30mm blower fans sensitive to the hotend heat and stops working

[bmgoncu]

The BOM specified GDSTime 24v 30mm blower fans used for the Part cooling fans are susceptible to overheating from being in close proximity to the hotend.

Observed behaviour;

• When the hotend is hot the fan on the side of where the heater cartidge tip is visible, ossilates and doesnt spin
• When cooled down or when the hotend is not driven the fan spins as expected.
• The other part cooling fan spins normally.

Potential fixes;

• A not so temprature sensetive blower fan
• Somehow isolating the heat of the hotend from the fan hub.

Also asking for potential workarounds and/or solutions.

[bmgoncu]

İ have done some further testing with a makeshift heat shield and it does appear to alleviate the problem. Havent tested with the chamber closed and heated but i think this is a good start; Both of the videos are from the same test, at 240c one is at 5m in and the other 15m. After 30m i concluded the test since the heatshield reached an temprature equilbiliurum of around 50c-60c

https://youtube.com/shorts/RvsFIU7-kds?feature=share

https://youtu.be/qGwNJFiHI5k

[bmgoncu]

Added the shielding with vhb to the fan (not ideal i know) the issue presides albeit the fan transitions to that state later (might be a placebo effect havent occured to measure the time).

[bmgoncu]

More of the same issue i think; https://discord.com/channels/460117602945990666/696930677161197640/877269535609212939

https://discord.com/channels/460117602945990666/696930677161197640/875596876966158336

[pfmooney]

Yep, I've seen this as well. I even tried pushing the kickstart time up to 2s. In a warm chamber, even 30% was too low for them to stay spinning sometimes, whereas 20% was fine cold.

[Hexide]

I do share some common symptoms with other people i've seen on Voron Discord, including @bmgoncu:

• Fan works fine when everything is cold
• Fan maybe works for few layers if they are quick
• Fan does not work by the end of print

I have done one small test on my printer; wrapped heat block with kapton tape, to slightly insulate the exposed cartridge from the fan. This improved the situation, during the voron cube print, fan appears to be working for additional 5-10 layers when comparing to unwrapped heat block.

---

This led me to entire hotend teardown to see, what I could have done incorrectly during assembly, couple things were apparent.

When I was initially assembling my mosquito hotend, it came with screws which were suppose to hold heat cartridge and thermistor in place and won't allow them slide out. However, my cartridge was longer than the heat block and since I initially used the screw, it caused it heater to stick out on the side with failed fan.

This is how the hotend looked after removing it from the toolhead (minus the screw on side which suppose to hold cartridge and thermistor in place, i had already removed it) In the picture, heat spot is visible on the Cowling caused by the heater and the failed fan above it.

---

Few things I discovered after faulty blower teardown:

• Fan driver relies on rotor magnetic field, to be able to control coil polarity and drive the rotor
• Spring inside the fan always force rotor (as far as circlip allow) away from the driver
• Theory: Heat cycling COULD make rotor move microns further from the driver
• Magnetic field of the rotor DOES weaken with increased temperatures, therefore driver is unable to pick it up

Basic fan test mockup, with the spring removed and rotor slightly sticking out: https://www.youtube.com/watch?v=wZTfPYWvUoo

---

Few takeaways for me from this rebuild:

• Ensure heater is not protruding from the heat block
• Insulate side opposite to heater cartridge wires

Thoughts:

• Less sensitive or better design fans would probably be a good thing in this case.
• Silicone sock, which has hole only on one side would probably also be a good thing in mitigating this issue.

After the hotend rebuild with new fans and insulation, I've so far had printer working for ~30 hours, no signs of any issues. This makes me think, these minor changes were at least effective at delaying the problem (if not completely eliminating).

---

My choice for insulation materials:

• 1 layer of fiberglass tape (tesa Professional 60101 Fibreglass tape) - as air gap between fan body and aluminum foil
• 1 layer of aluminum tape (tesa Professional 63632 Alu-Tape Universal) - as infrared reflective surface

[pfmooney]

My choice for insulation materials:

* 1 layer of fiberglass tape (tesa Professional 60101 Fibreglass tape) - as air gap between fan body and aluminum foil

* 1 layer of aluminum tape (tesa Professional 63632 Alu-Tape Universal) - as infrared reflective surface

I've been meaning to try insulating the backs of the fans similarly (probably just Al foil and kapton). When I have the time, I'll report back with the results.

[Hexide]

My choice for insulation materials:

* 1 layer of fiberglass tape (tesa Professional 60101 Fibreglass tape) - as air gap between fan body and aluminum foil

* 1 layer of aluminum tape (tesa Professional 63632 Alu-Tape Universal) - as infrared reflective surface

I've been meaning to try insulating the backs of the fans similarly (probably just Al foil and kapton). When I have the time, I'll report back with the results.

In my case, kapton did not do much 3 layers of it barely improved the fan spin duration. I'd say just go with the alu-foil. The fiberglass I used probably has little-to-no effect, it just happened that those tapes were next to each other in store.

[pfmooney]

In my case, kapton did not do much 3 layers of it barely improved the fan spin duration. I'd say just go with the alu-foil. The fiberglass I used probably has little-to-no effect, it just happened that those tapes were next to each other in store.

I don't have any Al tape handy, so the kapton is to keep the foil in place.

