To fan or not to fan or more accurately Where to fan.

Not so much about not having a fan but I have been watching loads of print/tutorial videos and have noticed some Printers have fans that blow onto the prints to help cool material.

I was thinking if a fan or 2 is used to cool material blowing from each side on trickier prints could you have 4 fans mounted around the Extruder and have them turn on depending on where you have printed.

So for example you print a bust at 0.2mm layer height and need it cooled while the extruder is running the fans would trigger as follows.

Right on the X axis front fan blowing
Up the Y axis the right fan is blowing
Left on X Axis the back fan is blowing
Down on the Y Axis left fan is blowing.

Might be a bit over complicated just thinking of being able to direct air where you need it rather than blowing it over the whole print.

I don't think that switching fans on and off is a good idea... it's going to take a few seconds for a fan to ramp up to speed, and you don't want to be stopping for a few seconds each time you change direction by 90 degrees or more.

Much more important is to have a blower (radial) fan, rather than the common axial ones, and to have the fan ducted to blow a fairly wide stream of air just below the nozzle. The direction it blows is secondary.

Extra mass on the print head is also a bad idea (even though fans are light)... it reduces the speed at which you can change direction, and therefore overall print speed.

Thanks for the info I was just thinking of having a more precise jet of air directed to the nozzle.

Maybe a 2 into 1 duct that blows directly down between a dual extruder setup would be better.

You want to keep the cooling air away from the nozzle and direct it only at the printed part. You want to start cooling the plastic, after it has adhered to the previous layer and only to prevent the printed part from "sagging". TBH, these days and in spite of what is perceived to be best practice, I'm not using any print cooling (but I only print PLA).

Edited 1 time(s). Last edit at 10/19/2016 11:35AM by deckingman.

I'm just getting my brain working to try and figure out ways of doing things that would make my printer more streamline.

something that covers the Nozzle/Nozzles but lets the air pass to the print in a more uniform way rather than just blasting the whole print with cold air.

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Out of the box thinking is easier when you never fitted in the box to begin with.

Quote
Rlewisrlou666
Thanks for the info I was just thinking of having a more precise jet of air directed to the nozzle.

Maybe a 2 into 1 duct that blows directly down between a dual extruder setup would be better.

Some people are using aquarium air pumps to blow air through a nozzle adjacent to the extruder nozzle. You mount the pump on the printer's frame and run the air through a hose to the extruder carriage, so added mass is minimal. Air pumps, unlike axial fans, are able to deliver air flow through a hose and a restricted nozzle. I have such a pump (4 l/m rating) and intend to mount it on my printer for testing, soon.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

That's a good idea DD!

@the_digital_Dentist - Kinda like the same way that an air/mist feed would clear chips from a CNC/Lathe/Mill I had thought about that option I didn't think of using a Fish Tank Pump though. Thanks for the advice.

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Out of the box thinking is easier when you never fitted in the box to begin with.

I use a positive displacement pump, either an aquarium pump or a miniature Rootes blower feeding through 6mm bore silicone rubber tubing to an air ring around the nozzle. This works but I can't honestly say that it is a magic bullet for cooling. Slightly more useful is that having a fan directed at a big sharp edged block gives a very turbulent air flow which cools down into gaps where other shrouds can't reach. Both of these are shown in the cross sectioned diagram below.


Mike

@leadinglights - Nice rig. Did you fabricate/Print the air ring yourself?

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Out of the box thinking is easier when you never fitted in the box to begin with.

The air ring is made from thin brass sheet bent around wooden blocks and soft soldered. Insulation used to be cuttlefish bone but I now use kiln paper. Diagram below shows the general construction.



Mike

Would these be of any use to anyone for Air Pump blowers.

[www.ebay.co.uk]

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Out of the box thinking is easier when you never fitted in the box to begin with.