New fan/cooling design

[baasb 6]

Hi all,

At this moment I have two fans with fanducts on the printhead which are increasing the weight and size of the head. Due to the mass and size, when printing, the head is vibrating a lot causing a lot of ringing. To reduce this effect, I wan't to replace both fans with simple silicon tubes which are blowing air. This hardly has any weight and is also a lot smaller in size, making the acces to the nozzle a lot better.

I'm still figuring out how to set this up exactly but first I have a question. How many ampere or how many Watts can I draw from the fan-circuit?

 

[nick-foley 5]

I've been thinking about this setup for a while as well - our laser cutter uses a similar arrangement. I'm not positive it's the perfect setup, but it's something I'd like to try.

I'd think the power necessary would be way beyond the fan circuit capacity though. I think an appropriate air source would be a airbrush compressor or maybe a powerful aquarium pump. You could then easily use the fan power on a relay which controlled the AC compressor. Finding a quiet enough compressor for a reasonable price becomes another project then though.

[baasb 6]

For sure, I've been looking for an air-source the past few days. I've got two 12V membrane-pumps laying around but they don't generate enough pressure for a nice breeze. I found some very cheap compressors capable of 30 L/min which is perfect. They're only 10 euro's. I guess they are very noisy ;-)

[baasb 6]

But still, does anybody know how much current I can draw from the fan-circuit?

 

[albert 2]

Have been thinking along these lines too.

A cheap source for a silent compressor is an old refrigerator. I have used that for powering an airbrush for a long time. One can use any pressurable container such as an old gas bottle or even a football as a vessel to get the pulsing out of the air stream. Then use a silicon aquarium type tube to get the air where you want it. The luxury version will include a valve and a water separator to avoid getting droplets of condensed water on the model. I have also used this to cool a frame of film in the projector gate for single frame work.

Some old compressors from the junk pile can be made to run again if one fills in a small amount of oil into the air intake.

[scottvader 0]

Hi Guys

I'm new to the list.

BaasB, such a great idea! I've been looking to upgrade the cooling system as well. I've looked at various ducts and some of my own using Solidworks Flow Simulation, sort of a computerized wind tunnel. Nick, your Tapir Shroud is one of the best.

UPDATED, Sorry I had this wrong, now corrected:

The fan circuit has an NPN (low side) darlington transistor BD679 as a pwm circuit. That transistor is rated for 4 Amps. However, I couldn't get even 1 Amp from it due to noise problems. I was able to put a 1K resistor across the connection and then build my own power control circuit using just the signal.

The reprap wiki in the Ultimaker board says this about the fan output:

 

• [*]

55 Amp MOSFETs outputs (with LED indicators. Actual current capability limited by PCB and connectors)

 

http://reprap.org/wiki/Ultimaker%27s_v1.5.7_PCB

So in theory, 500 watts but with the practical limitation of the board maybe 30 watts, still there's quite a bit more power available there than used by the stock 1.2 watt fan.

What about vacuum instead of pressure? Vacuum draws air from all directions, so would be naturally more uniform in cooling. I'm thinking just hook up a shop vac for testing and later when ideal flow, vacuum and plenum are figured out then choose a blower or pump to go on the Ultimaker.

Incidentally, I've made a 3D printing test part that I'm using for bench marking the cooling system and changes I want to try. Just posted to thingiverse. http://www.thingiverse.com/thing:113440

Scott

 

[jonnybischof 60]

...

I think an appropriate air source would be a airbrush compressor or maybe a powerful aquarium pump...

 

Just to make sure: You know that many aquarium pumps like the popular Eheim or most if not all models used in pc water cooling systems can't be used 'dry'?

They need the liquid to lubricate the bearings, minimze friction and cool the pump...

Edit: how about using an impeller from an rc jet plane? Probably total overkill but maybe there's a small enough model that can be driven at moderate speed. Having a 3D printer, making an interface to the tubes shouldn't be much of a problem...

