Better Cooling For Deltas

I have been trying to figure out a way to create a better method of cooling at the hot end of the Delta's that my friends and I are working on. Right now my concept is to run a tube down to the nozzle to cool layers instead of having a fan near the head. The theory is that the tube is lighter and will not get in the way of prints and will not hit the sides of the machine.

Materials
The plan is to use flexible tubing with 1/4" ID and 3/8 OD that is readily available from the local hardware store.

What I Have Tried
I have tried the Bowden Cooling Tube suggested in the link. It works decently, however, it pushes a very large volume of air (for its size) but it does not create much back pressure which is what is needed. This is due in part because you are taking a 30mm opening and shrinking it down to 9mm. Even if I tried using baffles I doubt it would work much better than it currently does.

I have also tried using multiple fans placed in series. I tested this with some larger fans that were pulled from computer cases and the concept does work. I have not yet tried it with the smaller 50mm fans that I am wanting to use. The idea here is, the first fan blows into the second fan which lowers the amount of force needed to drive the second fan allowing it to spin faster and push more air. There was a noticeable increase in the air flow when I tested it with the larger fans but its hard to say if that will translate well when scaled down. Distance between the fans does make a difference and I will be setting the tests up in such a way that I can make adjustments to try to find a sweet spot.

I also have a Keedox Brushless Water Pump coming in from Amazon that I will be trying out as well. This may put out enough air my only concern is vibration and noise. Neither should be much of an issue but until I have a chance to test the pump and to see what kind of output, vibration and noise it creates then I will keep it suspect.

What I Am Looking At Trying
I am going to be printing up a few different styles of turbines to try as drop in replacements on some older fans that I currently have. If they work well I will design up a housing to channel the airflow into the tube and see if I get the amount of airflow that I am looking for.

If anyone has any input on this topic or has tried similar things, please let me know! I think that this could be a great thing for all Delta's out there but I just need some more feedback.

Fans cannot build up much pressure, since the backpressure just slips by the ends of the blades. (I went through a few aggressively-pitched propellers in my boat fighting the cavitation.) Tighter housing tolerances will get you more pressure, but the only way that you will get significant pressure is to use a compressor, such as a piston, turbo wheel, or turbine.

Also, let me throw in a word of caution that the pump you are looking at might use the water passing through it as a coolant, and I suspect that it will overheat before long with only air passing through. A byproduct of compressing air is heat, which is why turbocharged cars need intercoolers to cool the compressed air before pushing it into the engine.....

I am aware of the possible over heating issues but considering the price it was worth experimenting with.

Thank you for the advice!

The water pump won't work, air is so much less dense it can't be pumped by a water pump impellor. What you need is an Ametek Microjammer or similar. These are brushless motors because they need to revolve very fast. They alos have mutiple stages to get the pressure up. Using a larger tubing would help a lot.

I revieved the water pump just a few minutes ago and tested it with a power supply, it was a fool hearty experiment. It is to noisy to put with a printer and causes vibration.

With the Ametek Microjammer it is to big to hide somewhere inside of a delta bot's frame. We are hoping to use something small in several printers that will be quiet and take up repetitively little room. Its alot to ask for but that is the goal.

On using the large tubing, it will allow for more air flow but it doesn't have as good of a bend radius as the smaller tubing due to the thicker walls it uses to maintain its shape. That can cause the Delta effector to misbehave when you begin to limit the movement.

I am looking into changing the way in which the nozzle rides within the effector in order to put small fans in that can cool the extruder and also channel air to help cool prints. I will post any updates I have with success and failures.

Thank you all for the info so far! Please keep it coming!

Rather than a fan, how about just a pump (like in a compressor), into a accumulator tank that then feeds your blower hose?

Something like a reciprocating piston pump driven by a crank, combines with a couple of valves (marble+spring, diaphragm flap, etc.)

-Rob A.

Some have tried the air pump for the aquarium, and everyone was happy. If interested, I will provide a link to the forum, but in Russian.

Quote
pamalofeev
Some have tried the air pump for the aquarium, and everyone was happy. If interested, I will provide a link to the forum, but in Russian.

I'd like to see this.

Starting from this post.