Findings and solution for the Snapmaker J1 clogging problem

Hello all,

this is a joint project by:
and the kind support of the Snapmaker J1 team.

Today we present you, our findings and solution against the clogging problem on the J1.

In this document you will find everything that leads to the problem and what it takes to solve it.

Document PDF, and converted here for viewing in the forum.

We thus hope to be able to offer everyone a solution.



Guys, a big hand for your analysis and fix! Outstanding! :sparkling_heart:

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Very nice work guys! If you want to modify my fanduct to fit to this hotend version, I’d be happy to share the step file. Just let me know. Cheers!

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This is great work. Will Snapmaker sell a retrofit kit or something for those of us not interested in the ultra-DIY aspect of printing and spent a good amount of money expecting not having to waste our time with this nonsense?

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That is something you need to ask Snapmaker Support.

But judging from the comments I read from you, I guess you clearly have bought the wrong printer.
If you do not want to do anything but print… things (I admit to have difficulties understanding what someone who obviously does not have any interest in DIY wants to do with a 3D printer at all) you should have bought one of the printers that explicitly have this claim: an Ultimaker maybe, a Formlabs Form 3 definitely - something like these, but not an “upper-range-budget-but-still-budget” IDEX printer like the J1.

I suggest to take a look at the price tags of those before ranting on about the money you spent on the J1. This is what “just print and forget anything else” costs.

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I hear you, and appreciate the work you are doing to try to fix this thing, but to say you don’t understand why someone would want to just print with a 3d printer that is advertised as unpack-and-go is a little weird.

I have a major interest in DIY. I have a 4x8 CNC router that I built, a mill that I converted to CNC, a CNC laser cutter that I built, multiple other 3d printers, some of which I built, a CNC lathe, and a workshop that would make Jay Leno jealous. If you’re looking for a DIY’er, I’m your dude. Other assumptions are incorrect and unfounded.

I just don’t like fucking with something that I paid a premium for with the expectation that it would work. I have the expectation that I will need to mess and tune a sub-$500 printer. This thing, not at all. It’s not anywhere near a price point I would tolerate bullshit from.


Okay, I never cared or even looked about how the J1 was advertised - maybe that is the reason for our different views.

But I stand to my view of the J1 still being a budget printer which (in the U.S.) probably ought to get a tag “some assembly required”.
From my point of view and looking at the competitors with the same functionality, I see a Tenlog TL-D3 Pro, Sovol SV04 and the likes as the cheapest chance to buy one, for about 500…600$, followed by a Flashforge Creator Pro 2 which costs about 700…900$ (i.e. almost the starter price of the J1). But all these are printers that IMHO cannot compete with the build quality of the J1. Then, there is nothing for quite a while, and then the real premium printers get into sight.

In order to charge the price they ultimately aim for, I agree with you: Snapmaker needs to get the printer to reliably print out of the box then. But with the ca. 1000$ it did cost initially, I expect some issues to be solved when comparing it with what the AFAIK only other IDEX printer in this range delivers.

Thus, I deem the hotend problem to be very bad luck indeed, and I would definitely appreciate if Snapmaker would send out replacement kits to the affected users. And I honestly believe they will test what we did now and do something about it since it inded affects the core functionality of the printer badly.

But I really do not think the price tag alone justifies a “plug and play” expectation when compared with what you can get for the same money (as noted above, without knowing the adertisements that were made) - especially when keeping in mind that there are quite some users that seem happy with it as it is, probably because they were lucky and chose the “right” filament.

Anyway, even with the hotend being fixed, my guess is the J1 is still not “plug and play” since it is highly advisable to invest some more time - in the slicer, for example.

Awesome Work. Thank you for that

What kind of heartbreak I can buy.
I saw some mk8 copperhead heartbreak on 3d Jake but im not sure that is the right one. I search on the spare parts in the shop.

On the upper part I have to build the distance thing from Alurohr and don’t use a Capricorn for that piece?

I will try that upgrades too and order some gears for the extruders too.

Kindly Regards and thanks for that awesome work you guys done here in this case

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The correct heatbreak is this one, for example: Bondtech MK8 Heat Break für Copperhead Hotends | IGO3D

Regarding the distance roll: That one has to survive an axial force of about 1kN (i.e. 100kg) on just 2…5 mm². This means a contact pressure of about 500N/mm² if you are unlucky. Sorry for forgetting the translation of the “Alurohr” word by the way, the word that should be there is “brass pipe”. I have sent an updated presentation to i3sven and asked him to replace that one. :slight_smile:

I do not know any printable plastic that survives this and does not creep.

Thus: yes, it is highly recommended to use metal, and I also suggest using brass. Brass is much easier to work than aluminium since it does not clog your drilling tool / file / sand paper, it is much more robust against the high contact pressure - and it will not damage the inside of your heat sink. “Aluminium on Aluminium” is never a good idea if the surfaces shall slide over each other at some point in their life.

Das korrekte Heatbreak ist zum Beispiel: Bondtech MK8 Heat Break für Copperhead Hotends | IGO3D

Zur Distanzrolle: Die muß eine Axialkraft von ca. 1kN (d.h. 100kg) auf nur 2…5 mm² aushalten. Das bedeutet eine Flächenpressung von etwa 500N/mm², wenn man Pech hat. Sorry nebenbei für die vergessene Übersetzung und Korrektur des Worts “Alurohr” - dort sollte “brass pipe” stehen. Ich habe i3sven eine aktualisierte Fassung geschickt, mit der Bitte, diese hier hochzuladen.

