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Printing in a vacuum?

Posted by muntahunta 
Printing in a vacuum?
September 15, 2015 01:17PM
Basically Im wondering what the best idea would be...

I've seen some print enclosures out there with only an exhaust fan but no intake, while being completely sealed (or as close as possible)

Now, While I think this would reduce some sound issues, would the printer electronics overheat? or would it cause any problems?

Or would it be better to include an intake fan too...
Re: Printing in a vacuum?
September 15, 2015 02:14PM
Sorry if my question seems daft but...

The upside of of the trouble to getting to vacuum would be?
Re: Printing in a vacuum?
September 15, 2015 03:23PM
I don't think the minimal pressure difference that could be obtained by a fan would have any effect on noise- most of the noise from the printer comes from motor vibrations coupled to the printer's frame. Even a complete vacuum wouldn't prevent that.

The electronics would have to be kept outside the vacuum chamber- common electronic components aren't designed or rated for operation in a vacuum. Motors would be OK, but then lubricants become a problem as they will boil in a vacuum and deposit themselves on everything in the vacuum chamber including the plastic being printed.

A vacuum won't transfer heat except by radiation, so printing ABS would be a problem because it would be hard to keep the print warm as it is printing. OTOH, the plastic may not cool after coming out of the extruder so maybe you'd end up with a gooey mess or maybe even ABS would print OK.

It would be an interesting experiment.


Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]
Re: Printing in a vacuum?
September 16, 2015 04:34AM
Hi,

Sound (noise) are vibrations spread thru the air.
Vibrations can spread thru solids too, and solids can act as amplifiers.
Athmospheric pressure will just act on sound spread speed,
but not in measurable ways for our ears.
OTOH, I don't believe you could build a proper pressure enclosure
to get a significant PSI difference to change drasticaly environment's properties.
If your goal is to reduce noise, two principles may help.

First the solids. You can insulate vibrating elements (motors),
to provide solid transmission.
Usualy makers uses soft materials, like rubbery materials.
It may help on some frequencies (a part of the noise),
but induce some flex into the mecanical assembly too.
So cushion must be prioritaly set between non mecanical elements.
The "box in a box" system or suspended tray in a box works great.
It's better to use hard rubber or any anti-vibrations hard material,
like an concrete epoxy plate, for example.
Another way, is to use heavy materials as structure because vibrations
looses amplitude while crossing large masses.

Seccond, soundtraps.
Once vibrations cannot propagate anymore,
you want to anuhilate them.
There's no better way than to cover all the inside walls of the outer box,
with absorbent material, like glasswhool.
That will prevent air vibrations to reach the box walls,
then cross the material, then spread thru the air outside.
The tray supporting the machine can lay on a real sandbox.
The sand will provide a strong support, and all the grains
will prevent any vibration transmission.

To find where vibrations spread on amplify in solids,
just touch softly the material with your fingertips,
you will be able to feel the vibrations.
Sometimes you may find the table or the frame
vibrates more than the motor itself.

Last, the best way to fight noises,
is to don't have noise generation.
Silent drivers operate steppers silently,
and bronze or polymer bushings slides noiseless.

++JM
Re: Printing in a vacuum?
September 20, 2015 01:01PM
Extruding plastic in a vacuum would likely lead to undesirable results, for example you are more likely to get tiny bubbles in your prints. The sound dampening would be minimal because very little sounds is actually produced by the extrusion process itself; the noise comes from the stepper motors.

But pulling a vacuum on your printer would be very difficult and not going to happen by accident, and certainly not with a couple of small fans.

The primary disadvantage of not allowing for an air intake is that your fans will be less efficient. You don't need a fan blowing inwards, you just need holes in the case for air to flow in, and most printers have plenty of those.
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