Serious Trouble in finishing projects with my XL  

Fail 1 - Black LCD during printing

The first problem is a quite funny one ... at least until you want to swap filament mid print ...

That the LCD sometimes flickers is quite "normal" ... but usually it recoveres pretty fast from any data errors ... But in this case it completely crashed.

The display just was black with the backlight still on ... The print was going on and I was able to check on the print with Prusa Connect .. ok ... no loss here, but still a good idea to document 🙂

Fail 2 - Serious Layer shift

The second fail was quite severe.

You can see in the video that there are two objects on the print plate. The front one was canceled due to design issues (the outer layer was too thin so that there was no smooth surface and the inner coller showed through. I decided to reprint this object after changing the slicer details. The object in the back was almost done ... 2-3 additional layers ... Then a severe layer shift happened. After printing a layer with tool head 4, the tool head made some strange movements (not talking to move the the front object ... that's normal when an object is canceled ... somewhere in the gcode you have to sync) ... but before ... to the back right. After that movement the next layer was off by almost 2cm diagonally. After this layer finished, the next tool change of course failed since there was no way to park the current tool correctly.

• Wasted time: 48h
• Wasted filament: 457g (not counting the canceled object or cleaning tower)
• Wasted Energy: 10,2 kWh

Fail 3 - Extruder not spinning

This seems to be a quite common issue with firmware 6.2 ...

Nevertheless ... this is the third time I had this issue ... but the first two were not caught on video. I even followed the instructions of the displayed QR code. Two of the print heads now have removed the connector guard ... And the problem is moving as well ... the first two times it was extruder 2 ... this time it is extruder 4 ...

• Wasted time: 12h
• Wasted filament: 254g
• Wasted Energy: 2,5 kWh

Hm ... Video Player does not show up

At least in my browser the videos I uploaded to the media pool and linked on the posts don't show up ... I tried to use the embedded media player. I will poste the links in this post for you reference.

Fail 1

Fail 2

Fail 3

RE:

A flickering LCD is usually caused by a loose connection at one or other end of the cable.  Bring forward your next electrical maintenance session (and check the belt tensions as well)

https://help.prusa3d.com/article/regular-printer-maintenance-xl_401237

It's a bit hard to understand what's happening in the picture as we don't know what it should look like.  Save your project as a .3mf file

Files > Save Project as

Zip the .3mf and post it here. It will contain both your part and your settings for us to diagnose.

- having written that, I notice you are using organic supports - this is the sort of object for which I would consider snug supports to be better and if it were to go much higher I would change to grid.  If the supports are not secure the chance of the print tilting into the path of the toolhead and causing a head-crash increases.

Edit: Your videos have shown up.  Clean your print sheet.

Cheerio,

RE: Serious Trouble in finishing projects with my XL

Sure ... here you have the 3mf file ...

In this specific fase (fail 2) there was no broken support structure which might have caused the crash ... Funny ... when I initally was using classic support structure and chat support explicitly suggested organic support 🙂 ... But in this specific case I really can outrule a crash due to broken support structures.

The print sheet ... yes I know ... but it can't be cleaned better at this point of time. I am using a lot of silk PLA filament of different vendors for the metallic look for my robots. In the tiny structures of the satin sheet there always remain rests of the silk PLA filament. But I scrap the surface after each print and it is still flat and smooth, but looks ugly I have to damit. I already have a replacement sheet at home ... But as long the adhesion is good (sometimes too good) I continue to use the "dirty" one ... but I just can assure you it is flat and smooth ... no bumps whatsoever when you wipe it. When I have an adhesion problem, it is that the parts are currently sticking too well 😆 
The new one will look similar quite fast anyway due to the filament selection I am using. I can try using my textured one nevertheless. But it is difficult to see the root cause here for me.

RE:

I would never advise silk filaments for robotics or anything mechanical.  Because it expands on extrusion it destroys all tolerances - print-in-place bearings tend to seize and involutes and threads jam. Regular PLA is surprisingly good for the job or CF nylon for serious work.

It's not the feel of the surface that matters (strictly, you should never actually feel it as that transfers fingerprints), cleaning removes residues from previous prints that interfere with adhesion.

Support doesn't have to be broken to allow a crash, taller and narrower structures sometimes crash due to flex and rigidity becomes a factor.

As a rough guide: For simple shapes and most practical parts, snug support. For organic shapes with complicated surfaces (superhero figurines and a high proportion of 3d scans), organic support.  For anything over 15cm or so tall use grid support.

OK, now I've opened the file I see that some of the above doesn't apply.  

I still suggest snug supports.  If this is your design I suggest reducing the wide overhang at the back of the abdominal section, this sort of jutting section is prone to curling during printing and may have caused the crash - could you cut it away for separate printing and joining post-process?

The cubic fill you are using may be adding curling stresses, try adaptive cubic or lightening infill ... it should reduce build time as a side effect.

Cheerio,

RE: Serious Trouble in finishing projects with my XL

I will give the snug supports a try ...

The crash was at the very last couple of layers in of the object in the back .. so there haven't been any curling or even support structures at that position. The front object was canceled already multiple cm before ... so I have my doubts that a crash into sime printed structures occured ... frankly I am almost 100% certain. I know that can't be seen by the video very well ... but I observed the print ... there was NOTING in the way of the printhead.
The strange movement after finishing the layer before moving to the next one ... that's the key that has to be analyzed in my opinion ... The movement to the front object is normal .. but the strange swing to the right back is weird ... when looking closely frame by fame it might have crashed into the back of the printer though ... That's the point of time where everything got out of sync.

Fot the infill ... I used adaptive cubic before ... but it is quite buggy, at least with multi color prints ... In the center, where large structures would be ok it makes full support structures, while at the walls it leaves empty structures ... Let me give you an example of an earlier print ...

