UM3E Printhead issues

[STATS 0]

Hello, 

 

I am looking for some assistance on an issue I've been having with the Ultimaker 3 Extended (Firmware used 5.3.0). The print begins with print core 2 using PVA material on the base, the print head switches over to print core 1 and begins with the first green PLA layer with no issues. After the first layer has been completed the print head rapidly moves to the lift switch position but fails to correctly move the switch, causing print core 2 to be approx half an inch from the glass while extruding PVA material for a short time. The printhead then swaps back to print core 1 and continues printing the second PLA layer in a skewed/offset position. Prior to operating I have made sure to calibrate the limit switch with no issues. I have read from a similar post that this could be a firmware issue? Would anyone be able to help and if it is a firmware issue what would be the release needed to fix the issue I am having?

 

Thanks

[Dustin 129]

Shouldn't be a firmware related issue.. but if it is.. a factory reset should resolve it (you will need to re-do xy and lift switch calibrations)

But it sounds like the machine is having motion issues 
I would refer to the following guides for that.
https://support.makerbot.com/s/article/1667411552850
https://support.makerbot.com/s/article/1667411043559
https://support.makerbot.com/s/article/1667411151233

[Enigma_M4 119]

Hi,

aditional, checking for lose pulleys (especially on the shafts of the stepper motors) could be recommended.

Regards

[STATS 0]

Hi,

 

Thanks for both of your advice. I have followed the steps issued in the guides posted above. Both the stepper motors pulleys are taut and I've made sure to follow the steps with the long pulley adjustments. While doing these adjustments I noticed the X rod has a small amount of play back and forth. I have highlighted this from the pictures attached along with a 2 minute video clip which shows the moment the error occurs during the printing operation.

 

I've also made sure to perform a factory reset on the machine, redone the XY calibration and lift switch calibration but unfortunately the printer continues to malfunction at the same moment.

 

printerhead video.zip

[gr5 2,172]

Oh that is REALLY strange.  Dustin did you watch the video?

 

So the head reaches the end of travel.  Hard!  Which doesn't damage the printer but it should never do that. and for some reason the limit switch doesn't stop it's travel.  It shouldn't even be going that far.

 

I agree with the factory reset - that can fix things like steps/mm of travel.

 

Something is really strange.  Is it printing somewhat in the center of the printer?

 

I'd run the lift switch calibration 3 4 or 5 times in a row.  Make sure it seems consistent.  Not because the printer needs it to be run more than once but because the more times you do it, the more likely you will notice something.

 

Okay so I'd check the Y limit switch also.  There is a smaller rod that passes through print head left to right.  That should stick out to the left of the left sliding block by quite a bit so it can hit the limit switch (I believe that's correct and I'm not just confusing the UM3 with the UM2).  Manually push the head around (while at it notice if there is lots of extra friction and if so use a tiny bit of oil - one drop - on the rods).

 

So push the head to the back of the printer and watch to see if the rod hits the limit switch in the left rear corner.  You should hear it click.  If it's missing the switch then that could be your issue.  You might simply have to slide the rod a little more to the left through the left and right sliding blocks.

 

Or possibly the limit switch is loose and has moved too far to the rear of the printer and the blocks hit before the limit switch is triggered.

[Travis7s 25]

It kind of reminds me of an issue I was recently  having with my S5, where it seems like a bent limit switch causes all kinds of chaotic behaviour and weird crashes, so I would be checking your Y-Switch out more closely. 

 

 

Edited May 3, 2023 by Travis7s

[Dustin 129]

well that was a hard smack to the back of the machine..

To add to gr5's notes.. 
Check both Y AND X limit switches.. looks like the X is damaged too as it looks like the head bounced off the back of the frame too.. 

Considering you had a loose rod.. i would expect both limit switches are damaged..

I noticed in the video your machine has the signature creaking/cracking noises when moving around.. 
You should consider replacing all your belts (they are available from your local reseller).
Despite how they sounds its usually not a faulty bearing but rather dried out/worn out belts..

The process of replacing the belts will make accessing the limit switches easier as well so it would be recommended to do it all at once. 

[STATS 0]

@gr5 @Travis7s Thanks for your useful inputs. Yes the prints first layer is in the centre of the print bed. I've done what you said regarding the lift switch calibration. I have attached a recording of the fifth attempt , I didn't noticed anything unusual. I've attached a short clip of the Y switch clicking when push manually. I've also checked the limit switch test on the diagnostics page with all three switches showing good with an 'X' symbol.

Lift Switch Calibration.zip Y Switch.zip

[gr5 2,172]

OMG.  So those 2 videos look absolutely fine and normal.  Your issue has NOTHING to do with the lift switch and everything to do with the Y movement.  It moves just fine in the newer two videos but in that first video it SLAMS into the rear of the printer.  Ignoring the end stop switch completely.  Although it never should have gotten close to the end stop.  Something was really really messed up when it printed your part but then it's fine when you do other things.

 

I really don't know what is going on.  It's moving Y too far.

 

I was hoping that whatever the issue is, it would do it when calibrating the lift switch.  But for some reason it doesn't.

 

Are there any G92's in your gcode?

 

My next thought is some bug or plugin in cura is inserting a G92 - e.g. G92 Y100 into the gcode and it confuses the printer into thinking the print head is different from where it actually is.

 

Another thought is you have the wrong firmware that thinks you have an S5 printer and not a UM3 printer.

 

Is this a new printer?  Did you change the firmware just before getting this issue?  It's just a strange issue.  It actually looks like the steps/mm is wrong and causes it to move to far.

 

If you can find the exact gcodes where it moves and does the core switch then you could type those in manually and try to narrow down the problem.  Figure out when it gets confused about it's Y position.

 

I'd do that by putting the printer in developer mode (setting in the menus) and then ssh to the printer and use "sendgcode" commands to try to duplicate the issue.  No need to heat up any cores or print beds to simulate the problem.

 

Google this forum for "sendgcode" for more info.

 

Did you contact your reseller about this?  Are you like an individual with a tight budget or is this for a company printer?  If company printer I'd send it to the reseller and make them deal with this strange issue.  But they will charge a lot!

 

[STATS 0]

@gr5 Thanks again for your detailed reply. This printer belongs to my new employer, I've been told it hasn't been in use since before the pandemic. The plan now is too send it to a reseller here in the UK. I am still waiting on a few quotes for the service/repair. Once the printer is up and running again I will post an update on how the issue was resolved.  

[gr5 2,172]

Oh!  Well it might just need a little bit of oiling on the 6 gantry rods.  Use WD40 or just regular oil and a rag to clean the rods.