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Brian
Is .050mm asking to much, the body can be about m6, 6mm long, but the final dimensions will depend on community effort.
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johnrpm
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General
Going back to the head after 24 hours, it fired up straight away, no problems, it always needs a few extra volts for a second or two and it will stop and start from then on, but I read that the researchers had the same problem, the only issue at present is the jet is not perpendicular, it is at about 10 degrees, I smoothed the front with fine wet and dry, maybe a tiny particle embedded in the sol
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johnrpm
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Powder Printing and Selective Laser Sintering
I have seen dashboards made on a SLS and covered with foil, it looks exactly like wood, football players already have custom fit insoles, why not everyone?, ear phones that do not hurt after a while, reading glasses that don't hurt your ears, garden tools, the common thread is a scanner and 3dprinter.
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johnrpm
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General
Apple have come up with a fantastic business plan, the Iphone is good so I am told, but its the apps that make it so desirable.
A hardware equivalent to apps perhaps???, custom fit is one area that is spoken of, an insole for your shoe made from a scan of your own foot rather than factory made to the average person, etc,etc
Edit, Sorry, I have just repeated what others have said above, must rea
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johnrpm
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General
What is the smallest size hole you can do?, I am playing with printheads and although we do not have a final design yet, it will be a small hole.
by
johnrpm
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General
This morning after an hours rummaging, I found a small bleed valve, fitted it to the head and blead all the air from within, whilst fiddling around to get the jet going air appeared, thee are two possible reasons for the air, my fittings are not air tight or the ink is de-gassing, I shall refit with silicone and try again when time permits.
I have made three heads, all the same but different dep
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johnrpm
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Powder Printing and Selective Laser Sintering
I have a vacuum pump so could build a rig for degassing, I bought the ink from poundland some time ago, its for re filling printheads, I have used 2 bottles of magenta and am using yellow now, I hope that we do not need to de-gass as it will make things less appealing, but at the moment I can not find where the air is coming from, sometimes its best to walk away for a while and come back with a
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johnrpm
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Powder Printing and Selective Laser Sintering
Madscifi,
Well done for finding all that info, They look very similar to what I did, and I thought I was being origonal,( nothing new under the sun), at least it proves we are on the right track.
I am testing different acrylic bodies, (your excellent idea) , I am having a lot of problems getting rid of entrapped air, even a small bubble when subjected to vibration becomes froth
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johnrpm
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Powder Printing and Selective Laser Sintering
I have tried the active nozzle idea, drilled the piezo disc, suspended the tungsten wire through the hole and tied on a 12mm nut to tension it, soldered the hole, filed down the solder blob to make it flat then pulled out the wire, then realized I had to seal the active side.
I used nail varnish as the sealant but could not risk blocking the nozzle hole, I turned an acrylic body to hold it and se
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johnrpm
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Powder Printing and Selective Laser Sintering
Thank you Viktor, those drivers look very good.
At present we have no more than proof of concept, and lots of work to get it plug and play, but I can not help thinking ahead,
do you think it possible to detect from a feedback signal whether the printhead is printing fluid, I was thinking that the drive could go through a set routine to establish optimum frequency and voltage automatically at sta
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johnrpm
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Powder Printing and Selective Laser Sintering
Here is the key finder enclosure as a OBJ 3d model, it seems that it is designed to maximize the sound output from a low voltage supply, so may indicate the shape for our printhead cavity?.
Sizes in a jpeg
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johnrpm
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Powder Printing and Selective Laser Sintering
The 20mm piezo's arrived today, When the 25mm clear acrylic rod arrives I intend to make a selection of bodies, with shallow, deep, flat bottomed, conical cavities, although I have no means of measuring the effects other than how well it works, (assuming it does)
But first I have a plan so cunning that you could put a tail on it and call it a fox, (black adder)
I want to make the piezo disk serv
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johnrpm
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Powder Printing and Selective Laser Sintering
So many things to try, which is part of what makes this an interesting problem...
I agree, its an area where few have been before in comparison to some other things.
based on your descriptions I think I need to spend more time trying to get the device to generate a controllable stream before I try getting it to generate single drops. A higher voltage, either directly or via a transformer betwe
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johnrpm
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Powder Printing and Selective Laser Sintering
Could I ask the reprap community for your thoughts,
I have been considering the effects of the fluid chamber in front of the bimorph, its size and shape.