Also ich kenne keinen bedruckbaren Kunststoff, der das aushält und nicht kriecht.

Im Ergebnis rate ich DRINGEND dazu, Metall für die Distanzrolle zu nehmen, und ich mepfehle auch Messing. Warum? Messing ist erheblich einfacher zu bearbeiten als Aluminium, da es das Bohrwerkzeug / die Feile / das Schleifpapier nicht verstopft, es heält eine erheblich höhere Flächenpressung als Alu aus - und es beschädigt nicht das Innere des Kühlkörpers. “Alu auf Alu” ist nie eine gute Idee, wenn die Oberflächen irgendwann in ihrem Leben mal übereinander gleiten sollen.

Ach so - falls jemand das obige PDF auf Deutsch lesen möchte: Snapmaker J1 - Hotend-Fix - Snapmaker - 3D-Druck Forum


Thanks for the help, may be i try then Creality Spider Nozzles or V6 Nozzles. They are longer and i can use the 4020 Fanducts and their covers.

Hope that works :slight_smile:

The spider nozzle works, as noted in the PDF, it just reduces the choice of nozzle sizes you have. It might help though to get an M6 nut made out of copper, sand that down to about 4mm height and lock it against the heat block after tightening the nozzle to increase heat flow into the lower portion of the nozzle.

Thanks for all the work you’ve invested in finding the reason for the clogging issue. To me this looks like a fundamental design error in the J1 and I’m interested how Snapmaker will deal with this. In best case they develop a new hot end and offer it as a replacement for everyone. Second best would be to develop a new hotend for future sales but let deal current owners with a fix on their own. And worst case would be to ignore the issue and sell the J1 with the old hotend until eol.

I currently have additional hotends on backorder. Would you recommend to cancel my order until it becomes clear what route Snapmaker will go?

Btw. does your fix help in any way with the other widespread issue, the beating sound and resulting bad surface quality on vertical walls?

Regarding your hotend order, I am afraid you need to come to that conclusion yourself :slight_smile: We do not know what Snapmaker will do with our findings. If I were them I sure would do something since I would want the J1 to be a success, but it is up to them to decide if and what they will do when. For now, I guess the Snapmaker development will carefully read our data and try to confirm our test results.

I decided for myself that I want to have full use of the printer as soon as possible, therefore I invested a part of what I saved from being an early buyer into a full set of parts for all my hotends.

Regarding the beating sound, I am unsure what you mean: if you mean the “clack-clack” sound coming from the extruder: this will be solved by the improvement.

Apart from that, my J1 never produced any beating sounds - I guess this is since I lubricated its linear slides as the very first task upon its arrival and then let it run slowly until I was sure the grease was evenly distributed in the sliders. Therefore I am afraid I cannot help you with that…

I referred to the other thread " Help, terrible beating noise".
Following the journey of @i3sven it is not triggered by lacking lubrication nor bad linear rails as he still has this issue after replacing all linear rails. Last suspect was stepper motors running too hot but final confirmation still waiting for. So the reason is currently unknown.

Obviously this beating noise cannot be fixed by modifying the hotend but it could be the bad quality of vertical walls was in fact a secondary effect of the hotend issues and not primarily caused by the beating noise issue. But as you don’t see this issue on your J1 only @i3sven can answer this question.

Good morning,

Now that I’ve recalculated and tried, it’s possible to print spacer sleeves yourself.
With Polymaker Nylon CoPA 6/6-6, it’s possible, you just have to know your printer well and adjust the filament flow accordingly.
You also have to keep in mind not to overdo the counter!
Since the filament is very expensive, you should get some sample material so you can print some.
e.g. B. Filament Sample / Produktprobe 50 g - Filamentworld - Jetzt Kaufen

Then there’s the issue of noise.

I’m not entirely sure yet, but I think it’s coming from the motors, because after putting heatsinks on the motors I haven’t been able to find anything else so far.
This then indicates bad tolerances in the engine.
When I find new engines, I’ll take mine apart, I’m sure you should be able to find something there.

Moin zusammen,

nachdem ich jetzt mal nachgerechnet und versucht habe, ist es doch möglich Abstandshülsen selbst zu Drucken.
Mit Polymaker Nylon CoPA 6/6-6, ist es möglich, Ihr müsst nur euren Drucker gut kennen und dementsprechend den Filament-Fluss anpassen.
Dazu muss man auch im Hinterkopf behalten, das Kontern nicht zu übertreiben!
Da das Filament sehr teuer ist, solltet ihr euch Probematerial besorgen, damit könnt Ihr einige Drucken.
z. B. Filament Sample / Produktprobe 50 g - Filamentworld - Jetzt Kaufen

Dann das Thema Geräusche.

Ich bin noch nicht ganz sicher, aber ich denke, es kommt doch von den Motoren, denn nachdem ich Kühlkörper auf die Motoren gesetzt habe, konnte ich bis jetzt nichts weiter feststellen.
Das deutet dann auf schlechte Toleranzen im Motor hin.
Wenn ich neue Motoren finde, dann werde ich meine mal auseinander nehmen, da müsste man sicher etwas feststellen können.

Sleeve for the modification
Huelse für J1 umbauv2.step (7.0 KB)

The copper head is a bi metal, thought i try make me one. Damn it took me 3h to make this :rofl: i will make one more then test it :blush: