I Fixed The Prusa XL's BIGGEST Flaw

[@ygk3d]

PSA: Grease the coupler pins on the front of each tool. It achieves the same result as the bump solution.

[@dverbeek84]

Your support straps are connected wrong. See the image how they should be connected. cdn.help.prusa3d.com/wp-content/uploads/2023/11/175ea4aa457dab9ce02054b8f6041343-1536x1152.jpg

[@cabotmathiasen2962]

I did the recalibration and greased the pins, but my third extruder still looks horrible. Does the bump solution add much time to the prints? Or is there another new way of fixing the issue?

[@lostandfoundplaces]

Grease... with the same grease used for lubricating the rods?

[@ygk3d]

@@lostandfoundplaces yes

[@ygk3d]

@@cabotmathiasen2962 adds a few seconds for each tool change. I’m not aware of any other solution besides ones to do with the lead screws. But if you’re only observing the banding with one tool that’s likely not the issue.

[@CyberCrist]

I just got my XL a few weeks ago, but haven't had time to put it together. I finally did that last week, but I can't calibrate the 5th dock because it's missing the dock pins. I watched your video and wondered if any of the extruders wiggle like your does, and I found that head #4 did. I pulled it off, completely disassembled the front piece where the print head attaches to. The top flat dock "pin/grab-oid"" was wiggly, which is why I took it apart. Once I got it apart, I found that the screw on the backside was tightened but it was at an angle, so even tight, the flat dock "pin" still wiggled. Pull both off, switched out the angled screw and poof, no more wiggle on the flat dock "pin/grab-oid" piece. Once both of those pieces were solid, I ran the calibration again, for dock 4 and it was solid, it does not wiggle when it is the active extruder. Hope this helps!

[@frollard]

This should be a top comment.

[@bobnedved1589]

In his case, it appears, if you look at 6:02 in the video, that he has installed the support straps for the electrical/PTFE bundle incorrectly. As a result, he is blocking the lower right docking pin... this is an assembly issue, and this "solution" is un-necessary had the printer been assembled correctly.

[@ZhakRyuu]

@@bobnedved1589 Thats not true, he just left them loosened during this shot. You can see they are installed correctly further in the video. Plus even if they warent it wouldnt affect the printer in this way

[@bobnedved1589]

@@ZhakRyuuDo you have an XL? You are incorrect. If you block the coupler pins, further, if you fail to even periodically lube them, it can cause this exact issue. Take a look at Prusa’s support articles.

[@raycos1961]

As a person who is about to receive their $4000 Prusa XL, I am very appreciative that you have put so much effort/expertise into solving this problem and sharing it with the world.

[@ygk3d]

Thank you! Hopefully your machine doesn't have this issue. My second unit seems to be fine, but at least it's an easy fix if it does.

[@RobertCowanDIY]

Hey Taylor, nice video. As someone that has a Prusa XL, I can say that you should have zero wobble between the extruder carrier and toolhead. I double-checked mine and they're rock solid without any rocking like you demonstrate. You came up with a good workaround, but its not fixing the issue. Double-check that everything is lined up and there's a solid connection between the two parts, it should not have any play at all.

[@ygk3d]

Hey Robert. Thanks for your comment. You make some great videos on the XL as well! My tools feel pretty solid when they’re in the right spot (although I can still move them side to side if I push hard enough, to overcome the magnets). It’s getting them there that seems to be hit and miss. I’ve redone the dock calibration multiple times, including fully removing them from the frame. Despite that, certain tools don’t engage properly when they’re picked, giving them the degree of freedom to shift slightly, from which point on they are stable. The issue is that this shift happens over the print. My solution ensures they’re in the correct position before the tool moves to the print. Perhaps there is an issue with my tool changing mechanism, but my machine was fully assembled from factory so it wouldn’t be user assembly error. I’m not the only one experiencing this banding phenomena so I felt it was worth reporting on and sharing the solution that worked for me. I’m open to being wrong, and finding a better way, but for now, it seems to have eliminated the issue.

[@RobertCowanDIY]

@@ygk3dThanks! So, the locking mechanism should fully constrain the toolhead, allowing for zero movement. I could make a short video to show you what's going on with mine. There might be a misalignment of some of the parts, but when mine are locked, they feel like a single solid part, there is NO shift at all. They are loose on the 'dock' (on the back of the machine), but this is to allow them a bit of compliance when picked up. But once picked up, it should be solid and repeatable. I would check to make sure the plastic holder (the thing screwed into the back of the rear rail) is properly engaged IN the rail channel. There's a boss that extrudes into the center rail channel and it needs quite a bit of force to lock in place. If that's not happening, it might be skewed sideways, causing this issue. But any amount of compliance in the toolhead carrier is bad and needs to be corrected.

[@Dsk001]

​​@@RobertCowanDIYI came to the comments to try and say the same thing but Robert explained it better than i ever could. One thing i noticed in your video when you were calibrating the tools after pressing in the top lock you pulled on the tool and then locked the second one. I think this might cause an issue as the printer locks both at the same time. Try calibrating and after placing the pickup you lock and not move it see if that helps get the proper lock when the printer does it on its own.

