Magnetic holder for extruder fans

Markus64
Posts: 242
Joined: Thu Feb 27, 2020 4:57 pm
Location: Germany

Re: Magnetic holder for extruder fans

Postby Markus64 » Fri Oct 09, 2020 10:17 pm

@Kurtyard,
I can only repeat myself: A fantastic addition to the Pro2! :D :D :D
Thank you for sharing your data with us! I hope Raise recreates that :mrgreen:

Kurtyard
Posts: 41
Joined: Tue Jul 04, 2017 9:55 pm

Re: Magnetic holder for extruder fans

Postby Kurtyard » Sat Oct 10, 2020 2:29 pm

The fan housing was slightly deformed after 14h print (Amazon ABS) so ABS is not the best choice for this part. For the holder parts ABS is fine. I will create a adaption to the original housing, then. Alternative to print with 3dktop filament etc. which withstands heat up to 230 Degree.

Markus64
Posts: 242
Joined: Thu Feb 27, 2020 4:57 pm
Location: Germany

Re: Magnetic holder for extruder fans

Postby Markus64 » Sat Oct 10, 2020 2:40 pm

@Kurtyard,
I am currently printing the first parts with ApolloX from Formfutura. According to the data sheet, the filament is heat-resistant up to 230 ° C. The filament can be printed like a dream. I will report whether the stuff is any good.

The following consideration: could it be that the aluminum protective shield has the opposite effect? Based on your experience, I will test this area with Kapton tape.

Kurtyard
Posts: 41
Joined: Tue Jul 04, 2017 9:55 pm

Re: Magnetic holder for extruder fans

Postby Kurtyard » Sat Oct 10, 2020 3:19 pm

Ok, i'm curious about the result...3dk top has to be post proccessed in oven, to make it heat resistant. Another idea could be a aluminium heat shield which is wrapped around the 'closer to nozzle' edge

Markus64
Posts: 242
Joined: Thu Feb 27, 2020 4:57 pm
Location: Germany

Re: Magnetic holder for extruder fans

Postby Markus64 » Sat Oct 10, 2020 3:27 pm

Or a silicone sock, similar to the hotends. The stuff can withstand more than 400 ° C. A mold would be easy to construct. The sock only has to cover the front area and could "snap into" a gap.

Kurtyard
Posts: 41
Joined: Tue Jul 04, 2017 9:55 pm

Re: Magnetic holder for extruder fans

Postby Kurtyard » Sun Oct 11, 2020 7:31 pm

I ordered a 320gr roll of 3dk top filament, it crystallizes in oven, takes 1 hour and slow cooling to make it heat resistant and more robust (mechanical) . According to the manufacturer it was designed for engine near parts. Looking forward to a test. For the time being :
Attachments
20201011_185135.jpg

JPT
Posts: 5
Joined: Tue Sep 08, 2020 11:13 am

Re: Magnetic holder for extruder fans

Postby JPT » Sun Oct 11, 2020 8:25 pm

Kurtyard wrote:to make the access to the hotends as easy as possible i chose a design which transfers the current through the magnets, so i can take the fans off completely.


This is a fantastic idea.

I love the idea of using the magnets in the circuit.



RE: attaching the wires to the magnets

Image

Note that heat will kill the magnetism in the magnet, so it's easy to ruin the magnet while soldering.

As an alternative, there are small disc magnets available that are countersunk, so you can use countersunk screws to complete the circuit.

Here's an example of a countersunk magnet:
https://www.magnet4sale.com/n45-disc-neodymium-magnets-w-4-countersink-3-8-x-1-8-rare-earth-disc-magnets/

Here's how one looks assembled:

Image

Note that you may not need a magnet as thick as this one in the example photo for this application.


These are the parts required:

Image

The hardware in this shot is from McMaster Carr

For the connectors, brass is actually a poor conductor and steel and stainless steel are the worst among commonly available hardware.

Zinc plated steel is the best of commonly available hardware.

This screws in the photo are aluminum screws from McMaster Carr. Those aluminum screws are extremely expensive, but they are the best conductor available, at least that I could find.

For this fan application, zinc is probably fine.

Note: I have no affiliation with the magnet vendor, McMaster Carr, Ancor, or any other vendor in this post.

Kurtyard
Posts: 41
Joined: Tue Jul 04, 2017 9:55 pm

Re: Magnetic holder for extruder fans

Postby Kurtyard » Tue Oct 13, 2020 4:13 pm

@JPT good point (s)...i thought about the heat and a solution for clamping the magnets instead of soldering, but after some testing i decided to solder these magnets, for 4 reasons:

the construction should be slim
it should be lightweight
it should have a huge contact area
no electrical loss due to additional materials and connections (as you mentionend)

which all is given with 10x1.5mm magnets.

if you take few points into consideration, the magnets keep their strenght.

Put the magnets on a steel plate to keep the magnetic force while soldering.
The steelplate will cool the flat magnet, only the surface spot which is going to be soldered is heated up
Grind the small spot to get a fast connection with the solder
Do not use a solder iron for roof gutter..
Use a N52 magnet
Tape the magnet down, despite the magnetic force - to prevent accidently sticking to the solder iron

The magnets should be at same strenght as before - and N52 strenght is actually more than needed, so any loss doesn't matter.
They will keep their strenght in future as they are allocated face to face

Markus64
Posts: 242
Joined: Thu Feb 27, 2020 4:57 pm
Location: Germany

Re: Magnetic holder for extruder fans

Postby Markus64 » Thu Oct 15, 2020 4:26 pm

I have adapted the fan solution to my needs. I wanted to reuse the original fan housing, as they are resistant to high temperatures.
Cable ducts are integrated into the fan holder, which is why I can do without panels. The solution shown here is ideal for me.
Thanks again to Kurtyard for this inspiration! :D

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Kurtyard
Posts: 41
Joined: Tue Jul 04, 2017 9:55 pm

Re: Magnetic holder for extruder fans

Postby Kurtyard » Thu Oct 15, 2020 9:35 pm

Perfect, this will definetely work!! It‘s some efford to set this up, but once done it makes life easier. I would love to have a system which doesn‘t require all this, neither magnet holder nor liquid cooling. :roll:
Your system with all the big and small improvements rocks, would like to see a long term competition with a standard system. Raise probably not. :D
I‘m still waiting for my order of the heat resistent filament, which changes the melting point after print.

Markus64
Posts: 242
Joined: Thu Feb 27, 2020 4:57 pm
Location: Germany

Re: Magnetic holder for extruder fans

Postby Markus64 » Thu Oct 15, 2020 11:13 pm

The effort is definitely worth it! You should actually expect such innovations from a printer in this price range! It's just a shame that we can't lend a hand to the Firmware. 8-)


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