[nick-foley 5]

I was referring to aquarium air pumps, which certainly don't require liquid or submersion, but regardless, this isn't something I've looked into doing very deeply. My main reason for not pursuing high-velocity targeted cooling is that I don't feel I have a good understanding of what the most desirable cooling result would be, ie: how instantaneously do we want to cool the plastic once it's extruded? ...should it be allowed to slump for a while, or cooled immediately? Is the larger region of cooling provided by a fan more useful in that it cools the whole part, not just the print zone? or if you are cooling the print zone perfectly, does the rest of the part stay cool on its own? Will you need to decrease airflow on the first few layers so that the build platform doesn't redirect too much air back up towards the nozzle, cooling it and reducing extrusion?

I can imagine a pretty sexy air nozzle that surrounded the print head in concentric jets of air, but I don't think I'll be pursuing anything like that because a decent amount of testing would be required to get it right and I've already got my hands full with too many other projects...

Looking forward to seeing other's results though!

 

[baasb 6]

Hi all,

I'm finished with my prototype:

I use a 12V blower. The 220V version makes way too much noise. I'm still experimenting with the air slots that are cut out the silicon tubes. Probably need to redesign the suspension because it's getting soft during print because it's attached to the aluminium plate (although there is some 'insulating' tape in between).

I think with this design, it's really easy to add another splitter with silicon tube which cools the aluminium plate and so creating a cold-zone.

 

[nick-foley 5]

This looks awesome. Could you share some specs on the blower you're using?

You should 3D print the terminating feature of the silicone tube - you could probably create some very useful airflow with the right nozzle shape.

 

[foehnsturm 969]

Hi,

Nice and clean work. Can you give an estimate how much airflow you get compared to the standard cooling fan?

I'm currently testing a radial fan concept with a flex hose. Don't laugh at me it is just a proof of concept ;-)

But it is working very well.

The good news are: the fan generates enough static pressure to get a lot of air through the hose, you can still control the cooling fan speed (difficult with pumps) and the hose doesn't add any moving resistance to the print head.

You have to prevent the hose from swinging, which is easy. The main issue is still the off-centered design of the print head with no space for ducts all around at all (collision with sliding blocks). It is much easier with pumps/compressors and small diameter tubes to get the air to all sides of the nozzle.

Therefore I started to design a new print head for the standard hot end with large integrated air ducts and a centered nozzle position. Due to the centered nozzle you would need to move the end stops quite far, which don't like. So I'm currently trying to adapt Nicks's brilliant Reptar blocks idea.

 

[ulbie 0]

looks realy nice what you both are doing!

i also made my custom fanduct. wanted to reduce mass and the noise of the stockfan. after the assembly i recognize much less vibration on little filling parts and generally during the whole printing session. till now everything works very well, i get good prints and the airflow is pretty good at this point. i'm quiet busy, but i will modify the duct a bit to get even better results. also want to test it with cooled air. i think therfore the prints don't need the much airvolume they need now... perfection ist a must for us maker:)

take a look and don't mind to comment

http://ultimaker.ipbhost.com/uploads/gallery/album_158/gallery_14820_158_805674.jpg

http://ultimaker.ipbhost.com/uploads/gallery/album_158/gallery_14820_158_540500.jpg

http://ultimaker.ipbhost.com/uploads/gallery/album_158/gallery_14820_158_78005.jpg

http://ultimaker.ipbhost.com/uploads/gallery/album_158/gallery_14820_158_488504.jpg

next step for me is a complete new printhead with integrated cooling. in about a month i think i'm finished and will show to you.

greetz, ulbie

ps: sorry for my english, i'm no native and not so into languages;)

 

[nick-foley 5]

Another great execution. Those 3D printed outlets are exactly like what I had in mind.

 

[scottvader 0]

Such great work!

I was going down the blower road suggested by BaasB but then realized we actually want high air flow with low mass. The frequent answer to that problem is a propeller.

Here's my recent cooling system upgrade. The standard Ultimaker fan and duct weighs about 25 grams and pushes about 3 grams per second of air. This mod uses two Blade Nano RC helicopter tail rotors. They weigh under 3 grams each and they push about 9 grams of air per second each. So an order of magnitude more air. With the mass saved, I added a camera and still kept everything under 25 grams.