[@ulaB]

@@RobertCowanDIY The amount of force needed to mount the docks actually suprised me when I put my 5T together. I had an issue with the T1 sometimes not getting picked up, but being dropped. The XL noticed that and reported an error. It took me a few times to realize the dock wasn't fully locked into the rail. While tightening the first one, I noticed that some of the others were pretty solid, but I was still able to tighten their screws a little more.

[@TheSshyshak]

​​​@@RobertCowanDIY I second Robert on this observation and even left a comment in the 2 head instructions to this end. The bosses/keys that engage the extrusion fit very tight. IMHO, they are too tight for an M3 screw to provide adequate clamping force to fully seat. I utilized an extension arm to increase the torque to the wrench to get mine flush and even broke one of the included ball end wrenches. It should have been designed to be M5 or larger. That said, with the docks flush and square they lock in solid with none of the wobble you have demonstrated. It is clear Prusa has brought some real engineers on the design team to level up some of the more DIY aspects from the outgoing MK3 but with the XL, there are still a few practices carried forward from the old design ethos. Undersized M3 fasteners are one of those.

[@RS474]

Well done on finding the design issue with this printer. I hope Prusa can come up with a real solution 👍

[@obie224]

Prusa will handle this issue the same way they handled the banding issue on their mk3 - they'll tell you it's "normal behavior" for a 3d printer and stfu lol.

[@dirkhilleke2498]

Just tighten all screws. It is not a design problem.

[@Lemon-wk9ds]

​@@dirkhilleke2498Yeah, that's the type of solution you would expect from a 4000$, pre-assembled machine 👍.

[@JJiG]

@@Lemon-wk9ds its not fully pre assembled though.

[@Lemon-wk9ds]

@@JJiG From what I can see in the video, the problem is in the toolhead and the extruder, which are factory assembled whether you buy the printer semi or fully-assembled. The problem seems to be on Prusa's side. If loose screws were the cause, I would assume that there would be no need for a custom 3d part to fix it.

[@UncleJessy]

gah damn those prints looked surprisingly bad. Really happy that you were able to find a solution and hope others with multi tool heads see this. I now want to recheck my single toolhead XL to make sure there is nothing like this causing some of the layer banding im seeing in my prints

[@brisance]

Single toolhead does zero toolchanging so if Z banding occurs it's probably something else.

[@theamzngq]

My single head is showing the same signs, perhaps you could reply back if you find anything?

[@davidthompson9359]

@@brisance You can't park the single tool head?

[@brisance]

@@davidthompson9359 as of today, no you cannot because the single toolhead does not ship with a dock. Refer to the Prusa help documentation for a single toolhead. There is no dock, and you are required to secure the extruder to the toolchanger with screws.

[@zubrkabbi]

Wow. Like bashing your tv with a fist, but automated! What a time to be alive

[@ygk3d]

Great analogy 😂

[@nickmerkus]

Ran into the same issue designing my own tool changer. Getting a tool changer mechanism to be reliable is no joke. Ever since the announcement of the XL I've wanted to know how the force is created to pull the 3 locating pins into their locations. It seems that this force is not strong enough. A teardown of the carriage would be really interesting. Might even reveal a solution to fix this without a workaround.

[@frollard]

This. With precision mounting posts and a flat reference surface + mechanical advantage drawbar it should have microns of play, not millimeters. This is absurd.

[@alexsalchemy]

Looks to me like the tool changer isn't pulling the tools tightly enough onto the carriage. The alignment mechanism should constrain every degree of freedom perfectly, without needing to be jostled into place. Any way we could increase the tension of the tool changing latches?

[@GMichaelBridge]

if those 3 acorn nut looking things can be adjusted, that would effectively allow the lock tension to be adjusted.

[@rithiksawant]

I'm really glad you found a solution to Z-banding! But, I think you have a defective tool changer mechanism. I own a semi-assembled 5-tool printer and I just purposely did a crappy job of the dock position calibration and it still passed without any of the misalignment that you are seeing. I've been lucky to have perfect layers since I assembled the printer. You may want to reassemble your tool-grabber head, maybe that spring you install during assembly is caught on something? Just some ideas. Happy printing!

[@BaioWithMayo]

Saving this one for when I get my order in! Maybe because ive been living with an Ender 3 these fixes seem like a normal thing with a first generation product, but I also understand people who see the price tag and want a perfect working system out the box. I understand both sides, and at least with this one since ill be getting mine 1 whole year after the 1 tool day 1 orders, most of the kinks are worked out by pros like you! I expect prusa to send a check in the mail for your R&D work haha

[@ygk3d]

Haha thanks for watching and commenting. I totally agree with you. Hopefully yours is better out of the box!

[@geometerfpv2804]

An ender 3 is $100, not $5000....there are no "two sides", this printer is a disaster and everyone knows it. It's not an acceptable product at this price point.

[@obie224]

@@geometerfpv2804 EXACTLY. that's how delusional some of these Prusa stans are. Bambu was able to design and build an almost fool proof multicolor printing system and sell it for $1500 95% assembled and ready to print in 15 minutes. checking belt tension with a phone app ? Wtf, my bambu does that automatically before every single print. download models and tests to correct print problems ? Uh maybe if i wanted to tweak a profile, but that kind of trouble shooting is almost unheard of for a bambu printer. its a ridiculous joke that anyone would spend 5000 on a printer and expect anything LESS than full functionality out of the box.

