3DP Part Cooling Fan 5015 Replacement for Gen 1 extruder

Put googly eyes on it. The fan I’m using responds to PWM to as low as 50.


@Atom yeah, in the end function beats form in such a machine. I suppose the “uglyness” is just that you have a nice metal housing and then something sticking to the outside that looks out of place… Don’t get me wrong - if it’s necessary, it’s necessary. That does not mean I like it from an aestethic point of view :slight_smile:

Good to hear - suppose I’ll follow your road. Thanks for sharing!

Could ‘bedazzle’ it too. A little bling is always a good thing.


O could modify my mod to enclose the fan, then paint it silver metal so it more closely matches?

Since I couldn’t find my pack of googly eyes I put a bird on it, also chrome for bling as suggested :laughing:

@Hauke I’ll send you a little bird for yours if you want :rofl:


Im interested in doing this mod. Forgive me but I do not understand the function of the diode that you soldered in parallel to the fan connector, please could you explain in laymens terms?

If I did not include the diode what would be the potential reprecussions? I ask because I have no idea where to get a diode from nor how I would solder it into a crimped connector.

I would definitely be interested in the .stl for your version of the fan mount with adjustable positioning! Also what length M2 hex bolts are you using to replace the shorter ones?

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I will shamelessly copy/paste from Wikipedia:

A flyback diode is a diode connected across an inductor used to eliminate flyback, which is the sudden voltage spike seen across an inductive load when its supply current is suddenly reduced or interrupted. It is used in circuits in which inductive loads are controlled by switches, and in switching power supplies and inverters.

If you omit the diode, it likely will be fine. It will put additional voltage stress on the switching mechanism that turns the fan on and modulates its speed when running at less than full power. This could lead to premature failure of the fan switching circuit, requiring soldering components on the PCB, something to be avoided, if at all possible.

I did not measure the absolute maximum voltage stress the fan can generate in-circuit, as designed. I measured relatively, compared to the factory provided smaller fan, in a simple circuit I was able to quickly mock up on the bench. In that quick test I found the larger fan can generate over 3x the voltage stress of the factory fan. I also found a typical signal diode can limit the voltage to comparable voltages as the original fan.

It’s a bit of a stretch, but if you assume the simple mock up is the same as the in circuit function, then the voltage stress of the new fan without the clamping diode is approximately 70% of the maximum rating of the switching mechanism.

This is why I said it’s “likely fine”. But without an apples-to-apples measurement, in circuit, it’s impossible to know for sure.

I suppose tonight I could take that measurement and see if that diode can safely be eliminated. Will update later, if I can do that.

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Thank you for that, that makes a lot more sense. Indeed putting uncessary stress on the switch mechanism is just asking for trouble.

I assume I could just solder the diode to the cables between the fan and the JST connector? I would simply then shrink wrap the diode to the cables. I feel like soldering to the connector itself might be a bit finicky.

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The new fan’s cable was long enough, you could even print a small box that mounts with tape on the side or top of the toolhead that contains the splice with the diode, and maybe even a small perfboard with the connections and diode mounted to it.

I like your idea of doing it inline in the cable. Make sure and leave enough length between the stripped areas of cable that there’s no chance of a short. I would probably use 3 separate heat shrinks:


I’m working on the redesign with adjustable fan mount, for my model the wire goes directly from the fan into the side of the box (it does not wrap around the top and into the box via the can connection like Brent’s). I’m also working on a super small perfboard splitter with diode that will fit inside the existing print box. When I am done I will have two versions. One where you use the original side with 10mm m2 screws. Or just the mod as the side with the original m2 screws.

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I put googly eyes on mine!
Did run into a few mishaps, breaking off a capacitor on the board because I unscrewed the 4 screws from the board and not the back 2. Soldered that back on. Troubleshot about 10 times until I realized the fan should only come on when printing after the first layer. :man_facepalming:
After all of that it works!
Thanks Brent and can’t wait to see yours Atom.


I love that! Hahahaha.

Was regretting my earlier remark on “ugliness”, but seeing what that set in motion… :slight_smile: I like!

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Great mod… i will get round to doing this too but mainly using the CNC and Laser at the moment as I have a number of other 3d printers. Could you post some pics of the actual realised benefits in printing as dont want to do it if its actually only marginal gains

For me, it really helps with bridging. Without it bridges cannot be printed. If you’re not having a specific issue that can be resolved by putting a fan next to the printer I wouldn’t work about doing the mod.

You read my mind with that diagram! Ive been having issues with significant curling of edges when printing overhangs so hope this mod will help to fix that. Ive had okay bridging performance through fiddling with bridge speeds and extrusion multiplier in Cura.

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Sorry I haven’t gotten my modifications to this mod done yet. I am still fighting SM on getting a replacement rail, so many of my projects are on hold :frowning:

Would it be possible to share your original file? I would be happy to make the adjustable modification myself, just gives a really good starting point!