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> > casainho Wrote:
> 0.343mm? -- it's nice to know you can drill such
> small hole, because before we would need to pay
> $150 for 10 nozzles of 0.25mm just for try make
> the same you just did :-)
0.050mm not 0.25
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johnrpm
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Powder Printing and Selective Laser Sintering
Thank you once again Madscifi,
I can only agree with all you have said, For ink a hacked printhead would be faster to deploy, thats why I have tended to concentrate on higher energy units for higher viscosity materials, I found myself collecting the parts for the laser printhead, but realized that it may not cope with higher viscosity ?
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johnrpm
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Powder Printing and Selective Laser Sintering
Thank you Madscifi, for showing the circuit, I think you are right about not needing q3 and q4 if a signal level mosfet is used, but belt and braces never hurts.
A thought about the high voltage problem, by having 2 piezo disc's back to back, (mentioned earlier) and mounted on a thick walled tube with the feed and nozzle on the periphery, in theory it should double the displacment for a given vo
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johnrpm
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Powder Printing and Selective Laser Sintering
Great news, looking forward to seeing the pictures, it seems to take me 2 hours to document every 1 hours work,
can you give some detail about the power supply also please.
edit, is that pure water, if so well done, I could not get water to work
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johnrpm
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Powder Printing and Selective Laser Sintering
So far I have not tried too hard to create single drops, but had the idea to use a laser some time ago, and want to encompass as many ideas as possible, the mistmaker is a piezo unit and small lasers are reasonably cheap.
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johnrpm
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Powder Printing and Selective Laser Sintering
I look upon Reprap as a research and development environment where ideas, problems, solutions are discussed and acted upon, and this has spawned spinouts, directly or indirectly, but I do think that Sebastien has done a marvelous job in opening up the whole site to be as all inclusive as possible, and hope to see it continue as a research type place.
We are here for enjoyment, to share interesti
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johnrpm
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General
Would any glass do, or would soda glass be better, I shall also try a mistmaker, see wiki page, it could melt plastics and silicone rubber, so may have enough energy.
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johnrpm
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Powder Printing and Selective Laser Sintering
I did extract the foil from a HP11 cartridge, but under the microscope has a backbone running down the middle, I assume the heater part, so made it less attractive for gluing onto a body, other cartridges may be better?, I did scrounge some glass micro pipette's, about 6mm dia tapering down to ???, less than 1mm, haven't measured it, I hope to try them as spark unit bodies, but the long taper is
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johnrpm
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Powder Printing and Selective Laser Sintering
Untill now piezo print heads have been the domain of university researchers and commercial companies, but if you would like to take of your shoes and socks, and paddle in the sea of piezo here is a way.
Here is a thread about nozzles, they are fundamental to the head and can be a major drawback to people without machines of any kind to make them, also the body would need a lathe or miller availa
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johnrpm
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Powder Printing and Selective Laser Sintering
Thanks Nophead, that makes sense and would explain why when adding a clamp to the disc I had to drive it harder to make it work.
Do you have some head you can send me? can I send you my address?
I am hatching another cunning plan, will post tonight now I have recieved a PM.
P.S I ordered the cold cathode drive and trigger transformers from Rapid at 4pm yesterday, they arrived at 10;30 this mo
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johnrpm
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Powder Printing and Selective Laser Sintering
Not sure if this helps or not, some HP printers have a fringe strip and pickup, also would optical mice, or the camera in them be any good, I think I saw something on the arduino website, you would not need a fringe even with this, just a flat strip, that is if the resolution is good enough.
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johnrpm
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Controllers
I do not know enough to know the answer, but if we tap a bimorph we get a voltage output, and as we are tapping it electronicaly I thought that its own output may be adding to the signal, if you know what I mean, as in the piezo transformers.
Edit, If I try it with a bigger transformer would that tell us something???.
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johnrpm
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Powder Printing and Selective Laser Sintering
I ordered some trigger transformers but noticed the cold cathode supply and thought for the price it was worth a try,
last night I wired up a trigger transformer salvaged some time ago whilst waiting for the order to arrive.
the input voltage was 10 volts from the function generator and at the bimorph 80 volts from the trigger transformer, with no other componants in circuit.
It powered the buz
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johnrpm
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Powder Printing and Selective Laser Sintering
looking on the steminc site here piezo transformer
it says a step up ratio of 40,Am I right in thinking that they are what they say they are, ie, a transformer, interesting.