[@BoostFiend_Bud]

Bambu is cheap because they are using the cloud to steal your information, I'll stick with Prusa because I trust they're not giving China my info@@obie224

[@hologos_]

@@obie224As a Bambu Lab printer owner, I still think Prusa XL and its tool changer is the way forward. A fool proof design would be nice so let's see what the future brings.

[@Ratheon1075]

$3500 for a machine you have to "fix"? And people are happy that there's a 'fix' because their machine is shipping soon? SMH After all the time it took to bring this machine to market you would think Prusa would have done some testing and corrected these problems in house. I just don't understand how some people can fanboy Prusa so hard, especially in todays 3D printer market. The only cool thing about this printer is tool changing. Everything else is outdated and there are issues with the one thing that makes this printer what it is. After seeing all the problems people are having and fixes the community is having to come up with I am so glad I made the decision not to buy one. If I wanted to "fix" a printer I would by an Ender 3. Oh wait those print pretty darn good out of the box for less than $300. I have been fed up with Prusa for some time now. The market has left them in the dust. I sold all of my MK3S and have moved on. I now have much better printers that I paid ALLOT less for. If we as a community are willing to just sit back and accept sub par printers what motivation do manufacturers have to do better. Prusa knows it has a fanbase and is taking advantage of them. Stop buying crap printers at inflated prices.

[@jasonmiller5956]

Good finding! FWIW, my 2-tool XL does not have any shake/play in the extruders when they are pickup up, pretty solid connection

[@ZURAD]

Seems like a serious error to not notice or fix in 3 years. Surprised at this. Great job!

[@knightsljx]

If you owned a Prusa, you would not be surprised. There was an error in PrusaSlicer that generates unnecessary infill that massively increased print times. Multiple issues raised by different people on the Github for YEARS before it was only very recently fixed. And that's among numerous problems I've run into. I did not experience any less work I had to do to get my MK3S+ working properly than my Ender 3. And it costs like 4, 5 times as much? My MK3S+ is the first and last Prusa printer I will touch.

[@brisance]

It's good that you found the solution to your problem. While it works, it isn't indicative of a "fundamental flaw" because not all XLs exhibit these issues. Each toolhead dock is held by a single captured screw and it can loosen over time, so that is something I would check first. Second, the Prusa help page on belt tensioning and alignment on their support pages has to be improved, especially the section on alignment. With the extruder mounted, there has to be NO PLAY between the toolchanger and the front of the Y-axis on both sides. There is a likelihood your XL exhibits some play here.

[@Dave_the_Dave]

Nice simple solution. It still seems like this should be a stop-gap to fix the real problem of the tools not properly seating.

[@oliverfong418]

Amazing work, I hope Prusa will give you a reasonable reward for solving such obvious flaw in their design. This is unacceptable for a product that costs this much and still required users to bug fix it.

[@ygk3d]

Thank you! Maybe a free roll of Prusament 😂

[@obie224]

THERE WILL BE NO REWARD !! ONLY PUNISHMENT FOR NSINUATING THE JOE PRUSA IS NOTY AN INFALLIBLE GOD AMONG MEN !!! ALL PRAISE PRUSA !!!!

[@centenary6618]

This is pretty shocking. Other toolchangers put in an enormous amount of effort into accurate and repeatable alignment of the toolheads. How can Prusa’s solution have so much slop in it? This wouldn’t be acceptable for any other toolchanger.

[@AndrewSink]

That's some serious detective work. Nice job!

[@ygk3d]

Thank you!

[@jakob.k_design]

Great error finding and problem solving, but shocking that Prusa did not realize this themselves. Considering that this comes down to a rather simple error and can be fixed in a simple way it is somewhat unbelievable that this did not com up during testing, even after all the delays.

[@PrintFarmer]

There’s no way they missed it. This came up in testing and they were behind so they knowingly shipped faulty printers anyway.

[@sagichnicht6748]

Wonderful. I knew that the XL was salvagable but I feel it encouraging that some of the major issues seem to have such simple solutions. It seems you also managed to optmise the stringing away as well, which is the other main quality issue.

[@HunterMayer]

I have a print friend woth these banding issues and one without. Im stoked to show them this video.

[@wilsistermans1118]

I use the same solution for several weeks now. The layer shifting is a quite common problem with printers that do tool changes. Some printers have a better solution to fix the printhead to the movement system (strong magnets with two or three pins that fall in a fixation hole). A homing sequence of the X and Y axis is often used to ensure the printhead in the right position. If the print head is connected less secure, a bump on one or two sides may be the solution to ensure the printhead is in exactly the position where it should be. I use bumbs on both the left and right side. It takes nearly three seconds per tool change, but for great results it is a small price. The wipe tower is a specific XL problem. It often comes lose mid print. I did not find a good solution for that, except using no wipe tower at all.

[@gpt10]

The solution to the wipe tower coming loose is to use he smooth sheet.

[@Arcadenut1]

I am doing more and more prints without the wipe tower and have had pretty good results. I have the brush mod that wipes the nozzles on change, so that might be why I'm having good luck with it.

[@gpt10]

@@Arcadenut1 are you seeing any gaps in the print? It would look like a small hole in the middle of the layer.

[@Arcadenut1]

@@gpt10 I haven't noticed anything. Do you have an example I can look at? I haven't done anything really complex or large yet with tool changing. The largest thing I did was also using Flex and PLA but they were the same color.

