Well as of recently, I've been working on designing a pneumatic stepping motor called a wobble motor for Darwin. For an explanation of how a wobble motor works see here(site appears to be down last time I checked): Or if you have an IEEE account see this: Wobble motors have high torque and high resolution so it certainly It seems like we could certainly make one that meets Darwin's requirmenby Gene Hacker - Mechanics
Cris, how did you make an electrical connection to the metal did you just clip a wire to it? IE, if you wanted to cut concentric circles how would you cut them?by Gene Hacker - Mechanics
Seems NASA is experimenting with tool-changing hexapod robots:by Gene Hacker - General
Typically, they use nylon powder in SLS systems. At my university, I believe they make the nylon powder for the SLS machine by ball milling larger nylon shavings. I don't think a DVD laser would have enough power to fuse plastic powder, at least not very fast, as a CO2 laser is typically used.by Gene Hacker - General
Viktor, you might look into using colloidal silica, IE silica with particle sizes on the order of nanometers. Though if you use colloidal silica, you might have to dilute it a bit, as colloidal silica solutions behave as shear thickening fluids and are actually being investigated for use in body armor. Though, I've heard of it being shot through inkjet printer cartridges just fine.by Gene Hacker - Plastic Extruder Working Group
Forget about the tube, I'd be more interested to see if one could make the optics for the tube. FYI, low end laser cutters use about a 25 watt laser, I found a 25 watt laser diode on ebay for about $100.by Gene Hacker - General
SODIUM ALGINATE! You can buy big bags of the stuff from art stores real cheap, it's used for making molds or something of that nature. Looks like we might have a keeper here...by Gene Hacker - Plastic Extruder Working Group
Consistency of yogurt you say? Do you mind explaining exactly what ceramic slip is? Shrinkage can be a very good thing or a very bad thing, depending on whether or not it shrinks uniformly.by Gene Hacker - Paste Extrusion Working Group
Viktor, a foam cutter might be extremely useful. This might be especially useful for producing metal parts via foam casting. Perhaps one could design a soldering iron holding chuck that reprap could use for this purpose.by Gene Hacker - Mechanics
Why not just print the parts to a tea making machine instead?by Gene Hacker - 3D Scanners, Book Scanners, and Optics
Combine one of these with a hammer and a reprap, and you have a simple "teleporter." Scan an object in with the scanner, destroy it with the hammer, then print it in a different location with a reprap.by Gene Hacker - 3D Scanners, Book Scanners, and Optics
Well I have heard you can electroplate copper onto zinc galvanizing spray. Might be useful for spray on n' plate circuit board fabrication.by Gene Hacker - Plastic Extruder Working Group
Here's the artist's webpage translated from Japanese: Also the escher 3d fish bird and lizard cube tesselations might be interesting to print once we get color working.by Gene Hacker - Let's design something! (I've got an idea ...)
Stratasys SST's don't use really use an acid bath to dissolve support material, they use a strong base bath, specifically NaOH(aka lye). Forrest, you should try to dissolve 60% marble dust PCL with acid(vinegar might work).by Gene Hacker - General
Wait a minute, you have to pay to read the article? I can read it just fine and I don't have a subscription. Here's the link: I am by no means trying to sell subscriptions to whatever website that is, this was simply the first link I found involving PCL cell-scaffolding made via FDM(3d-plotting as they call it). Surprisingly their printing system has about the same trace-width of reprap(~0.5by Gene Hacker - Tissue Engineering
Reprap already prints PCL and PCL is used to make tissue scaffolding, so yes.by Gene Hacker - Tissue Engineering
I have tried to do 3d-printing with sodium acetate made from vinegar and baking soda. The only problem is that the sodium acetate started to crystallize before it cooled down and I could start printing with it. However, you might get better results if you use 'clean' sodium acetate. After sodium acetate cools it's hard, brittle, and water soluble. Hydrous sodium acetate also 'melts' when you heatby Gene Hacker - General
So, the more steps the stepper can make the more accurate it is? How accurate can RepRap get before adding more stepper steps stops making a difference?by Gene Hacker - Mechanics
Why not use another type of plastic as support material? Such that the print plastic sticks but does not weld to the support plastic, so that it is easier to breakaway. Or is there even such a plastic? Hears some detail on the support material(fast forward to 2:08): Apparently Dimension BST printers are capable of printing ball-bearings:by Gene Hacker - Plastic Extruder Working Group
Does the Austin self-repper group still exist? How is the ACTLab reprap going or does it even exist?by Gene Hacker - Texas, Austin RepRap User Group
So how much does reprap cost without the printed parts? I happen to have very cheap access to a laser cutter at the moment.by Gene Hacker - General
So the hole in the bed isn't always filled with the doctor blade? This might be useful as an attach point for "tool beds." For example, you could have a tray with a bunch of SMT components that attaches at that point.by Gene Hacker - Mechanics
I think you are refering to shape deposition manufacturing. Placing a nut or linear bearing actually seems like a pretty good idea. You can do a whole bunch of cool things with SDM:by Gene Hacker - Paste Extrusion Working Group
What about using steel cable(the thin type) or wires instead of plastic straps? Possibly using multiple cables on the same diagonal for extra strength.by Gene Hacker - General
I mean is it possible to practically adjust the temperature and the rate it changes so you can go through various sinter cycles?by Gene Hacker - Casting and Moldmaking Working Group
Polysaccharide binder is most definitely sugar. Perhaps a similar mixture could be used a reusable support material. BTW is there anyway to adjust the temperature of a microwave kiln?by Gene Hacker - Casting and Moldmaking Working Group
You'd need something bigger than fish tank tube, it might get clogged too easily. A better option might be to spray water on the milling head to prevent copper dust from getting in the air like they do with rock cutters. Although spraying water brings up some more problems... Crackpot idea: negatively charge the board and put a positively charged plate on the milling head to attract away the neby Gene Hacker - Plastic Extruder Working Group
This new toolhead allow RepRap to manipulate surface mount components. If a milling head and solder paste dispenser could be added to RepRap then production of the required PCBs could be fully automated(except you'll still have to solder on the non SMT components). How it works: a small vacuum pump creates suction in the blunt tip needle to pick up SMT components and the gear motor rotates the cby Gene Hacker - Pick-and-Place Electronic Assembly (and robots!)
If you just need to supply some sort of adjustable tension why not use nylon cord? It's fairly cheap, $3.95 for 50 ft, with 300lbs load capacity:by Gene Hacker - Mechanics
Others have been able to successfully mill PCBs: Only problem is milling head vibration, which is a problem that is easily solved. The question is, is it cheaper to produce blank boards or to buy them?by Gene Hacker - Plastic Extruder Working Group