its moving parts.
RE: X-Axis crash against frame halfway through print for no reason
Thank you for your replies!
I will check and try all of the above and report back
RE: X-Axis crash against frame halfway through print for no reason
Stab in the dark suggestion:
Loosen the 5 screws holding the X axis bearings in by 1/4 turn.
RE: X-Axis crash against frame halfway through print for no reason
X-Axis crash against frame halfway through print for no reason
Just read the title with my "English is an odd language" hat on: Since the event happened for NO REASON, there is no solution. Right?
RE: X-Axis crash against frame halfway through print for no reason
I believe I got it working thanks to everyones advice.
- I loosened the pressure on the X-Axis bearings
- I also loosened the X-Axis belt and noticed that the X motor pulley was pushed against the motor, so I pulled that out.
- I also loosened the X-Axis belt.
- The X-Axis now glides MUCH more smoothly and an initial test print ran smoothly.
I guess the only question I have left is why any of these would make the extruder crash into the frame? As stated in the original post, while the extruder was in the middle of the X and Y axis it would just stop and move all the way over until it crashed into the frame.
I wish I had a video of what it was doing, but out of fear of damaging a motor I didn't want to continue doing it.
Thank you all again for your help!
RE: X-Axis crash against frame halfway through print for no reason
It's a bit of a deep dive to understand why the printer loses it's brain.
HOME is where the printer finds itself before printing. HOME is where the printer rams the X and Y axes into a hard stop. Z is found using the PINDA detection.
This is the only positional feedback the printer has: these two hard stops, and the one soft stop. All subsequent moves are based on those three positions in space: 0,0,0.
If CRASH detection is on, the controller can sense a motor has stalled by monitoring the current required to make a step: with CD on, the printer will stop the print. If CD is OFF, these printer ignores the motor feedback and ignores these crash stalls. Generally, a crash can be one or more steps, and the controller only knows it missed a step, but not how many steps were missed. If it missed 5, 50 steps or even 5000 steps is an unknown. Using X as an example, the motor hits a sticky bearing spot and stalls for 200 steps, equivalent to a full rotation. The extruder is now 200 steps offset from where it should be. When the motor recovers from a stall, the controller is unaware of this offset, and all subsequent moves are 200 steps from where they should be. In most cases this cases a layer shift like the image below. If no more stalls happen, the part continues to build normally, but with the offset added. And yes, shifts can go either direction if the motor happens to stall when moving the opposite direction.
RE: X-Axis crash against frame halfway through print for no reason
I guess the only question I have left is why any of these would make the extruder crash into the frame? As stated in the original post, while the extruder was in the middle of the X and Y axis it would just stop and move all the way over until it crashed into the frame.
I wish I had a video of what it was doing, but out of fear of damaging a motor I didn't want to continue doing it.
Thank you all again for your help!
Which firmware do you currently use? Have you ever tried an older firmware (for example, 3.5.1)?
2x Personal MK3IR-BMG09 (Full) BEAR + MMU3 mod., ...
RE: X-Axis crash against frame halfway through print for no reason
If CRASH detection is on, the controller can sense a motor has stalled by monitoring the current required to make a step: with CD on, the printer will stop the print. If CD is OFF, these printer ignores the motor feedback and ignores these crash stalls. Generally, a crash can be one or more steps, and the controller only knows it missed a step, but not how many steps were missed. If it missed 5, 50 steps or even 5000 steps is an unknown. Using X as an example, the motor hits a sticky bearing spot and stalls for 200 steps, equivalent to a full rotation. The extruder is now 200 steps offset from where it should be. When the motor recovers from a stall, the controller is unaware of this offset, and all subsequent moves are 200 steps from where they should be. In most cases this cases a layer shift like the image below. If no more stalls happen, the part continues to build normally, but with the offset added. And yes, shifts can go either direction if the motor happens to stall when moving the opposite direction.
That makes much more sense when you put it that way. I do a lot of programming, but know very little about G-Code (so far), and this would have driven me crazy until I found out a possible cause. Thanks for clarifying
RE: X-Axis crash against frame halfway through print for no reason
I had exactly the same problem as the one described here. It happened on the first print after I had updated the firmware, but this was just a coincidence. Loosening the five screws holding the x-axis bearings and lubing the x-axis bar did the trick. My printer has been working perfectly since.
RE: X-Axis crash against frame halfway through print for no reason
@tim-m30
Perform a self test. Note the BELT TENSION numbers (ignore them, but write them down).
Power off. Add a few drops of light machine oil to the rods, both sides of the bearings, work the extruder side to side until you feel it start to slide freely and the oil is worked past the grease seals and into the bearings. Do this for both X and Y rod sets. There should be absolutely no rough or sticky spots as the bed and extruder move through their range stop-to-stop.
Perform another self test. Note the BELT TENSION numbers (ignore them, but write them down).
Thanks - this did the trick for me, very helpful. In retrospect it makes sense that the Belt Status numbers change after lubricating the x axis - good to see the result. Mine went from ~233 (after I had already loosened the belt tightness a bit) up to 270 - and it feels much smoother when moving it manually along the axis.
RE: X-Axis crash against frame halfway through print for no reason
I won't say which lubricant I chose and how I applied it, but this solved my problems. I assembled my 3s a few weeks ago, it worked great out of the box. But got noisier and then started presenting the crashing symptoms in this article. Screw and belt tension weren't likely problems for me because it had "just" been working well.
The kit assembly instructions said not to lube the bearings, so I didn't. But I'm annoyed that they already need maintenance.