Any submillimeter powder dispensers out there?

I want to dispense powders through a nozzle, like 0.5mm, to turn the standard powder printing process on its head. Instead of adding a full sheet of powder and then curing selected areas with a laser, I want to lay down powder ONLY where I want it using a nozzle. I've read about many many designs of "powder dispensers" or "powder nozzles" but I have not been able to find anything close to this. Most powder dispensers really refer to powder-liquid slurries.

There are a bunch of Reprap pages mentioning a powder dispenser, but they never discuss the nozzle or mechanisms. Often ultrasonic is briefly mentioned, but no sources. However, there are reports in academic literature for designs down to .12 mm that "micro feed" powders somehow. Has anyone thought of this or seen anything that works?

Thanks in advance.

... powder cloggs thin tubes, so mostly used as slurry with evaporating solvent (e.g. pure Aqua dest.or mixed with Dexpanthenol for some viscosity).

Best use microspheres instad of milled powder ...

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Viktor
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Hey Viktor!

Thanks. My motivation to use powders includes food decorating, so I wanted to come up with a way to use ordinary powders (even with a few % trapped moisture) and what I thought was relatively large (0.5-1 mm) diameter nozzle. I understand why they do it the way they do now, but I want a non-solvent based method if possible. If no one has heard of any, I'll try to build one...if it works, do you think it has any value beyond food and drink decorating? It could potentially be used to lay down materials like powdercoating - it is typically a polyester or polyurethane - and then sinter them with a flash lamp or strong infrared energy source - in what could be a batch version of an SLS process?

Thanks,
MIke

I could see it potentially working by trailing the powder deposition head with a high intensity heat source to sinter the material as its deposited, but I think the nature of powder is going to preclude the ability to do any really complex geometry like thin walls or overhangs.

The commercial equivelant of what you've proposed is a process known (in the additive manufacturing world) as DMD (Direct Metal Deposition); Whereby a metal powder is jetted from a nozzle and instantly solidified using a high powered laser. The technologies most common use is in the repair of expensive metal components (think jet turbine blade etc.) due to its unique ability to deposit material onto another object in any given XYZ. However it can also be used as an additive freeform fabrication process to create near net shapes from scratch.

In a way the process is quite analogous to FDM - a deposition head containing both material feedstock and heat source moved around on an XY gantry - ofcourse, just an order of magnitude or two more complex

Edited 2 time(s). Last edit at 09/16/2012 03:58AM by proto.

... you should read through the threads to paste-dispensing and laser-diodes ... especially the older posts contains many usefull information to this sort of applications ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Do you know anytihng more you can share about these nozzles? I've look around and never found any description of system that deposits powders. Can they do overhangs?

God that is so cool - [www.youtube.com]
$,$$$,$$$ = "power is typically 500W - 6000W"..."Helium is used for the powder stream" ... something based on friction. Confusing still but cool.

I am trying to make a powder dispenser. Do you think the reprap printers would benefit from a cheap one, maybe they could do powdercoated plastic or even begin to attempt DMD? Or is this too crazy

So I've researched as best as I can, and there is prior art, but nothing good enough for reprap to use TODAY like buying 1.75mm conductive filament.

Wouldn't you all thing the best solution is a filament that can be printed the exact same way you current print, so it has no additional hardware or mechanical complexities? Think about all the things you can print...I might turn this into my next project.

Using static is a possibility, I experimanted with inducing static onto a sheet of acrylic with an ioniser and metal powder
was attracted to it, I drew some text and it was clearly visable, but this approach has many limitations.

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Random Precision

Hi John,

What was your goal? And what were the limitations? Cool approach.

I think it would be cool to make an automated chakpur. (A chakpur is the tool that monks use to deposit sand when making a mandala sand painting.)

>I think it would be cool to make an automated chakpur. (A chakpur is the tool that monks use to deposit sand when making a mandala sand painting.)

:-p See..I always knew people would come up with something I never even knew existed to used this for...hahahah. Can you think of anything more mainsteam? I was thinking a beverage art printer...cake, beer, toast, etc.. like onlatte but powder (much harder).

MattMoses Wrote:
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> I think it would be cool to make an automated
> chakpur. (A chakpur is the tool that monks use to
> deposit sand when making a mandala sand painting.)


:-p See..I always knew people would come up with something I never even knew existed to used this for...hahahah. Can you think of anything more mainsteam? I was thinking a beverage art printer...cake, beer, toast, etc.. like onlatte but powder (much harder).

... when working with powders (ceramic and gold/platinum) I've mostly mixed them with a fluid, so it was a dispensable paste.

For glass-sealing the glass-powder is mixed with aqua dest. to a slurry, set with a tip or though a needle on the place to seal/bond and heated to around 400 centigrades, so all the water will evaporate and the glass-powder fused to solid glass ... the same with some hard-soldering alloys.

Pure powder is commonly only used in powderbed-printing or for the linked methode of blowing powder in a hot spot, so it will melt and form a blob.

By the way - with dark thermoplastic powder (or glass or ceramics, with low melting temps) you can realize the same process as shown in the youtube-video with cheap IR-diodelasers and without need of inert atmosphere

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Maybe have a tube feed the powder and drop it onto a shaped vibrating plate, powered by solenoid or peizo??????????,
I think it would lodge or bridge if you try to pass it shrough a hole without a carrier fluid.

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Random Precision