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tommyph1208

The air pump approach

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Hi all...

So in the eternal quest of lowering print head weight, I had an idea... AFAIK nobody has tried it before, and perhaps there is a reason for this, so I wanted to run it by the forums before doing anything else...

As with the crossflow fan approach, my idea revolves around removing the bulky and heavy fan and fan mount from the printhead... Instead I wanted to add a small electrical air pump somewhere on the printer, and run a flexible silicone tube with air flow, along side the bowden tube, with its end pointing directly (or slightly below) the nozzle tip...

The way I see it, the tube would be very light weight and take up next to no extra space... definitely an improvement over the fans and fan mounts.

The air flow would also be very centered on the newly extruded plastic, and not all over the place like the nozzle, heater block etc.

So... What am I missing? would it be impossible to get enough flow through the tube without a big ass (and very noisy) pump and equally big tube?

How much flow is actually needed (when taking into account how precisely it can be directed)?

I quickly found this 12v dc pump on ebay: http://www.ebay.co.uk/itm/12V-Small-Air-Pump-Mini-Electric-Air-Pump-Compressor-/281488704341?pt=UK_Pet_Supplies_Fish&hash=item418a08c355

Probably too weak right?

Thoughts and comments are very very welcome

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Fans need to be carefully matched to the pressure. You cant take the existing UM fan and expect it to blow air down a tiny tube - it's not that you need to shrink it down with a funnel. It's the blade shape in the fan itself that won't work with high pressure.

Some fans are designed for high volume, low pressure. You need low volume high pressure. You don't need a fan that sucks down any more watts it just needs to be designed to blow through tubes. One of those centripital fans. Like you see for a bouncy castle or vacuum cleaner. Not like the kind in a window.

So yes it's a great idea, just make sure you get the right kind of fan - designed for sending air down tubes.

 

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Fans need to be carefully matched to the pressure. You cant take the existing UM fan and expect it to blow air down a tiny tube - it's not that you need to shrink it down with a funnel. It's the blade shape in the fan itself that won't work with high pressure.

 

Some fans are designed for high volume, low pressure. You need low volume high pressure. You don't need a fan that sucks down any more watts it just needs to be designed to blow through tubes. One of those centripital fans. Like you see for a bouncy castle or vacuum cleaner. Not like the kind in a window.

 

So yes it's a great idea, just make sure you get the right kind of fan - designed for sending air down tubes.

 

What about an actual pump?

Like the ones for sending air into the water in aquariums?

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i would see a different issue;

not just the airflow but also the spread of air.

if you deliver this with a fan, you get 90 mm of airspread with a 90mm fan (approx). with a tube of 10mm, you will get very directed air.. but you want to cool a larger area.. this means you now have to put something on the front of your tube like a garden hose to "spread" the air again, making it noisy..

 

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i would see a different issue;

not just the airflow but also the spread of air.

if you deliver this with a fan, you get 90 mm of airspread with a 90mm fan (approx). with a tube of 10mm, you will get very directed air.. but you want to cool a larger area.. this means you now have to put something on the front of your tube like a garden hose to "spread" the air again, making it noisy..

 

I'm not sure I agree with this...

Alot of 3d printer fanducts are designed to funnel the air and direct it right below the nozzle tip... Like:

http://www.thingiverse.com/thing:17768

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Just make sure you buy a "blower" and not a "fan". A fan has about 5 blades. A blower has about 50 blades. That's all you really need to know.

 

Thanks for the info, I didn't know that, just like Tommyph1208 exploring what kind of cooling fit's the best for my purpose.....

 

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i would see a different issue;

not just the airflow but also the spread of air.

if you deliver this with a fan, you get 90 mm of airspread with a 90mm fan (approx). with a tube of 10mm, you will get very directed air.. but you want to cool a larger area.. this means you now have to put something on the front of your tube like a garden hose to "spread" the air again, making it noisy..

 

It could be, but if you print a big part you don't really need the cooling there, just close around the nozzle will do.

For more then 70% of my prints I don't use the fan at all, only for tiny prints the fan is switched on.

From my experience, a wide spread air flow attached on the printhead will not only cool the filament but also the heated bed and in worse case the nozzle itself.

 

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I already did at the beginning when foehnsturm posted that thread.

I've tried it but for me the only downside of that cooling system is that the cooling from the blowing side is good, the other a little less.

I also attached a kind of flow directioner onto the print-head but didn't get the results I wanted.

As I already mentioned, I only use cooling for small parts.

It's not that I'm actively seeking for an alternative cooling for my printer, only commented that I've tried aquarium air pumps :-)

 

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Alot of 3d printer fanducts are designed to funnel the air and direct it right below the nozzle tip... Like:

http://www.thingiverse.com/thing:17768

 

I think those fan ducts do more harm than good. The fan ends up sending out almost no air at all. I tried a few of those and went back to the original design. Some of them are okay but if you constrict the flow too much you end up with almost no flow at all. The fan just isn't designed for ducts. Try measuring the flow with and without the duct. I did and was a little surprised.

 

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Since the point of blowing air onto the print is to spot cool what has just been extruded, then isn't another factor the temperature of the air that is being delivered? If so, then compressed air that is at room temperature while under pressure will deliver a lot of chill for little flow. Perhaps an airbrush pump paired with a tank connected to something like Chopmeister's rig would do it.

Edit: this looked interesting. I have no idea the cost.

https://www.vortec.com/Asset/Cold_Air_Gun.pdf

 

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Hey guys,

FYI, I bought a cheap aquarium blower for 25$ attached 2 silicone tubes , made flattened endings from aluminium tape and mounted them about 1 cm away from the nozzle, on both sides. Works like a charm.

I also got 2 small centrifugal fans which i'll be testing now. After artificially narrowing the exhaust, the air output is comparable to aquarium pump, but a bit stronger and more even - the aquarium pump literally sends air in mini blasts.

 

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Hey guys,

FYI, I bought a cheap aquarium blower for 25$ attached 2 silicone tubes , made flattened endings from aluminium tape and mounted them about 1 cm away from the nozzle, on both sides. Works like a charm.

I also got 2 small centrifugal fans which i'll be testing now. After artificially narrowing the exhaust, the air output is comparable to aquarium pump, but a bit stronger and more even - the aquarium pump literally sends air in mini blasts.

 

Very interesting! - could you pleas epost a few pictures - would help to imagine you rsolution :-)

Thanky in advance

 

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