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Re: Printer idea: selective melting of a material with freeze thaw hysteresis - 11 years ago
Here for instance, I wonder how much the hysteresis is changed by the addition of this protein, the doc says some, just to show there are some substances that might work forth this: Ultimately though a material that melted and thawed at a higher temperature, and then just run everything at a higher temperature, and was water soluble or something, might be better, because if say the melt/freezeby GreenAtol - General
Printer idea: selective melting of a material with freeze thaw hysteresis - 11 years ago
I hope this is an ok place to put this, but I just had a very interesting idea. Almost all materials have a freeze-thaw hysteresis. I forget what it is called, but even ice has this. Suppose, for instance, it melts at 0.1 degrees, and does not re freeze until -0.1 degrees. So suppose you had a block of transparent, bubble free ice in a very precisely controlled chamber, at very close to 0 degreeby GreenAtol - General
Printing directly with a peizo inkjet print head - 11 years ago
I was thinking of trying to print with PVA in a solution as an ink with my inkjet printer. But there are 2 kinds of print head; thermal and peizo, which uses mechanical pumping action. The peizo is probably the only one it would work with, I would think, as with a thermal print head non volatile residue would accumulate in the print head. How can you tell if a print head is peizo or thermal?by GreenAtol - General
Re: Vacuum Chamber - 12 years ago
Guys, don't forget the important possibility of using a high vacuum inside the electron gun, but only relatively low vacuum in the print chamber. I remember calculating, I think the results should be on the wiki (see my edit history if you are desperate, don't have time to do it again though sorry) that the beam spread was not a major problem actually at low vacuum. Especially because the beamby GreenAtol - MetalicaRap
Re: The quest for a promising metal printer continues... ultrasonic consolidation - 12 years ago
It sure would be a good start to get access to one of those machines though. Hey If they're not competitive I wonder if there are any laying around out there not being used? Man that would be a flying start to get a project to develop such a printer off the ground. We could start experimenting with support materials right away!by GreenAtol - General
Re: The quest for a promising metal printer continues... ultrasonic consolidation - 12 years ago
yeah, I think the first doc uses said company's machine. They don't use support material though. That is the main innovation we need. Plus cheaper and way smaller. The support material allows us to get around the 1:1 height:width ratio and also to start leaders which their machine cannot do.by GreenAtol - General
The quest for a promising metal printer continues... ultrasonic consolidation - 12 years ago
Ok, so you may have heard of ultrasonic welding. Basically two metal surfaced are rubbed against each other at ultrasonic frequencies, and amplitudes in the 10-20 micron range, under high pressures (it was ~1500-1800 newtons under a roller but not apparent what the area under said roller effectively was, the length of the roller can probably be found in those docs). So what Ultrasonic consoby GreenAtol - General
How's progress on Metalicarap? - 12 years ago
It looks like things have stalled. Actually it seems like maybe the goal was just way to high here. It's the same mistake that Stallman made when developing GNU; try to do things super well the first time even if it takes forever, and it costs too much and takes too long and net result is nothing gets done I'm afraid. I think maybe a mini version would be a good intermediate step. People don'by GreenAtol - MetalicaRap
Re: Printing a cast-forming material with a peizo inkjet printer? - 13 years ago
oops I meant SIS, selective inhibition sintering, not SLS, selective laser sintering.by GreenAtol - General
Re: Printing a cast-forming material with a peizo inkjet printer? - 13 years ago
Hm, that might be a good option, but radiant heating cannot achieve possibly a higher temperature than the radiant element, and indeed will necessarily achieve much less. I know sls machines can do copper which melts at 1086 deg c though (or maybe it was a copper alloy that melts at lower temps...) ... What sort of resolution and accuracy do you get with sls? Do you get full density parts? I wby GreenAtol - General
Re: Let's talk about printing in full strength metals 
- 13 years ago
Also building at 900 deg c is not exotic. It's what electron beam melting(EBM) printers do. The print bed is held at 900 deg c.by GreenAtol - General
Re: Let's talk about printing in full strength metals - 13 years ago
I don't think it would be that expensive actually. Ceramic circuit boards for examply are low cost, so a plate of ceramic is not that bad. The process for producing such a print head would be much like the process for producing hybrid ceramic multilayer modules, which are commonly used in, for example those can-type crystal oscillators (xtals). Basically you would me making a multi layer ceraby GreenAtol - General
Re: Printing a cast-forming material with a peizo inkjet printer? - 13 years ago
??? how are any of these things printing in a cast material? The wax I can see and that is a good one, you could make a wax object and then do lost wax casting. But I'm talking about printing the cast directly. I know there are many other methods, but at some point you gotta pick something and look a little deeper, instead of always jumping from one option to another. I looked up some saltby GreenAtol - General
Printing a cast-forming material with a peizo inkjet printer? - 13 years ago
Ok, so some print heads for inkjet printers us peizoelectric pumps, and get resolution and accuracy in the micron range. If we can use them to print in a material that can stand high temperatures then they could make casts, a highly useful application. Perhaps if a material could be found which was carried in a solvent? The droplet hits the surface in the solvent, which then evaporates, leavinby GreenAtol - General
