Part cooling mod

I have tuned and tweaked, i have tested and tried, but no mater what i have done the overhangs i get are atrocious! well at least compared to what i’m used to. they remind me of the Ender 3 with stock cooling. i would like to try and upgrade the part cooling for the SM 2.0 but i’m not sure how i’m going to add anything to the existing print module. so i’m starting this thread looking for thoughts, ideas, suggestions, warnings, and any other advice you all can provide. ideally it will be something like the Bullseye mod in the end, but currently that is just wishful thinking.

thanks for the help,
-Atom

Do you use Luban for slicing your stuff?- With other slicers it is possible to reduce print speed per layer if it is printed in less than 15sec, for example.

Which filament and temperature you wanted to print?
Which speeds you wanted to print?
Show some pictures of your ugly overhangs pls!

Hi there,

What you are asking Atom is not an easy mod as not only mechanically is challenging, electrically also, as the fans are controlled through CAN bus so you have to make sure that what you connect don’t overload the fan electronics but let you control the speed ( unless you want to just connect to the 24V and keep the fan always on :slight_smile: ). As part of my hotend improvements, I have already been thinking about how to increase the part cooling capacity as it appealed to me too low and you just confirmed it.
I just have a mockup and design idea, unfortunately, which I still don’t have time neither printer to work on ( for a couple of weeks at least ).

This idea includes two of the fans I’ve already found as Alternative Hotend Cooling 2, which each provides 3.3 CFM and consume only 0.05A each ( the actual fan consumes 0.1A) so fit nicely in parallel and a redesign of the actual fan duct to fit them. The mockup looks like:


The horizontal fan is inside the printhead and is quite a tight fit. It has to be snapped into the duct from the side after removing the left cover and the electronics.


The Vertical fan is outside and also snapped in the duct to be easily removed as it blocks the access to the extruder and is good to keep easy access.

If we make it to work mechanically with a good duct design that fits, we can have a total of 6.6 CFM (vs 3.7CFM) and electrically compatible and firmware controllable fans.

If anybody is able to work in it from the mechanical point of view, I’m glad to help as I can (the good part to have an inactive printer is that is not a big deal to dismantle it to learn).

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I see the largest issue being mechanical, because electrically we can place power transistor between the CAN controller and the 24v source and use whatever fan we decide works best. But I often open the extruder door so I would hate to have it blocked.

Also are both those fans for part cooling? Or is the internal one for the heatblock?

Both fans are for part cooling, the one for the heatblock is a similar one located on the right of the printhead. So will have 3 fans in total. You can move the front fan leftwards to keep the path of the extruder free, will make the mechanical design a bit more challenging but doable.

My initial approach is trying to keep it as simple as possible and trying to make a clean mod, things will always get complex afterwards :slight_smile: and here the space and options without hard modifications is quite limited.

@Franky would you mind sharing your model for the bracket? I would like to give it a good looking at and maybe give it a go.

That would be nice, I’m interested too!!!

Dear all,

Sorry for the late reply, these are strange and busy times.

Unfortunately I do not have the design yet, I’m still setting up the final place where my 350 will sit and now is still to be set again. What I posted is just a mock-up, using the actual fan duct and the 2 alternative fans, just to check the feasibility and size. My mechanical skills are still limited and it will take a while for me still to address that as I’m now focused more in the Firmwares ( something I can do without the full 350) and hotend improvements ( I want to print PETG-CF and I need to go beyond 250 degrees which is really dangerous to do with PTFE as it starts to melt and generate dangerous fumes ).

I came across this design last night: https://www.thingiverse.com/thing:3205039

From an airflow perspective, it looks like rather than flaring the outlet, you’d want to constrict it, but the simple idea of a plate with an outlet nozzle seems to be a solid one.

@ITmaze, i think the SM2 has a pretty good looking duct on it. i’m not sure i could improve much with just a discharge head. maybe if i redesigned the entire duct i could achieve a lower duct static pressure? that is probably why that discharge head is flared, to reduce static pressure so that the little fan can push more air. i think the real issue is that it only moves 3.7CFM to start with.

@Franky i understand, i’m not even looking at the firmware until SM opens up the screen and MCU firmware. as far as the hotend is concerned, please post about your adventures, i would love to see an all metal hot end. in fact i’m almost thinking about scrapping the SM2 printhead all together, salvaging the MCU board and using it to build an entire new print head. then i wouldn’t have to worry so much about fans fitting (physically i mean) and put a nice volcano hotend on it.

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Have you seen this for the original?

Between that and the custom solder paste applicator people in the SM1 forums are working on, I’m hoping that can be brought into SM2, without having to scavenge parts.

Unfortunately that dose not work as well for 3d printing because of the high temps. You need a temp resistant frame to mount the hotend to. Once they release the high power laser and 3rd party spindle I could probably mill the parts though.

Finished my model, it’s posted here. Check it out if you’d like:

@brent113 thanks for all your help on this! It is an amazing mod you have made! Please keep adding to the forums as you have been the last couple weeks. We need more members like you!

-Atom

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Thank you so much for the kind words! I plan on it!

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