Replacement print fan options  

RE: Replacement print fan options

Printed Solid no longer has the 12v blower.

There are many 12v 50x50x15 blowers on Amazon, at 6000 rpm , but a couple at 5500. Of course the connectors are wrong and the wires too short, and the infamous Amazon quality, but if you need a blower now until the right one arrives...

RE: Replacement print fan options

The fans on the MK2.5(s) and MK3(s)(+) are all 5V fans driven directly from the ATMEGA2560's output pins.  Using 12v or 24v fans can cause problems.

As others have pointed out, I made a boo boo.  Please ignore this post!

RE: Replacement print fan options

Posted by: @ryan-f15

I am trying to replace the factory Prusa print fan but so far all of the ones that I have found have been the wrong rpm.  Is there a US source for a 5000 rpm radial fan? 

You can find a replacement here, for example:

https://www.printedsolid.com/products/ldo-5015-5v-blower-fan-df5015h05s

https://www.ebay.com/itm/LDO-parts-cooling-fan-Prusa-i3-MK2-5-MK3-MK3s-5v-3-wire-5015-Zaribo-Bear-Upgrade-/324403830807

https://www.globalsources.com/si/AS/LDO-MOTORS/6008840349362/pdtl/5V-blower-fans-with-wire-connector/1172693245.htm

(5V, speeds between 4500 and 5000 rpm)

RE: Replacement print fan options

@3delight

My printer has 12v fans.  I bought it a couple years ago.  I was recommended a 6500rpm fan and it's causing runaway hence the need for another fan.  Is there any indication as to when the official one comes back?

RE: Replacement print fan options

@karl-herbert

My fan only has 2 wires though.  I think it's 12 volts as well.

RE: Replacement print fan options

Posted by: @3delight

The fans on the MK2.5(s) and MK3(s)(+) are all 5V fans driven directly from the ATMEGA2560's output pins.  Using 12v or 24v fans can cause problems.

Please check before posting!

The MK 2.5 and 2.5S does use a 5v 3-wire fan for the hotend, but retains the 2-wire 12v fan for the parts cooling fan. The MK3, 3S, and 3S+ do use a 5v 3-wire 50x50x15 blower for the parts cooling, but these are different printers, not the MK2.5 or 2.5S

RE: Replacement print fan options

@ryan-f15

Correct, if your printer is a MK2S, MK2.5 or MK2.5S, the parts cooling fan is the 12v, 2-wire 50x50x15mm blower. The Hotend fan on the 2.5 and 2.5S is the 40x40x10mm 5v 3-wire Noctura fan.  

Amazon does sell a 50x50x15 12v 2-wire blower rated at 5500rpm under the "Soundoriginal" brand name.  The wire is too short and the connector will not fit, but you could splice it into the original wire.

So far as the thermal runaway, I know the R4 and R5 extruders tend to thermal runaway when the parts cooling fan comes on. If you examine the blower duct, it blows cold air right onto the heater block by the thermistor.  The R6 extruder has a shroud that better shields the heat block from the part cooling air.  An E3D silicone sock over the heat block reduces this tendency. Parts cooling ducts that shield the heater from the parts cooling air are on thingiverse also.  But if the heater is working properly, no thermal runaway should occur. So, another thing to check is the tightness of the setscrews for the heater connector at the MiniRambo... any poor connection at the MiniRambo power connections or the power supply can cause poor heating which will be made worse when the parts cooling comes on.

RE: Replacement print fan options

@chicago-keri

I don't think that there are any poor connections there.  The only issue I think I have is the fan but I can get a sock I guess.  Is there a recommended one?  The fan I was told to prefer from Amazon was 6500 rpm.  

RE: Replacement print fan options

@ryan-f15

I can recommend the E3D silicone sock. It fits a PRUSA and holds up well.