[bmgoncu]

My 1-2mm sheet of aluminium reflector job did not do the job perfectly, my ptfe tape came in today, i will also ad that to the fan when my new fans come in. will report with the results

[pfmooney]

Al foil as a reflector does not appear to have helped at all. I swapped the fan on one side for one of my spares and did not seem to help either.

[lococnc]

Delta fans do not have this problem. My GDSTime fans lasted a day. Replaced and have no issues. Mine are 12v so it took adding a buck,

[pfmooney]

Delta fans do not have this problem. My GDSTime fans lasted a day. Replaced and have no issues. Mine are 12v so it took adding a buck,

That's for prints in a warm chamber, or in open air?

[lococnc]

Sealed Chamber, printing ABS, I run fans at 16%

[bmgoncu]

@lococnc Can you provide an aliexpress link so i can verify? Maybe the BOM may change if it is indeed superior.

Edit: Are these the one you used? https://www.aliexpress.com/item/1005001949622529.html

Edit 2: also what are your solutions for the 24v->12v problem, klipper settings or wiring configuration? Did you use the max power setting in the .cfg file? # #

[lococnc]

I bought from Digikey https://www.digikey.com/en/products/detail/delta-electronics/BFB0312HA-A116/5022815 I used a small buck-converter to power the + terminal on fan, since the MCU switches ground.

[blalor]

When talking fans, there’s little value in citing the brand or vendor as the sole detail. The DigiKey link is ideal. The useful info is in the specs, which are seldom provided on aliexpress, Amazon, etc. CFM, static pressure, voltage (obviously) and noise are all relevant.

[lococnc]

Ali link to one identical to the ones I used. https://www.aliexpress.com/item/1005003179503083.html?spm=a2g0o.productlist.0.0.74d52c3aBSuXD7&algo_pvid=c56dd7c2-b18e-4b14-8008-ffcd0abfa046&algo_exp_id=c56dd7c2-b18e-4b14-8008-ffcd0abfa046-1&pdp_ext_f=%7B%22sku_id%22%3A%2212000024528815771%22%7D

[Hexide]

Update on my insulation attempt:

After ~70 hours of printing, GDSTime fan started showing same failure symptoms. So issue was simply postponed rather than being fixed.

This calls for BOM fan to be changed to something that works better.

Personally, I will give a shot for listed Delta fan.

[bmgoncu]

I already ordered a set, will arrive in 2 weeks i think. Will update with results.

[xnaron]

@bmgoncu did the new fans work? I noticed the Delta fan linked above is 12V. Any issues with the airflow? I guess it is better than a non spinning gdstime one :)

[bmgoncu]

@xnaron yeah they totally do work, the airflow is signifocantly better (As it is the noise) and the best part no heat shielding at all (sorry for the radio scielence totally got carried away by other things and didnt report back)

[xnaron]

@bmgoncu Awesome thanks! Did you use a buck converter to get the 12V for them?

[bmgoncu]

Actually no, i use the split wire config described in the doc

[lococnc]

Buck it.

[aschiweck]

• Fan works fine when everything is cold
• Fan maybe works for few layers if they are quick
• Fan does not work by the end of print

I can confirm this issue also using a mosquito hotend.

I replaced the BOM specified GDSTime blower fans some time ago (>3 months) by ones from WINSINN, 30mm, Blower, 3010, Dual Ball Bearing, 24V. They are working smooth since then, regardless of heat or hotend state, no buck needed.

I bought them from AmazonDE but i think you can can get them also from https://winsinn.com/30mm-fan-raspberry-pi/ (3010 Blower - Dual Ball Bearing)

[szafran81]

Both links from sourcing guide redirect to GDSTime fans (just checked).

[Foofinator94]

I've recently been through about 6 of these fans, tried fan saver and this didn't help, and others on the Voron discord are still having issues with the fans on MiniSB. https://discord.com/channels/460117602945990666/461210576618651669/1066792849221357578 Even with its new fan-saving design.

I have had one GDstine that's done 500+ hours and another do 20 minutes, 2 hours, 5 hours, 50 hours... on fully heat-soaked prints.

An inconsistent quality supplier is not a good quality one, with all the evidence and issues... I suggest these fans be removed from the BOM and the 5V Delta fans become the go-to. They may be double+ the price, but if that means you use less than double the fans over time, I think that's a better sourcing decision especially for newcomers just wanting to print stuff, and forcing the kit suppliers to send the better fans.

I did find cracking the door open stopped the issue on one of my GDstine fans, with fan saver too, but resulted in chamber temps cold enough to warp ASA on larger parts, thus meaning I was limited to ABS+ and small parts only.

[szafran81]

My GDSTime did one Voron cube print, and after that they died each print after about 5mins. Now I use the WINSINN 24V 3010 ones, and they work great.

[porkcube]

Had GSTime 24V 3010 blowers on my 0.1, total failure of one in under 100hrs, replaced with Fabreeko upgrade kit and have almost 400hrs of them working fine since.

Separate new 0.2 build have been fighting the blowers, replaced right side 3 times before finally got a good cube out of ABS, then the left side started failing. Tried fansaver and non-fansaver mounts which made no difference, only opening the door allows for a decent print with ABS.

[Skystrike005]

I'm facing the same issue as well in miniSB and GDSTime fans. Fan saver + dragonfly BMO lead to dead fans when the chamber is at printing temp. Fans are brand new, less than 1 hour of printing time.

Will try replacing the fans with winsinn ones. Heard they're much more stable. If all fails i'll try using dragon burner with 4010 fans.