[@PanchoVilla-gl2sd]

Mine has same banding and same movement while head is catched like 5:38. that movement is due to nextruder pins (not dock pins), they can be moved slightly, this movement seems at first sight that can be fixed tightening pin fixation bolt (you must quit nozzle to get access to bolt) but they are tigh, if you disassembly one of them you will find that pins are designed to have some play, I think to allow small deviations while catch/uncatch), with a rubber seal between bolt and pin.

[@ygk3d]

I made that discovery too. A lot of people saying their tool heads are rock solid and don’t have the same play, but that is by design. What shouldn’t happen is the tool being picked at an angle, then moving during the print. After it finds its center position it’s at a stable point but you can still move it if you push hard enough. Did you try the bump block solution to see if that fixed your banding issue?

[@PanchoVilla-gl2sd]

@@ygk3d My banding is unaceptable for a 3.5K machine but no so visible like yours, It happens even printing a 1 color benchie, I did not try your bumper but i have moved nextruder manually when it is catched to force to move to "right" position (assuming it was at wrong position) but no change at printing, banding still there. This are the things I have tried, some are recommended by Prusa support, none of them solved problem. - Tried diferent filaments - Tried different toolhead (all have same problem) - Re-check belt tension and sides alignement. - Try 0.4 nozzle - Reinstall all docks agains and redo calibrations. - Add Grease to 3 short pins on nextruders. - Loose trapezoidal nuts, treaded rod inserts and motor screws (Also loose linear rail screws) and tight while bed is at opossite height (up/down). - Remove theaded rod superior bearings to check if they are bending threaded rod and transmiting some play to Z movement. -Checked also squareness of chasis, angles, threaded rods are parallel to linear rails, threaded rods planity. -Umount/check/mount carriage -Change printer place (to discard table vibration)

[@marsgizmo]

great finding and solution! 👏

[@ygk3d]

Thank you! Love your videos!

[@GizmoTheGreen]

can't believe such a flaw wasn't caught and shipped... wow. good work getting to the bottom of it!

[@obie224]

They knew. The XL is the most overdesigned, overthought, micromanaged design for a 3d printer EVER. They just panicked and rushed the release because Bambu showed up and said "OH HEY JOE, NICE MARKET SHARE YOU HAVE THERE, MIND IF WE TAKE THAT OVER FOR YA ? K THANKS BYYYYYE."

[@ulaB]

@@obie224 I love how you are trolling the comments. Good job.

[@chronokoks]

@@obie224 Over-designed, over-thought???? What? They only panicked with the MK4 - XL has been on preorder since NOV 2021!!!!! Many of the promised features are not there like that stupid cycloidal gear extruder... Joe is FKKED, popularity got into his head and can't manage the company anymore.. it's too much of a task for him

[@AndrewMakowski]

i hope you shared this with prusa. Still waiting for my order. Also creator Teaching Tech has a video where he added some brushes to the tools and it also seemed to help.

[@quadraturencoder]

Oooh, thank you! I have the same issue and I have a great feeling that it will be fixed tomorrow after your bumper is installed!

[@filanfyretracker]

the three pins on the docking side of the toolhead, well more like bolts I guess, one suggestion I saw is a bit of super lube or similar on them so they slide fully into the carriage easily. Not the two big chonker pins that actually get grabbed but the more brass colored bolts. one on top two on the bottom.

[@DJProPlusMax]

Great! But it is a bit disappointing that a very expensive printer needs this…

[@falxonPSN]

Yup.

[@xXKisskerXx]

very much so. I mean, even if you only went with a 2 or 3 head design, the printer cost is freakishly high - to have this level of error. That is not to say it isn't valued properly - as tool head changing is a very intense operation - and you don't see others doing it - because of the cost associated and the now obvious precision needed.

[@DJProPlusMax]

Should I also mention that Martin Zeman 3D had the MK4 and XL in front of his eyes 4 years ago with Jo Prusa himself and said in his review of the MK4 that “it looks almost identical compared to from 4 years ago”?

[@TGWMS]

i just calibrated my XL´s and they work perfectly i have no issue with wobling like you. all 5 tools on 3 printers are totally perfect and prints are awesome.

[@SebastienChedalBornu]

this is nuts.... i have a home made tool changer system and never had this problem (it looks more like the e3d one but with magnets for holding the tool. congrats for the finding and solution

[@fouzaialaa7962]

i think the bump block should be in tpu , also stack this with teaching tech ideas and lets see what comes out

[@woutervossebeld4664]

The toolhead does not even have to move to get uneven layers, it if the tool isn't perfectly paralel the nozzle isn't in the position that it should be so the layers wont stack nicely

[@filetdelumiere5037]

Very well done investigation on this problem. I think you have discovered a main issue on the tool changer system ! As other comments say, I think this could never happen on such an expensive printer! Prusa has to improve and make a new version of this tool changer mechanism imo...

[@L.-tr7kk]

I was having a similar problems on my XL and found that the Nextruder dock was not level in the vertical position. So I loosed the Nextruder dock from the back (not the calibration adjustment the screw that attaches it to the extrusion bar) and adjusted it using a level and after re calibrating the docks the problem was solved.