Today I was cutting some 40mm square thin walled tube, the cut off saw is old, with a HSS blade running at 60rpm with 20tpi,
cutting fluid had run into the tiny gap between the tube and backjaw, the fluid was shooting up about 50mm due to the
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johnrpm
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Powder Printing and Selective Laser Sintering
I also could not get it to work with 30 volts through the tip132, and have gone back to the original drive until I fully understand what is happening, last night I paid more attention to what was happening, the best way to describe it is like a neon lamp, It needs a striking voltage and frequency, and when it is running the voltage can be lowered to 20volts or slightly less, but I do not yet full
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johnrpm
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Powder Printing and Selective Laser Sintering
This is a key finder purchased from poundland, when I first saw the cover over the 20mm bimorph I thought it would need removing, but realized that this could form the housing, with a thick walled tube glued with epoxy over the hole, and drilled to take a syringe tube for the fluid feed, then glue a shim nozzle over the front of the tube, it should be possible to do it without a lathe, just a pi
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johnrpm
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Powder Printing and Selective Laser Sintering
I am now sure that the main problem I have been having is the air in the head, today I spent some time getting it to work, the only way was to have it upside down whilst fiddling with the dials, when I touched the head I could only feel a small vibration, but the feed pipe vibrated a lot, this indicates pipe hammer mentioned, I installed a small grubscrew with a point to let the air out but still
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johnrpm
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Powder Printing and Selective Laser Sintering
Casainho,
email me your address and I will send you the printhead, I am sick of seeing it at the moment, this morning I put the finishing touches to the board,I had a problem with the mosfet, 5 volts on the gate would not trigger it so after some head scratching changed it for a tip132, then it worked.
I ran the head with the normal drive to ensure all was working well, then connected the head to
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johnrpm
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Powder Printing and Selective Laser Sintering
I have built a board that combines both circuits, a simple mosfet (IRF510) suggested by Cashainho, also the H bridge suggested by Slavko and interpreted by Madscifi, thanks again for doing it, I would never have deduced it all, so I can do both, just need to check all connections and programme the arduino, I tried the method for small holes suggested by Slavko, I used tungten wire .002" diameter,
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johnrpm
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Powder Printing and Selective Laser Sintering
I have a bag full of old HP printheads, the Zcorp gets throught a lot, on the bottom is a foil with the nozzle array, I wonder if I could remove this
and stick it to my head and block the unwanted holes????????,
She who must be obeyed is taking me to Ikea now, more DIY.
edit, I have some signal mosfets in stock that should work.
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johnrpm
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Powder Printing and Selective Laser Sintering
I have played with it, its very fast and user friendly, never used the gcode though, Skeinforge has more tweeks and settings at present but as it evolves?.
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johnrpm
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RepSnapper
Thats interesting stuff from Slavko,
Trace seems a way to wide. For PCB I think 0.2mm is max alowed.. So the
nozzle should be aprox 0.08 as spot is over 2 times larger than orfice
Nozzle needs to be close to paper, the way printers are made, I was just waving the paper about..
The other 'thing' is that I see continous stream. Is it capable to make
only one drop? Ie is it reliable if you appl
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johnrpm
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Powder Printing and Selective Laser Sintering
Sorry for the delay in replying, been busy doing DIY,
I would prefer that you say/verify that 0.1mm line thickness can be done with this print head :-)
Not as it stands, I have not created a .1mm nozzle, but I see no reason why it would not be possible.
Can you make holes of 0.1mm? Do you think that with a 0.1mm hole we can get a 0.1mm line thickness? we can't get lower thickness lines than
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johnrpm
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Powder Printing and Selective Laser Sintering
Thanks for doing the wiki stuff, that really helps,
the line is thick because the head is at max power, the nozzle diameter is approx .2mm,
the drive electronics are very important to the head output, also the distance from the nozzle to workpiece and velocity of workpiece, ages ago when I dismantled an hp printer and told it to do a test print whilst holding the printheads by hand, I was amazed
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johnrpm
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Powder Printing and Selective Laser Sintering
I did the video early this morning and am figuring out how to add it, I see that vimeo is used by others, I just can not bear to have anymore logins and usernames, the video is rubbish but should give an idea,
Madscifi, I hope it comes up to expectations for what you want to do, it needs a lot of development for the intended application, some applications need dots whilst others need jets, I thi
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johnrpm
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Powder Printing and Selective Laser Sintering
I have been putting in a kitchen worktop today so have not had much time, but have set things up to do the video tomorrow, one thing worth mentioning is the relative height of the printhead and reservoir, by getting the reservoir at the correct height it avoids the formation of a small dome of ink on the face of the nozzle, which is blown of when the printhead is turned on.
About the circuit,
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johnrpm
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Powder Printing and Selective Laser Sintering
Update,
I made a new body using the syringe end, it does not work, the gap between the tapers, about 2mm spoils the flow, whilst fiddling with the dials and watching the void space, I could see the fluid turbulating but not getting out of the needle, I may revisit this at some point but have changed it to take a tapered insert, I drilled a .3mm hole in the insert and tried it, worked straight awa
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johnrpm
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Powder Printing and Selective Laser Sintering
I think I may be able to get the bottle stl, give me a week and I'll post it
by
johnrpm
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General