That's exactly why I changed back to regular cubic infill ... That works the best ... But i am using the automatic adaptation of the infill layer height ... so the infill gets printed in my setup only every 3rd layer ... so it is laid out quite loose ... I don't expect much curling stress here ... I am also printing with quite a lot solid layers .. that helped with the stability also.

Lightning Infill is also not an option ... The robots I am printing are quite large ... and I drag them around relatively often. So they need to be sturdy and stable ... But as I mentioned ... in this case there was no curling or broken support strutures or even warped support structures ... there was nothing in the way of the nozzle / extruder.

RE:

And yes ... I agree .. silk filament is not for mechanical components or "robotic" parts ... I referre to robots to huge "action figures" 🤣 

Like:

RE: Serious Trouble in finishing projects with my XL

Check your belts, and make sure your belt clamp is tight.  I found mine had worked it's easy loose causing issues. You need to pop the cover off the gantry to access it.

Definitely go thru the guide Diem linked and do the regular maintenance especially if this just started occurring. 

RE: Serious Trouble in finishing projects with my XL

Yes ... I will go through the maintenance ... the special grease for the linar rails are ordered, everything else I should have available in my lab. Checking tension and lubirikating the Z-spindles I am doing from time to time anyway. But I guess, I never really checked the pulleys and the belt clamp ...

I will do this right after the current print finished ... one way or the other ...

Fail 4 - Extruder 2 not spinning

Yes .. it happened again ... But I still was using firmware 6.2.1 ... so it partially might be my fault ... If it is a actual problem of the firmware ... that never should have happened in the first place! When I figured out there is a new one the print already was running.

Even though I followed the suggestion of the WEB-Page in the error screen and removed the guides from the cables on the two failing extruders (3x Extruder 2 and 2x Extruder 4) ... See image.

WHY is the error in such a case final? It should try to recover the print after confirming the error ... Even a Power recycle didn't restart the print ... It still was perfectly attached to the print plate ... so why ...?

Here is the video of the Fail ... as Link ...

I now will update to the latest firmware 6.2.2 ... and try again ...

• Wasted time: 7h
• Wasted filament: 129g
• Wasted Energy: 1,3 kWh

RE: Serious Trouble in finishing projects with my XL

Before I restarted the print with the new firmware I did some basic maintenance:

• lubrication of the Z spindles
• Check of belt tension (upper belt was still in the green region but on the lower limit, tightened it slightly to center the frequency)
• Check of belt clip (ok)
• Check of belt "synchronizity" (both sides of the bridge touch the front of the rails at the same time)
• Check of belt pullies (sitting on flat side on the motor shaft and tightened properly
• Cleaning of all print- and extruder fans
• Cleaning and brushing of nozzles
• Checked and reseated all cables for LCD/USB and all Extruder cables on both ends
• Checked output of Powersupplies (was curious since this might cause the issues I see when there is an instable power supply)
• Firmware update, of course

I didn't lubricate the linear rails since the special grease needed is still in delivery.

RE: Serious Trouble in finishing projects with my XL

Posted by: @m-j-caboose

The first problem is a quite funny one ... at least until you want to swap filament mid print ...

That the LCD sometimes flickers is quite "normal" ... but usually it recoveres pretty fast from any data errors ... But in this case it completely crashed.

The display just was black with the backlight still on ... The print was going on and I was able to check on the print with Prusa Connect .. ok ... no loss here, but still a good idea to document 🙂

Check the entire ribbon cable, just had an issue with the display going black after starting a print and the cable was being pinched, replacement cable solved the issue. 

RE: Serious Trouble in finishing projects with my XL

The belt tension phone app is good for a starting estimate but the homing tower is the real check to dial in correct tension.

I've also experienced those weird "why am I getting hardcrashes from simple parking/picking up tools when it looks perfectly fine" and the the issue seemed to be barely loose docks. Simply tightening the screw for each and redoing the dock calibrations was my fix.

Heh, my robots are very different:

@baconfase has a point, getting the docks perfectly into place can be tricky.

Look along the row of parked heads from the side, they should be perfectly in line - even 1mm out is enough to cause problems.

If you adjust any, you will need to recalibrate.

Cheerio,

RE: Serious Trouble in finishing projects with my XL

Also really cool robots ... 🙂 ...

The allignment of the docks seems to be fine ... but since increasing the belt tension slightly and the new firmware it is printing for a couple of days now ...

There is hope 🙂 ...

Fail 5: USB Stick corrupted

This happened a couple of days ago ... but since the XL was printing quite some time I reformatted the stick and started again ... But things are not developing great.

That's why I add this topic as well ...

Thankfully it happened during download from Prusa Connect ... and not mid print ... so the problem at least did't cost anything.

Prusa connect suddenly was telling me that there is no space left on the printer ... hm ... I checked the stick and was not able to read it anywhere ... So I reformatted it and started the transfer again ... and it worked.

Fail 6: Extruder 2 Stopped spinning again

After the firmware update to 6.2.2 it looked like the problem was solved ... A couple of prints worked fine ... but yesterday ... yet another failed print due to Extruder 2 not "spinning" ... what is courious to me .. it not even got picked up. So it shouldn't spin anyway, should it?

• Wasted time: 15h
• Wasted filament: 257g
• Wasted Energy: 2,8 kWh

As you can see in the fails above ... the problem also occured with the guide removed for testing.

Here you have the video snip: 2025.03.20_23.25_Extruder_not_Spinning

Prusa's only advantage here is, that there is NO alternative on the market (leave alone filament change systems which wast too much filament and prints take eternities ...) ... Otherwise I would have kicked my XL out of the window already.