[@jjs7898]

Good ideas/steps to your solution! I'll revisit this vid when I upgrade to a full 5 toolheads on my XL! From the video I do want to question one thing: are you using a textured sheet to print PLA? I ask because while I love using textured on my mini and have it dialed in just right, I noticed that on my XL it caused layer adhesion failures later on prints with PLA. I think it just doesn't do hot enough or squished enough to properly work with the auto first layer of the XL - I had to switch to the non-textured bed for PLA and good adhesion. Thanks for putting out these ideas in case I run into this issue in the future! Seems like I lucked out as my XL only has the worse version of this - a layer shift causing a print failure in rare cases, but also frequent crashes detected if I turn detection on.

[@ygk3d]

Thanks for watching. I’ve noticed the same: Prusa’s textured PEI doesn’t work very well with PLA. I experienced the same on my MK3 as well. Any other textured PEI sheet is fine for PLA but Prusa’s version doesn’t work. For that reason I prefer to use the satin sheet. It works occasionally for smaller prints like demonstrated here but I wouldn’t trust it on a long, full bed print.

[@obie224]

Imagine spending thousands and thousands of dollars on a "top of the line" 3d printer and having all these issues and problems that you have to figure out how to fix on your own. And most people would have ZERO chance of actually figuring this mess out, you have to be very knowledgeable like this guy. It's a crying shame how far Prusa has fallen from their glory days.

[@Arcadenut1]

It's like owning a Jaguar....

[@avejst]

Great video as always 👍 Love the simple solution for the toolchange. Great work 👍😀

[@JeffBradway]

I would love to see some more video and details on the tool change mechanism itself and how it locates.

[@Arcadenut1]

I haven't had the banding issues like you, but I'm dealing with other Docking Issues (self-inflicted to a degree). The way the docks are mounted is really a bad design by Prusa. Super tight tolerances for mounting and only securing with a single screw. The changing of tools is pretty violent and in my case it causes the docks to shift a little bit causing failures. I think if they slowed the tool changes down a bit it might also help your issue and mine.

[@nbalagopal]

Troubleshooting 3d printer issues are hard and I hope you get compensated for your valuable findings some how. Prusa should've found this themselves. Nice work! 🎉

[@ygk3d]

Thank you!

[@Leo-yh1lj]

Did you report this also to Prusa? Very interesting and will (well, hopefully not ofc) be helpfull when i finally can upgrade to a 5 toolhead version

[@falxonPSN]

Thank goodness for people like you! Mine will ship soon, and it's good to see it's at least possible to work around the bad engineering here. I specifically picked the XL as my first ever 3D printer, because I didn't want to have to futz around with all of the same stuff I would have to on a Chinese printer. It's somewhat ironic that Bambu Lab has become the hands off standard now even if they have all kinds of security and privacy concerns.

[@enterone801]

Those can be fixed with some simple firewall protection, like not allowing it to have any internet access.

[@osimmac]

all i gotta say is... WOW. can't believe prusa shipped it like a flaw like this. you did an amazing job at isolating the issue and solving it with the least amount of change. kudos to you for that!

[@barrag3463]

A trick I use on the MMU2S for issues with tower stability, especially when using different materials (PLA & BVOH) is to "encase" the transition tower in a separate object made of 1 material. It was designed like a "hat" with the "brim" on the plate, with me resizing the object to fit the tower after an initial slice. It's jank and is far from perfect since you're using more of one material, but it eliminated the issue of the tower coming loose from the plate or delaminating mid print.

[@KoenKooi]

Like a draft shield?

[@barrag3463]

@@KoenKooino. Solid Object (well, an object with 10-15% infill). Which is why it works well and why it's jank- jank because the printer is printing infill and the wipe tower over each other in the same layer, but works well because that infill, being attached to a solid object made of a single material, does not allow the tower layers to come loose at all. A draft shield would still have the potential to let the tower delaminate and "fall over" inside, although it may contain the tower and wiped material (although a sufficiently "tight" draft shield with 2-3 walls may have a similar end result to a solid object).

[@suntoxx9667]

Nice finding! This is something that Josef Prusa should comment on.

[@rendez2k]

I don't get whats going on at Prusa. Why is this stuff not being picked up in house during testing? One reason they are pricey is because you expect quality but that seems to be lacking recently? But great video and well done for fixing!

[@robh.8214]

Genius! Dang, so simple but so complex…. Well done!!!

[@ygk3d]

Thank you 🙏

[@caraqal]

I noticed in the video you have multiple of the plastic wire harness stiffeners mounted wrong on multiple extruder heads. You have to pull them up and get the screw shaft into the narrow part of the keyhole. Sadly I do not remember in what video i saw this issue, but when the plastic bands are fixed incorrectly they are too low and so the ends that are sitting too low might cause interference with the carrier.

[@ygk3d]

Thanks! This was an old clip I reused from a previous video. I have since fixed that.

[@anthonyzdavis]

Hmm...I wonder if that web app you mentioned at 03:57 could be helpful when controlling the belts of other printers (I have a Kingroon and an Anycubic) 🤔 What do you think?

[@ygk3d]

There are similar apps available that can show the frequency response of your belts. The Prusa one seemed to work well though. I don’t see any reason why you couldn’t use it for other printers.

