FYI: Snapmaker 2 All-Metal Hotend Simple Mod

Let me put some context. I want to use my 350 to print Carbon Reinforced PETG, in order to do that I have to be able to reach around 260 Degrees, a bit more if I have to use a hardened steel nozzle to manage the wear.

As you may know, PTFE starts to degrade and generate toxic fumes around 240-260 degrees. In the Snapmaker 2, we have a PTFE lined hotend, that means that there is a PTFE tube that gets up to the nozzle, thus I needed an all-metal hotend to avoid the problems of PTFE degradation.

In terms of nozzles, the Snapmaker 2 supports MK8 nozzles which are very common and easy to find in various types: brass, steel, hardened steel, titanium and copper plated. I’ve found one that looks especially interesting as it’s a copper-plated nozzle that can support carbon fibre , so I’m going to use this one as it improves thermal performance respect to brass and it’s close to hardened steel in terms of wear resistance, awesome :smiley:

Now the tough part, the heatbreak. The heatbreak on the Snapmaker 2 is a custom one, but after taking some measurements, I realized it has an M6 thread for the nozzle and a non-threaded 6 mm type on the heatsink side. This is also a size supported on the MK8 heatbreaks, but quite difficult to find. I’ve been able to find some steel heatbreaks which can be compatible ( titanium would be better but could not find the available in all metal ). I’ve ordered them and this how they look like besides the standard SnapMaker 2 heatbreak:

Mechanically speaking, they fit nicely and are fully compatible. The screw in the Snapmaker 2 heatblock and in the heatsink. This is how it looks with the copper-plated nozzle and the Snapmaker 2 heatblock:

And this is how it compares to the stock hotend:

And the final picture inside the Printhead :slight_smile:

The great question here is: how does it perform?
In order to test it, I’ve done some measurements, just changing the heatbreak ( so keeping the brass nozzle in both cases). I’ve attached 4 thermocouples to the hotend: 1 to the heatblock, 1 to the nozzle, 1 to the exterior of the heatbreak and one inside the heatbreak. I’ve also done the testing outside the printhead, so the works possible conditions. Then I’ve used :slight_smile:

  • M104 S100 - Set Temp at 100 Deg C
  • M105 - Read Temp from FW (This has variability as the thermistor can move around between tests, that’s why I also measure directly the temperature in the heat block and nozzle)

and wait 5 min after reaching the target temperature. The results are:

STOCK HOTEND

  • FW Temp: 100 Deg C
  • Heatblock: 108 Deg C
  • Nozzle: 105 Deg C
  • Heatbreak: Inside 62 Deg C / Outside 53 Deg C

so we have a delta T between heatblock and inside the heatbreak around 46 deg.

ALL-METAL HOTEND

  • FW Temp: 100 Deg C
  • Heatblock: 102 Deg C
  • Nozzle: 102 Deg C
  • Heatbreak: Inside 66 Deg C / Outside 54 Deg C

so we have a delta T between heatblock and inside the heatbreak around 36 deg, which is 10 Deg C worse than with PTFE, but comparable. In order to minimize the heat-creep, I would suggest to use a very good thermal paste on the heatbreak and heatsink interface. A very good one that hols up to 350 Deg C is Thermal Grizzly Kryonaut..

As soon as I can setup again my 350, I’ll try to do some testing and report back.

@Atom, I hope this is inline on what you were looking for :wink:

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That’s great stuff, thanks!

Holly mother of 3d printing! This is great!!! Thank you so much!!! I can’t belive you found something that fits inside the stock module, let alone do such extensive and thorough testing… maybe we should try upgrading the heat block fan? That should help with delta T and if we are upgrading fans it would be an easy change.

This is indeed awesome! I am working on mods/updates to my platform and this seems like a good one overall for not only just the specialized printing, but general heat transfer. On that related note, I’ve started to try a new nozzle with increased flow and heat transfer: https://www.th3dstudio.com/product/ezflow-nozzles-copper-nozzles-with-tough-plating/ Mostly for helping with printing TPU, but that helps in general.

Another thing to add to the list! :slight_smile:

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did you just eyeball the depth to install the throat? as the little flange on the stock throat is what locates into the module resulting in consistent nozzle height.

Also which interface are you suggesting we apply thermal paste to? Would you have an image?

Oh man, that’s awesome!

I work in a machine shop and I was thinking how cool it would be to come up with a replacement feeder gear for the print module out of some 4140 in order to be able to print more abrasive stuff without concerning about the wear on it.

It would be rather challenging, but there are some extrusions out there of gear stuck and its not impossible there is a stock someplace of a similar type of spur gear. We own several 4 ft lengths of a brass spur gear bar which we no longer implement into our product. At the very least I may be able to have some spares to change out, which would certainly come in handy .

I find it interesting that the temperature throughout the hot end is more consistent compared to the stock part and I could see how this might have a positive impact on your flow.

This is great stuff thanks for sharing!

Edit: Take note, I am quite an amateur at engineering. I do some at work but I am not educated, just a cowboy. The term Delta T that keeps getting mentioned is likely some very good reason why I’m wrong.

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Hi @C.Harris,

You can find a very nice overview on how to do it in this Teaching Teach video , including the depth of the throat. The only extra step I’d do is also add the thermal paste to the throat part that goes inside the heatsink to improve the cooling of it.

Let me know if that solves your questions :slight_smile:

Regards
Franky

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Thats perfect, thank you. Im sure i’ll figure out anything else that isnt immediately clear as im picturing it!

Hi, so it works? I have destroyed my heatbreak when I clean it. It was clocked with a bag ptfe filament who need to print near to 250°c.

So I search a new heat break, I want try one full métal to print carbon filament. Why replace all hot end when only a little parse is break…

I have seen mini pursa heatbreak is not a lot different of snapmarker.

A snapmaker 2 hotend assembly is like 9 bucks including heatbreak (and you should have gotten a spare with your shipment), but

yes there are ways to do this. yould just have to be careful to get everything assembled and calibrated in such a way that the top of the nozzle is going to be 1 mm from the prox sensor

i am probably going to try experimenting with this soon for the heck of it.

I don’t see the problem with proximity sensor, it don’t detect nozzle. And you init the z with the card at the end. Can explain you me?

I’m just saying if your heatbreak ends up making the nozzle stick out further, the prox sensor might not reach and it may crash.

Just want to make sure the tip of the nozzle is about where it belongs, thats all.

Oh yes, soory, I have understood, you are right :blush:

@Franky I’m curious how happy you are with the all-metal hot end a couple of months later. Any changes/suggestions you have for people looking to do this mod?

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is there any news regarding the changes made?

Could someone be able to explain to me where the thermal paste goes?
Thanks :slight_smile:

Step 14 from here. Obviously not the same heatbreak, but the location and purpose of the paste is the same.

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Thanks you so much.

I have ordered the nozzle and the heatbreack . i hope it wil work good. :slight_smile:

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Let me know how it works! I’m very interested in doing this when I branch beyond PLA!

Ditto - I’m curious how this is working out for others, might make a couple hot-ends myself.

I haven’t gone near the SM in almost two weeks . Spring seems to have hit and that means a lot of work that’s a bit higher priority than mucking about with a printer of plastic bits :wink:

I have changed my brass nozzle for a steel nozzle, the auto-calibration always plunges into the bed. I have adjusted the proximity sensor to be 1mm ‘above’ the nozzle tip as instructed in another post about stopping the nozzle from gouging the heat bed.
Is there a trick to getting the auto level working with a steel nozzle fitted? Or does the proximity sensor only work with bronze somehow?