So far as the fan, try to get as weak of one as possible, the Amazon one I mentioned is fairly weak at 5500rpm and .15A @ 12v. A better choice would be .10A @ 12v, if you can find one. The faster ones are often rated at .35A @ 12v.  In general, you want one advertised as "Quiet" rather than "High Speed", and you are probably going to have to extend the wiring or change the connector. Speaking of the connector, the polarity can vary, so make sure the wire colors match (red to red, black to black)

Good luck!

RE: Replacement print fan options

@chicago-keri

Where do I get one?  Can you post a link?  Why would prusa tell me to get the 6500rpm fan?

RE: Replacement print fan options

You can find a lot of the 12V variant, for example, on Amazon or many other sellers. At higher speeds, the thing just makes more noise and can trigger a thermal runaway with certain filament materials.

https://www.amazon.com/-/de/dp/B08KTJ3H6G/ref=sr_1_4?dchild=1&keywords=5015+fan+12v&qid=1617555782&s=pc&sr=1-4

https://www.amazon.com/-/de/dp/B08R9JW1DF/ref=sr_1_6?dchild=1&keywords=5015+fan+12v&qid=1617555867&s=pc&sr=1-6

https://aruba.desertcart.com/products/172424811-aibecy-5015-brushless-cooling-fan-dc-12-v-0-18-a-turbo-small-fan-ultra-quiet-oil-bearing-6500-rpm-size-50-50-15-mm-for-diy-3-d-printer

....

RE: Replacement print fan options

@ryan-f15

Hi Ryan

Question 1 - Such blowers are available at many places, but the most expedient are eBay and Amazon. Amazon in particular delivers very quickly but a lot of their products are very poor quality. That said, I have been running the one I mentioned above for some time now without issue.

Question 2- Yes, I can post a link but it is extremely likely to change and become extinct after a while. It is far better to search for an appropriate 12v 2-wire 50x50x15mm blower fan on your own and find one that is currently for sale. That said, here is the link to the blower I use. Keep in mind that the wire must be extended. https://www.amazon.com/SoundOriginal-0-10A-0-15A-Humidifier-Aromatherapy-Replacement/dp/B071WMHNG5/

Question 3- I don't know what they were thinking but I would speculate that PRUSA would tell you to replace a 5000rpm blower with a 6500rpm one because either 1- it is easier to find and shouldn't affect operation or 2- they feel that 6500rpm would work better.  My opinion is that whoever made that recommendation hasn't experienced the Thermal Runaway condition when the parts cooling fan starts up on an R4 extruder.

RE: Replacement print fan options

@chicago-keri

Great i have the fan but what about the sock?  Also, this is with petg filament if that helps.

RE: Replacement print fan options

@ryan-f15

Here is a good place to get the socks. They are considered expendable, so they come in 3 packs.

https://www.printedsolid.com/products/e3d-silicone-socks-3-pack

Of course they are available elsewhere such as Amazon or eBay, but Printed Solid is a good vendor. 

RE: Replacement print fan options

Posted by: @chicago-keri

Posted by: @3delight

The fans on the MK2.5(s) and MK3(s)(+) are all 5V fans driven directly from the ATMEGA2560's output pins.  Using 12v or 24v fans can cause problems.

Please check before posting!

The MK 2.5 and 2.5S does use a 5v 3-wire fan for the hotend, but retains the 2-wire 12v fan for the parts cooling fan. The MK3, 3S, and 3S+ do use a 5v 3-wire 50x50x15 blower for the parts cooling, but these are different printers, not the MK2.5 or 2.5S

I do apologise, I got my wires crossed (in more ways than one).  I will edit the post!

RE: Replacement print fan options

@3delight

People make mistakes.  Forums tend to come down hard on folks. 

RE: Replacement print fan options

Posted by: @cwbullet

@3delight

People make mistakes.  Forums tend to come down hard on folks. 

None more so than myself!  Thanks for the support.

RE: Replacement print fan options

@3delight

Feel free to delete my "Please check" post to reduce clutter

RE: Replacement print fan options

@Chicago Keri

It's fine, some useful info there.