[@anthonyzdavis]

@@ygk3d that's good to know. It might come in handy for both my current printers and the custom-built one I'm working on 🙂

[@lavafree]

Great work 👏🏻 at the same time it’s a pity how low quality testing has gone over at prusa

[@JustAnotherBigby]

I would guess this was time-pressure from Bambu Labs competition. To be fair, i was never able to get rid of layer banding in either of my Mk3's...

[@geometerfpv2804]

​@@JustAnotherBigbyTime pressure? Prusa has literally had decades...were they doing nothing that whole time? And now Bambu Lab has *another* printer while Prusa still can't make their work? Prusa held back this release over and over and over...presumably to make it perfect, right? Guess not. There is no end to the excuses for this company. I think they have a spoiled company culture. I think Josef is a control-freak.

[@LilApe]

@@geometerfpv2804 Remind me again now many warped build plates bambu had? Or how many broken AMS units? Or how many broken MC fans and broken AP/TH boards? They're on like revision 9 of their AP board lol. Lets not pretend like BL is the beacon of quality.

[@obie224]

@@JustAnotherBigby after the response of "tough shit it's normal everyone shut up about it" that Prusa gave everyone concerning the mk3 banding, i'm shocked that anyone is surprised by how shoddy and rushed the XL turned out to be.

[@obie224]

@@geometerfpv2804 BINGO !

[@75keg75]

6:08 As the tool when anchored to the gantry changer thingy is moving around that’s a big issue and probably is worthwhile Prusa modifying the tool head to have an in built shim to ensure the tension is correct and there is no wobble. A 3 point adjustment screw not unlike a build plate would be good as you can fine adjust it. I thought the clamp locked the tool to the gantry? Is it not strong/ tight enough? How long does your 2 lines of g-code added to 5 tool head print? Ie with and without? Is it any different to the fast move the 3d print dogs developed that Robert Cowan and tada 3d printing tried? I’m seriously considering dropping the xl mk1 order and waiting for a mk 2….

[@tEdDynOoN]

Great solution for a complex problem. Still waiting on mine, but more confident now watching this video. Thanks! :-)

[@ygk3d]

Thanks! 😄

[@gaveintothedarkness]

Excellent diagnosis and trouble shooting!

[@ygk3d]

Thank you!

[@SidekickElements]

it looks like the root cause is some issue with the sliding latch applying a non perpindicular force to pull the tool against the carriage. If that force is always perpindicular then the kinematic coupling should auto align repeatably like it's supposed to.

[@paulhuckaby]

An update on the XL would be a great video

[@DidgetTheFidget]

I’m curious if there is a cause. Mine doesn’t have this issue and the heads repeat fine

[@ulaB]

I do wonder if the docks aren't seated fully. I had issues with one of mine and noticed I hadn't tightened the mounting screw fully enough to squeeze the dock into the extrusion.

[@herbinio]

this makes the daksh v2 look even better

[@JasonEdelman66]

good find/idea.. but just wondering @5:59 the plastic extruder support strips are not installed correctly? (was this clip pulled from your previous video?) Happy XL'ing..

[@ygk3d]

Ah, yes. Good catch. That was old footage. I’ve fixed them since then.

[@Average3djoe]

How did you resolve tool change ? Can you explain mee in depth please ?

[@RojoNinja]

Out of curiosity, have you ensured that your docks are fully seated and tightened into the aluminum extrusion? It took quite a bit of wiggling to get mine flush. There are some forum posts about it, I would link but it made my comment get deleted.

[@ygk3d]

Yes. I've uninstalled and re-installed them multiple times. I don't like the single screw design for mounting them.

[@Hermy21]

you make a good point, those docks took some work to get full seated. I can see how this would cause an issue.

[@GMichaelBridge]

looks like the 3 points of the maxwell kinematic mount aren't being fully engaged if the toolhead is 'floppy' when attached, can you adjust the 3 acorn nut looking things to tighten up the engagement when the toolhead is locked?

[@knightsljx]

6:28 basically there is a massive design flaw where the tool head dock is only supported on ONE side on a machine that requires a high degree of precision to work properly

[@ThePrintHouse]

Dude Im absolutely blown away by this problem and solution. Solid investigation. Good job

[@ygk3d]

Thank you my friend 🙏

[@GuyH77]

I've been waiting for this video. great work. I need to run the test print on mine and see what the results are. I've only run some small multi-colour prints so far. I'll report back. How much time per change does the bump solution add?

[@ygk3d]

Thanks! Maybe 2-3 seconds per change.

[@GuyH77]

@@ygk3d Thanks. Just a thought, what about the nozzle offset calibration. One assumes that it has to pick up each tool 'perfectly' to get the correct offset else if not the 'wrong' offset will be set in the tool settings. I guess your testing shows accurate tool alignments as well. I may knock up a test print for this if needed.

[@ygk3d]

@@GuyH77 I redid that a few times over the course of my troubleshooting. It didn’t help unfortunately. I forgot to mention that in the video.

[@MrUntermieter]

Great investigation & convincing video - but how the h..k can it be okay for a multi-toolhead-printer when toolheads are not in a perfectly tight fit before restarting the print?

[@supercurioTube]

Incredible analysis and creative workarounds, and equally incredible flawed design and implementation by Prusa 🤯

[@uiopuiop3472]

i am the thead., i will force PRUSA to repair then printers...