I have ordered one of these to see if it will drive the spark units, cheaper than buying the components.
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johnrpm
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Powder Printing and Selective Laser Sintering
This may help if you have not already seen it, strucured light source code and binary
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johnrpm
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Experimental
Sorry Viktor, I miss understood, some plugins in imageJ use the narrow depth of focus of microscopes to construct a model,
I have been searching for free or affordable software for some years to construct models from stereo pairs, but have not found anything good enough, photosculpt is good at some things and I was impressed with some results, but is only good at shallow depths, I did play with a
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johnrpm
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Experimental
Viktor,
Have you looked at imageJ, if I understand correctly you want to construct a model from image stack?, also mimics is a commercial software for the purpose but very expensive.
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johnrpm
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Experimental
Thank you for doing this, looks like a great deal of effort on your part, look forward to trying it out
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johnrpm
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Experimental
Thank you for the usefull advise, I will try to digest it, I have never heard of a long tailed pair so would need some help with resistor values etc, do you think that low energy lights, or the inverter inside would be of use, I am trying to find common items that most people can use, not sure about the USA versions though.
P.S I see your update caused problems, mine disabled the sound card, n
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johnrpm
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Powder Printing and Selective Laser Sintering
Interesting info on tube amp transformer winding. here
What about voltage multipliers here
Question, could we condition the output of the transformer in some way, a clipper or such???.
The thing that started me using a transformer was the cycle buzzers, thats how they had done it so I copied them, they were very loud.
I have seen trigger transformers used also, which may be cheaper.
I know
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johnrpm
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Powder Printing and Selective Laser Sintering
Great news, glad your persistance has paid of, your mains supply is 120volt whereas in the uk its 240volts, so transformers here would have a higher ratio, I dismantled my drive to give you some info on the transformer, it has multiple tappings but the resistance is 1.3ohm input and 300 ohm output , I know this is not a true indication because they could have used different size wire for differen
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johnrpm
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Powder Printing and Selective Laser Sintering
Madscifi,
Thank you for sharing all that info.
[*] Suggests that a minimum drive bandwidth of 1 MHz is required.
I may be talking rubbish here, but I wonder if the bimorph, as it is a metal disc, can physicaly move at very high speeds compared to other types of pzt???.
I bought a function generator yesterday in kit form and got it working this morning, it can produce, sine, squa
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johnrpm
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Powder Printing and Selective Laser Sintering
Here are STL and OBJ 3d models of the spark units, also some images.
I intend to make a housing to hold a pair at first, with some provision to preload onto the tube, then try the bank of three to see if that works, the tube will be anything I can get hold of, from stainess to rubber.
As mentiond before, when connected to the existing drive, very small amplitude can be felt compared to the bim
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johnrpm
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Powder Printing and Selective Laser Sintering
Yes the nozzle is brass, screwed in with a small O ring to seal the face, the plan was, to have the same nozzle with different bodies to evaluate any differences, but the papers you linked to answered my questions, " larger chambers damp oscillation" so higher frequencies can be used, this also applies to longer feed pipes.
That is assuming I have understood it correctly, there is little point in
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johnrpm
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Powder Printing and Selective Laser Sintering
Madscifi,
I shall answer all your questions in chunks, by editing this after getting the info or pictures to explain things.
1. What material is the current printhead made of? 25mm acrylic rod, (see picture )
2. What did you use to attach the piezo to the body? superglue
3. Can you provide a link to the 20mm piezo that you are using? here
3. What is the diameter of th
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johnrpm
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Powder Printing and Selective Laser Sintering
8mm hex would be ok, as its early days in development its hard to say how many would be needed, I realize you need to know if its worth tooling up for, Can I turn it round as ask what is the minimum quantity you would be prepared to do, and a ball park price?.
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johnrpm
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General
The nozzle at the bottom has few critical dimensions, instead of m6x6, m5x5 would be ok, the only thing that may need
to be accurate apart from the nozzle hole may be the land diameter on the front face, this apparently effects wetting but
I can not give a size as yet, so flat fronted for now.
Brass would be good for hot wax but polymer should be ok for inks I think, when I play with waxes in ma
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johnrpm
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General
We are trying to develop a printhead here
not molten polymers but resins, waxes etc, still needs a lot of development, but if we succeed most people will need nozzles.
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johnrpm
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General