Initial testing indicates it allows the Ultimaker to run about twice as fast on PLA.

It's up on thingiverse at http://www.thingiverse.com/thing:125244

The camera is pretty fun. I was at Detroit Maker Faire this weekend with the UItimaker with this set-up. People were walking by the other 3D printers and then saying "look, they've taken a video and then sped it up so you can see it building ... No sir that's real time video of an Ultimaker.

Scott

 

[baasb 6]

Very nice design foehnsturm! The first thing were I was looking for when starting with a new cooling design was also a radial fan. But I could only find very expensive ones which could not blow air trough the small silicon tube that I use.

But seeing your design makes me realize that it just takes a bigger tube to ensure a good airflow! What's the name of the tube you're using?

 

[foehnsturm 969]

It is called "Suction-pressure coil hose PUR light 30mm Standard"; see: https://www.landefeld.de/artikel/en/suction-pressure-coil-hose-pur-light-30mm-standard/PUSPL+30.

It is definitely a matter of free cross sectional area. But the drawback is that you need to maintain this cross section besides the print head, which is almost impossible with the standard one. I tried ulbie's idea of running the air through the standard head (modified top plate) and the two big holes in the base / aluminum plate as well. But with my fan this proved to be a bottleneck. This is the sole reason for those weird, self-made latex tubes, which can be squeezed easily during print head homing.

 

[ulbie 0]

True, true...for this kind of cooling the cross section is all that matters to get a good airflow, or the temperature with less airflow (will be tested soon) I like the centric thing foehnsturm made, but in my case I wanted to use the holes in the top and bottomplate. I had to drill another hole on the left side to get the 2 tubes through.

The assembly was pretty easy and was no problem. I'm also using a radial fan. If you have the chance then look inside of old workstations or other pc's...there I got 3 of em out:)

Foehnsturm, I guess with your solution you are loosing a bit of printarea, right?

[ulbie 0]

Btw, here is another source for flex tubes

http://www.flexschlauch-luebeck.de/produkte/produktkatalog/polyurethan.php

[foehnsturm 969]

Foehnsturm, I guess with your solution you are loosing a bit of printarea, right?

 

Actually not because I'm squeezing those tubes between the head and the frame (but of course the cooling won't work completely when using the outmost 5-10 mm of the printing area.)

 

[foehnsturm 969]

It took me 7 iterations to find a way to arrange 2 linear bearings, bowden tube and accessories within a 45x45 mm box while maintaining the airflow and dividing it almost equally at the bottom. But I'm not a specialist in that.

As the print head is not longer centered to the x/y rods, I have to redesign the sliding blocks or move the end stops to maintain the printing area.

 

[ulbie 0]

Nice! Like to see the endsolution. Very interesting because I have some same ideas for my printhead. At this moment I'm just sketching and brainstorming, but soon there will be a new design. Hope you have much success with your stuff!

[tz-advantage 0]

I was thinking about a new head design for the ultimaker along the same lines that has internal holes to direct an airflow provided by a fan or hose on the top. The top is now just a 'clamp', holes for mounting a fan or hose has still to be done.

It is also for mounting a second extruder. The Bowden tube(s) will be clamped.

I have stopped with it because of lack of time but for someone who is interested i have a sketchup model available that can be printed in 4 parts and is a replacement of the current head.

Here is a picture of it.

 

[ulbie 0]

hey guys...just wanted to show you the latest status of my fanless printhead. it is almost finished but soon there will be a new printhead design 100% working.

take a look if you want and let me know if you stick out some issues or have suggestions for improvement

http://ultimaker.ipbhost.com/uploads/gallery/album_174/gallery_14820_174_525550.jpg

by the way, how can i put the pictures directly in the forum without a link like the pictures above??? don't have time to search for it:)

up soon,

ulbie

 

[lars86 42]

@baasb @tz-advantage @ulbie @foehnsturm

Did you guys continue developing your ideas? I have been scheming about a similar cooling setup.