[@zebarzebra]

It is literally the best design by far on the market. Not perfect sure, but you makes pretty you do not know what you are talking about.

[@supercurioTube]

@@zebarzebra "literally the best design by far on the market", I'm not sure what you're referring to since the results speak for themselves. As counterpoint, Teaching Tech's video illustrated that the XL design is lacking nozzle brushes, an effective solution adopted in many other multicolor or multi-material printers and which addressed some issues once added to the XL.

[@osimmac]

i would rather have filament wasted poops rather than horrible layer misaligned prints that end up in the trash bc they do not fit or look good @@zebarzebra

[@borisbommen]

The funny thing is its done by reduce filament waste but the execution is so bad its actually more. I hope it gets better soon, i like prusa but this is not good.

[@goldfingerdash]

You should contact Prusa, show them your video, and see what they have to say. I get that this has significantly improved your issues, but it needs to be fixed in the docking area. Your solution may wear the clamping mechanism over time. Did you try to bias the docked heads in the -Y direction before tightening, or make sure the Y gantry isn't hitting some type of premature end stop? There definitely seems to be too much rotation about the Z axis when tight.

[@mattmcpherson353]

I suspect you are correct on the wear and tear on the tool head but using this method, even for a short period of time, will be a valuable troubleshooting method.

[@goldfingerdash]

I made this comment before having my machine. I have it now and have printed these towers. My alignment is near perfect and mine have no wobble. I was also able to look at the design closer. The dock calibration only has to be close, it doesn't have to be perfect. The locking mechanism will pull the print head in just a little bit when it locks. I'd really be looking at that tool changer closely.

[@elchavode6479]

So i did print some ting tall with tool changes and i have banding and 1 mm shift but i was able to solve it with out using your mod by making sure the tool head dock where on super tight where they dont have any movement and sloved my issue.

[@janschaller5683]

I was so hyped for this printer and now i am disappointed. Hope the fix all the issues soon, so i can buy my 5 tool XL. In a world with Bambulab thats not accaptable from our loved company Prusa. Things like that ruins their reputition.

[@HunterMayer]

I wonder if bouncing around a shippnng container on its way to destination plays a role in this 'feature'? If I understood the solution: you're recalibrating that axis edge every tool change. But really what your doing is calibrating the printer to the new tool head? Or is the printer aligning tool head to the printer? I think the latter is more the case. Which made me wonder if any other tool head changing machines do a post change toolhead alignment check (PCTAC)? This corrects for a particular machines peculiarities at the time of the tool change once per change... And even small machine deviation that might develop over time (or a distance roughly shipped) get washed away... Forgiving a number of machine build sins... Neat find, thanks for sharing!

[@nilsirrah7672]

It’s insane how content creators can solve issues that companies couldn’t or refuse to. Either they are tunnel visioning or are in too deep to make the changes, it affects the customer base immensely. For 4k and still having issues it’s kind of unacceptable in my opinion. If you aren’t planning on using multi material for supports there is almost no reason to get the xl instead of the p1p. And if you need a large format printer u might as well just self source a voron for the amount of work you need to fix the xl anyways

[@cybernetix86]

Good job, it's not great you had to find a fix on a printer that costs as much. You might want to try to add some sort of brush under the pump to clean the nozzle at the same time it bumps the thing. I'm really disapointed at Prusa for dropping the ball like that.

[@enricovr83]

Have you talk to PRUSA about this issue? Your solution looks great, maybe they can use it. you should share with them. Great job!!

[@ygk3d]

Thank you! Haven’t talked with Prusa yet, no.

[@bluerider0988]

Nice temporary fix. Prusa needs to address this in the design. The tool heads must lock in place on the dock and on the gantry without any play, or else you'll never have any precision in your parts. I don't want to use this to print figurines, i want to use it as a tool to print functional parts which means it needs to be accurate. Bumping the tool head is not accurate.....

[@obie224]

NO JOE NEVER MAKES MISTAKES HE IS GOD. NOW SHUTUP AND GIVE YOUR $5000 TO JOE AND BE GRATEFUL FOR WHATEVER HE GIVES YOU.

[@2thlesswithta2s2]

Is Prusa getting this feedback? I appreciate your work-around, but they need to integrate a solution in the design.

[@ManWhoLostTooth]

You made it cost less than a decent used car?

[@CoernelSkateboarding]

I've always wondered that a Lathe part, with thread precise part should be!? I'm talking about the three recording pins.

[@narwhalking2788]

More people need to see this.

[@xXKisskerXx]

I wonder if there would be a way to improve this -to require less movement. (as multiple tool changes and each one now requiring a long move to bump block takes up MUCH more time) - like a flexible shroud around the tool head it can 'bump' into on the way out of the docking system, to do the same thing - but not require the extra movement?

[@rickyneeter69]

Bambulab got same problem?

[@FilamentFrenzy]

Hey, cool video, forcing the coupling like that will help but it’s not the best idea in the long run, simple fix is clean the 3 locator pins on each tool, also clean the 6 pins in the tool changing mechanism then lube the 3 locator pins on each tool should achieve the same results and will be better for the machine long term, subbed 🙌

[@falxonPSN]

Very good point. If it's just a matter of friction between the tool changing bracket and the pins, then a small amount of lightweight machine oil should solve the problem. This is definitely be with experimenting on. The key would be a very small amount because you don't want to end up with oil dripping everywhere or getting somewhere it shouldn't. An alternate approach would be using some kind of dry lube that basically leaves a Teflon like coating on the surface that is somewhat harder and resistant to scratching off. Now that I think about it, that might be the perfect answer here. The trick would be disassembling the tool head enough to get those parts out somewhere where they could be sprayed safely away from the machine.