Re: Let's talk about printing in full strength metals - 13 years ago
The stated goal of the reprap is to make a santa clause like machine that can make practically anything, including itsself. Exactly how do we expect to get there by farting around with flimsy plastics printed at crappy resolutions?by GreenAtol - General
Re: Let's talk about printing in full strength metals - 13 years ago
Steel melts at 1538 deg c.by GreenAtol - General
Let's talk about printing in full strength metals - 13 years ago
Ok. So a while back I put a lot of stuff on the wiki about printing in full strength materials, especially metals, which you can find through the index page. I'm thinking of the most promising approach I have encountered thus far: a small print head with an array (say 1000 by 1000) of ceramic electrostatic valves/pumps that release droplets on demand of a)molten steel (let's suppose tool steelby GreenAtol - General
Re: The Future Is 3D - 13 years ago
PFF, why don't you try to stop us, asshat.by GreenAtol - General
Re: Reprap.org's current mininum website value is $3,136,875 - 13 years ago
Cough, sputter. Adrian, we are talking about the domain name, and as I said you can put it in the sale contract that a link forwarding to the reprap project remain on the page, so the sale of the name does not damage the project's public accessibility significantly. If you would turn down the benefits to humankind that $1 billion, when used for the right things, as it would be if given to thisby GreenAtol - General
Re: Reprap.org's current mininum website value is $3,136,875 - 13 years ago
that's what I said. if they are doing things accurately, then the 3 mill number is what someone is willing to pay for domain alone- in isolation. This needs further investigation: someone should ask around/test the waters at afternic or godaddy or other domain name reselling places. We should put it "up for sale" and see what bids we get (of course we don't have to accept them, just to find aby GreenAtol - General
Re: Reprap.org's current mininum website value is $3,136,875 - 13 years ago
No, by definition the market value of something is what someone else is willing to pay for it. Now it may be that this site is inaccurate though. But by definition, if that is the worth of the domain, that amount of money can be obtained by selling it.by GreenAtol - General
Re: Reprap.org's current mininum website value is $3,136,875 - 13 years ago
If this is true, we need to seriously look at simply hopping to another domain name, and selling this one with the requirement that a small note always be present on the new page saying "looking for the reprap project? click here". Seriously. Who would pay 3 mill though? I doubt anyone would. But 3 mil would be a massive boost to this project and be well worth it to hop domains..by GreenAtol - General
Re: Whats special about the goal of 'reprap' vs existing capabilities/realities like CNC milling machines - 13 years ago
Yes, you have some good points and this is mentioned in many areas on the reprap site already. Search the forum for my posts "thoughts on a truly practical printer" or something like that I forget the exact title, where I talk about this. Basically it is not about qualitative differences so much as quantitative. The capital costs of the set of production equipment you want has to go down. Fleby GreenAtol - General
Re: Metal FDM thread - 13 years ago
Search the wiki for "metal printer" and you will find a ton of stuff I have put up on printing with metal and other full strength materials. In short, it can certainly be done and has been in a number of projects, and is not hard either, if you just want a crappy object of rough shape. but making really useful stuff (good dimensional accuracy and low residual (internally equilibriated) stress iby GreenAtol - General
How to relieve or reduce stress in metal deposition? - 13 years ago
I posted a thread up at the ultmaker newsgroup here : Any ideas on this problem?by GreenAtol - General
Re: Ultrasonic isostatic consolidation with block printing, or "digital materials" for a really awesome multi material printer - 13 years ago
Hey yeah that sounds interesting. The main problem is bonding like I said. Maybe you could use Xrays or something to weld other materials - all materials have resonant frequencies at which they are opaque, and frequencies at which they are transparent. If the upper (or side or bottom layers as you could send the beam in there from the side) were all transparent at suitable frequencies for allby GreenAtol - General
Re: Ultrasonic isostatic consolidation with block printing, or "digital materials" for a really awesome multi material printer - 13 years ago
I can't believe you guys, this is the closest thing there is right now to realizing the ultimate goal of the reprap project, and all I get is crickets chirping.by GreenAtol - General
Just take a piezo based inkjet printer and add a solution to print in 3d ? - 13 years ago
I was just wondering, and I have not been able to find this on the web, has anyone tried just taking an old printer with piezo head (like and epson apparently according to the inkjet printer wikipedia page) and just loading it with a solution of say sugar or some other more suitable material? Droplet goes on the surface, water evaporates, leaves deposit. Repeat. Would take a while to print sby GreenAtol - General
Ultrasonic isostatic consolidation with block printing, or "digital materials" for a really awesome multi material printer - 13 years ago
Okay, this is a sort of "best of" idea from the library research and thinking I have been doing. Neil gershenfeld and friends have a patent on a printer that can use" digital materials" essentially really small blocks that fit together and come apart : . Interesting. However the problem is that the object would not be very strong or dense with the method shown. However you could modify thby GreenAtol - General
Re: Progress on (library) research on the metal deposition head/the other metal printer - 13 years ago
no interest?by GreenAtol - General
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