New cooling solution prototype

  • I wasn't happy with the performance of the side mounted fan duct. Especially on small parts the air did not come close enough to the nozzle and because of the sideways acting force provided by the airflow the parts could deform during printing. Additionally the cooling effect was different on all sides of the model.

    There are some alternative designs like which looks very promising but i decided to design my own.

    Design goals:

    • airflow as close as possible at the nozzle
    • equal cooling on all sides
    • simple mounting, if possible single part design
    • include 40mm hotend fan adapter for silent operation

    After a lot of tinkering and testing i came up with a very unique (?) solution.
    It's a single part print without support which attaches magnetically to the screws/nuts on the extra mounting holes on the smart effecor. So these can still be used for mounting i.e. a zesty nimble (like on my printer) and the assembly can be taken off within seconds.
    For part cooling i'm using a blower fan because high pressure is needed which axial fans do lack, i used a 50mm one but 40mm might work, too (couldn't find one locally which was specified at 24V)

    0_1543349375840_FanDuct1.GIF 0_1543349685942_IMG_20181127_203615.jpg
    2_1543349685942_IMG_20181127_203709.jpg 1_1543349685942_IMG_20181127_203655.jpg
    (sorry for the bad image quality, it was too dark and the images hat to be reduced in quality quite a lot before uploading)

    Thickness below the heatblock is 2.2mm, so there is still more than 1mm of clearance to the printed part, weight is 19g.
    The prototype was printed in PLA which obviously isn't a great choice when mounted that close to the heat block 😉 It's ok when the part cooling fan is on but will deform quickly if its off.
    I will probably use nylon when i'm happy with the design.

    I'm just 1 hour into the first print so i can't say much about the viability of the design yet.
    The design is not yet published, but will be soon and will be open source.
    The smart effector model which i used to design the cooling solution is already available on thingiverse:

    I would be happy if you could provide some feedback 🙂

  • Some more clearance around the hot block sock would be good for the vertical mount pieces -- they're under load and not directly cooled by internal airflow so they're going to be most susceptible to excessive temps.

    For example, the one support on the open side that looks like it's touching the sock -- you could support the screw mount off the hot end fan duct with an overhang rather than taking it all the way to the bottom plate past the sock.

  • Why not use something like the berd air? All you have is a small piece of aluminium tube and some silicone hose. Takes up less room and also reduces weight.


  • @RCarlyle
    Only one vertical 'post' is directly touching the the sock and that's only because the heat block is rotated the way it is. The two other posts have about 8-10mm clearance to the sock, just rotating the heatblock 45 degrees would give more than enough clearance on all vertical posts.
    However i think contact to the silicon sock is not a problem as the plastic is a very poor at transfering heat, so only a part of the post is getting warm (and the silicon itself limits the amount of heat transfered, too). My hotend cooling fan printed from PLA dropped directly touching the heatblock and only melted at the contact surface.

    I already considered the berd air and i may use it if my design fails.
    However the berd air has a lot of downsides:

    • noisy
    • additional electronics needed
    • additional mounting parts needed
    • not easy to assemble
    • still requires separate hotend cooling fan
    • no international shipping from the United States to Europe and not available locally

    In fact the berd air was one of the inspirations for my design as i wanted to design something that provides similar performance but without some of the downsides. Of course my design has other downsides like the amount of space needed and additional weight at the effector...

  • @Nuvag

    The berd air is actually quite quiet. I only have to run mine at maximum 30% speed. The assembly is actually really easy and I have not had to add any extra electronics as I have remapped a heater output for the air pump. I like it as there is very little hanging around the heat sink. Yes you still need the hot end fan but you have dropped the weight of a heavy blower or two as well as printed parts. I drew up a clamp for the pipe that is two pieces and I was sorted. As for shipping, I just brought a pump of aliexpress and went and got some aluminium tube from a hobby shop and the silicone tube from a pet store for the pipe (was the cheapest place to get it)

    Those are my thoughts anyway.

    Regards Sam

  • @Nuvag I like it! Have you thingiversed it yet?

  • @samlogan87
    Which inner/outer diameter silicone tube did you use?

    No i'm still iterating on the design, but i uploaded the stl here so you can have a look:
    0_1543426343933_Fan Duct.stl

    I designed it for printing with my 0.25mm nozzle, so wall thickness is usually 0.6mm. Should be printable with a 0.4mm nozzle as single walls however. Layer height: 0.15mm
    I added a sacrificial bridge where the nozzle will go.
    Magnets used are: dia 5mm, length 8mm but you can use smaller ones and glue them in.
    Blower: dia 50mm, width 15mm, hotend fan: 40x10mm
    Weight is down to 12.9 grams in the current iteration.

  • @nuvag said in New cooling solution prototype:

    No i'm still iterating on the design, but i uploaded the stl here so you can have a look:
    0_1543426343933_Fan Duct.stl

    Thanks, man, I will take a look.

  • "Berd-Air": "555 pump" on AliExpress 12/24V, silicone hose from aquarium pumps, 4mm OD/3mm ID pipe (I have brass b/c that is what I've found) ~ $20 in total. Beats the hell out of any fan in terms of actual moved air. Fans are nice if there is zero backpressure.
    Bonus: near instant start-up. Show me a fan that has this.

  • The design is now up at thingiverse:

    Sorry for the delay, i had to setup a new pc and was on vacation for a few weeks.
    I incorporated some small improvements but noting major changed.

    It's still a work in progress and im not happy about some design choices:

    • the 'fingers' that point to the nozzle can deform easily and get destroyed
    • the air blows at the nozzle and is reflected down, this cools the nozzle and heats up the air
    • i can no longer see the nozzle while printing, maybe a 270 degrees cooling would be good enough?
    • the 50mm blower is probably oversized, i may try a 40mm blower

    I did print one using Taulman Alloy 910 (Nylon), but havn't tested it yet.

  • The description of states that there is no improvement going from the 180 degree version to 270 or 360 degree versions when printing Benchy, but the author also states they went with the 270 version. So, a 270 version would be nice (-:

  • I suspect if the air can be directed very close to the nozzle tip it isn't necessary to provide a 360 degree cooling.

    My current plans for the next iteration:

    • 270 degrees cooling, so the nozzle tip can be seen again during printing
    • remove the 'fingers' and prohibit the air from blowing directly at the nozzle so the air stays cooler
    • use a 40mm blower instead of 50mm to reduce footprint and weight
    • maybe use a 40mm blower for the e3d heatsink as well? The fan duct uses a lot of space currently

    Any idea where i can get a high quality 40mm 24V blower fan?
    The 50mm one i'm currently using has pretty bad vibrations 😞

    Maybe the old style silicon sock would be better suited as it shielded the nozzle better.
    I suspect the radiated heat from the nozzle is a problem both for the print and the fan duct.

    Where the screw that tightens the heater cartridge radiates heat, the fan duct fails first. It burns a hole in the PLA the size of the screw head.

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