[@ygk3d]

Thanks! Not sure what there would be to clean on those but I’ll have a look. You’ve showcased some of the most amazing prints on the XL.

[@nobodytoyou4887]

So let me get this right, Pursa made a tool changer , but didn't think to design the docking parts to constrain in all 3 axis? how the hell did they think was a good idea much less charge that kind of money. All they had to do was add a third prong to the docks for the draw bar to attach so it has a triangle to align with instead of a line which allows wobble.

[@elchavode6479]

I havent expeince it yet but i havent printed any tall yet

[@mattmcpherson353]

Add a head brush and a catch basin to that area and you will have the perfect upgrade.

[@ygk3d]

Those are on my list!

[@user-lx9jm1wo3h]

They should send you a ton of free filament for all the wasted prints you went through.

[@ameliabuns4058]

Damn tho that tool lock is not stable at all, very wobbly... maybe they should've used stronger springs etc.. I'm making a tool changer and i was gonna go with this mechanism but after seeing this i might just make my own with a motor. my doot changer "motorized" barely cared about alignment it'd just sorta self align itself after picking the tools up, unless it was really bad shame that you have to do this on your own on a 3.5k printer. to speed this up maybe try shaking the print head instead of bumping it!

[@klickeldiklick]

Great video, but one question remains: Where were the internal and external alpha and beta testers? Why are you the beta tester and the solution developer? This is a problem that every youtuber with multi toolhead Prusa XL has. I hate Bambu Labs for ther company philosophy (closed source, cloud, etc.) but for beginners and for people who need a reliable machine, the choice is way to easy.

[@Keptains]

Im really disapointed, i wanted to buy a RatRig Printer. Then saw the XL beeing announced and shipped soon. Preordered and they said it should arrive in Q3. I still couldnt make my order. Seeing all of these issues make me consider to buy a completly different printer at all.. I want to support Prusa and believe in their work but they take so long with anything when it comes to the XL. Im done tinkering with my Anycubic i3 Mega, i was hoping the XL to be a Carbonfiber/Nylon workhorse for me which i can rely on.. It makes me sad. I was keeping an eye on the market for the last 3-4 to buy "The next big printer" but im not sure anymore what to do

[@theamzngq]

Even though I have a single head XL, I am seeing the same kinds of layer banding and inconsistencies. Could something loose in the tool head be my issue also?

[@ygk3d]

mhh.. I’m not sure. For me the issue only occurs when tool changing.

[@spock81]

Great investigation!

[@kennethshrum7939]

Great detective work! I have a 5 head XL on order I have considered canceling and going with Bambu X1 Carbon, but I would prefer to stick with Prusa because of open source, support, etc.. I am still very concerned about stringing and blobs/artifacts. Thanks for your effort.

[@lap87]

"open source" not so much anymore.

[@BeefIngot]

You know, people say o0en source but I encourage you to look into it. In my opinion Prusa is open source mostly in name. They are forced to be open woth marlin and prusa slicer by the licesnes of the software they are based off of. For their hardware though, where are the files? They are less open than they claim to be. Thats something Ive been thinking about more, and increasingly annoyed by.

[@enterone801]

@@BeefIngot Prusa has a freaking tattoo of the open source hardware logo, so that is some serious bullshit if they're not. I'd be curious to hear their response if you asked for them.

[@BeefIngot]

@@enterone801 Bro people have asked for a while. They even somewhat recently had a blog post which had a pretty negative outlook on open source. That he chooses to use it as marketting is n9 proof he walks the walk.

[@AMakerDad]

Kinematic mounts such as those used on the Jubilee, E3D or PrusaXL tool changers are capable of micron level repeatability on coupling / decoupling. If your tools aren't seated well enough that they rock like that, there is something wrong with the assembly of your printer / tool changer. You might want to take a closer look at your dock setup and alignment instead of just whacking each tool on tool change. That being said, thanks for creating / sharing the stacked cube printing tests.

[@joshcarter-com]

Just got my XL-5 a few days ago and built it. I’m not seeing this problem at all. Tool lock-up is solid and there’s no Z banding on my prints. I’m wondering if you need to load latest firmware (5.1.2 I think) and redo the dock calibration sequence. It’s a pain in the butt, but it seems to work 100% afterward.

[@lucase764]

I guess I expected this printer to work perfectly out of the box.

[@chronokoks]

Holy shit that's crazy. How could they have made such an error? The Prusa team must be a complete mess.. how much are they paying those guys? Are those high-school level employees?

[@BobMuir100]

Entertaining as I don’t own a printer so informative was always going to be a push!!! 😊 Bob England

[@rufustoad1]

Can you teach us how you got such good support removal and good looking undersides after removal? Time 3:46

[@ygk3d]

PETG support for PLA. Zero gap (soluble support settings).

[@rufustoad1]

@@ygk3d OUCH I wish I had thought of that earlier but I am still learning. Thank you for the great input.