Someone made a microfluidic device by printing a pattern on a Shrinky Dink, shrinking that, then using it to mould the channels. I can't help thinking that there's an idea there that needs to be expanded upon. (no pun intended)by degroof - General
This morning, I tallied up the costs so far and came up with about $800. That's buying pretty much everything, rather than scrounging, molding, milling, etching etc. All that's left are the RP/moulded parts and maybe a few odds and ends. I figure total cost will be somewhere in the region of $1200 by the time I'm done. Rough cost breakdown: $100 - Electronic components $300 - Mechanical partby degroof - Reprappers
I'm also waiting patiently for the parts to come available. I've got an extruder kit on order, so that'll occupy my time for a bit. I should also update my boards to use the latest firmware.by degroof - General
I would expect the first RepRapped RepRap to be made by either: - Adrian's team using the original Darwin - someone who builds a Darwin from moulded parts, then replaces them one by one Then there's also the first RepStrapped RepRap. That's pretty much anybody's game at this point. Hmm, does a Darwin made from moulded parts count as a RepRap or a RepStrap?by degroof - General
When I think of rapid prototyping, I can't help comparing it to clay sculpture. No sculptor in their right mind would build en entire work out of tiny threads of clay. It'd take forever. What they do is rough in the general shape, then add and remove bits, refining the shape until they get the desired result. The machine equivalent of this would be something with three heads: 1. a high-volume exby degroof - General
See, the reason I'm thinking along these lines is that, given the current extrusion rate, it would take 5 days of continuous extrusion (not counting breaks) to produce all of the rp parts for a RepRap. That's based on the parts being roughly 1000cc and an extrusion cross-section of 0.25 square mm. The RepRap build volume is a 30 cm cube. Just for fun, I calculated the time it would take to fillby degroof - General
TheGuy Wrote: > So how about you stretch out the extruder, making > it a line instead? A wide, thin nozzle like those > used by cake decorators to make flower petals. > That way you could lay down much more line at > once. By placing movable blockers, solenoid pins > for instance you could split or narrow the > extruded ribbon. A single point extrusion would > just be a suby degroof - General
Now, that'd make an interesting art installation. A RepRap prints out random objects, which are then picked up, put through a grinder and fed back into the extruder.by degroof - Reprappers
nophead Wrote: ------------------------------------------------------- > The limiting factor is the grip on the incoming > filament. If I go too fast it strips the thread it > has cut. A shorter hole in the nozzle would help a > bit. How about a continuous taper on the internal bore? Basically eliminate the "shelf" altogether. > Temperature has liitle effect on flow rate once &by degroof - General
> Alternatively, one adjustable size nozzle. That brings up an interesting problem: Wouldn't a variable line width imply a variable layer height too?by degroof - General
Seems like the limiting factor on the RepRap -- on any FDM machine -- is the extrusion rate. The axes can move a lot faster than they do now but the plastic comes out at only, what, 10 mm/s or so? So, say you have a RepRap all assembled, tested and extruding at 10 mm/s. What would you do to "overclock" it?by degroof - General
Here's an interesting bit of info: 200 plastic grocery bags is approximately 1 lb. I average about 6 bags of groceries per week, which works out to 1.5 lb of HDPE per year.by degroof - General
This place seems to have relatively cheap bulk baking products (e.g. 50lb of corn flour for $42.99):by degroof - Polymer Working Group
How about baking soda? It's definitely cheap. In bulk, it's about $2 per kg. Not exactly fibrous, though, and it might do odd things if the resin's acidic.by degroof - Polymer Working Group
So far, I don't think there has been a full set of RepRap parts made by a RepRap machine. I've seen a few parts here and there but nothing that constitutes a full replication. It occurred to me that this would be an important milestone in the project. Sure, there are going to be quite a few Darwins around pretty soon, mostly based on moulded parts, but these are all, technically, first-generatiby degroof - General
I have to confess that I'd probably watch a live webcam feed of a RepRap.by degroof - Reprappers
Could be worse. My CAPA shirt melted in the dryer.by degroof - General
Of course, the philosophy behind RepRap would point towards posting instructions on how to make your own shirts, mugs and mousepads. But that wouldn't raise any money. :-) Off the top of my head... shirts -> inkjet iron-ons mugs -> inkjet decals mousepads -> inkjet fabric + foam rubber sheeting + spray adhesiveby degroof - General
reece.arnott Wrote: ------------------------------------------------------- > now he's > interested enough that I'll be giving him one of > my LiveCDs along with a free computer I'm getting > for him in a couple of months time. I wonder if pre-printed LiveCDs with the RepRap logo on them would be of interest to anyone.by degroof - General
Have you checked pet or livestock supply places? They might have animal feed grade cellulose and psyllium at lower prices. I'm pretty sure psyllium is used as a supplement for horses, so you should be able to get it in large quantities.by degroof - Polymer Working Group
Brian Dolge Wrote: > %90 of the remaining problems could be solved by > including a few routines that check the structural > characteristics of the model. For instance: > "Don't print anything with an edge less than 1mm > wide and an inside angle less than 90 degrees." > "Don't print anything with a bursting strength of > more than 100 psi." Already we've disposed of >by degroof - General
That reminds me: What's the convention for AoI objects? Should a unit be an inch or a millimeter?by degroof - Reprappers
Shouldn't matter. They're probably both 24AWG. I ended up using: - leftover speaker wire for the 12V power lines - twisted pairs pulled from an old VGA cable for the serial lines - the unused wires clipped from the stepper motors for the heater and gear motor Seems to work OK.by degroof - Reprappers
There's some talk about alternate sources here: Seems like, of the off-the-shelf parts, the steppers are the hardest to source.by degroof - United Kingdom RepRap User Group
I wonder how many people will be jumping on those parts when they're ready. I'm (patiently) waiting for these to become available: - RP parts kit for Cartesian - RP parts for extruder - extruder shaft and bearing It might be useful to start a thread to find out how many people are looking for these parts, to get a feel for demand. I suspect that there are quite a few who haven't actually voicedby degroof - Reprappers
VDX Wrote: ------------------------------------------------------- > I think it's easier and cheaper to build a servo > with a radial or linear measure, then the tandem > of stepper and a 'following' DC-motor ... > Probably true. I keep thinking of shaft-encoder motors as expensive. When I first started in the business, printer manufacturers were switching from shaft encoders to stepby degroof - Reprappers
Regarding scaling up the motors... I have this half-thought-out idea of a system that uses cheap stepper motors for positional accuracy and larger DC motors for torque. The larger motor would track the position of the stepper through some sort of feedback mechanism. Sort of a power steering linkage for stepper motors. The first implementation I came up with was to mount a center-off dpdt switchby degroof - Reprappers
The OLPC "Give One Get One" (http://www.laptopgiving.org/en/give-one-get-one.php) program started this week. I wonder if those things are powerful enough to run a RepRap. Looks like it doesn't run Java by default, so it'd be a bit of effort to install everything needed.by degroof - General
I wonder if there's a way to estimate the number of working RepRaps worldwide. I'm guessing there's currently five or six. It'd be interesting to have a counter on the main RepRap site. Maybe have some way to register a RepRap along with its location and incept date. The data could then be used to generate all sorts of graphs and charts.by degroof - General
At this point, I've pretty much decided to wait for the moulded parts to become available. I figure RepRap distribution's still in the long, flat part of the exponential curve. I can be patient and wait for it to pick up a bit.by degroof - Reprappers