I noticed the outside surface of the mini-mug is pebbly. Little blobs all over the surface. Is this a 'catch' in the turning of the extruder screw? Maybe a pause between line segments? What software/toolchain/firmware are you using? I envy you your notable success! Hopefully I'll be joining you in a month or two...by jgilmore - Mechanics
Except that the extruder gets moved over to the darwin. It's the most complicated bit to build, and requires the most variety in materials. I was planning on moving the extruder, steppers, and electronics over to the darwin once I have all the pieces printed out.by jgilmore - Reprappers
So what you're saying here, nophead, is that if we want induction heating we probably need to make the barrel out of something ferrous and/or very high electrical resistance to make it even remotely practical? That's doable, the only reason the barrel is brass to begin with is the high heat conductance combined with easy machinability. So we add ferrous and/or high resistance to the requirementsby jgilmore - Mechanics
The FTIStrap Doesn't need to produce ALL the parts for a darwin to be EXTREMELY usful as a repstrap. If the hot-glue is an issue for most of the parts, that's still OK. As long as it can print out the parts for an extruder, and they work well enough when made out of hot glue. Then you mount your new darwin MK II extruder on your FTIStrap frame, and print out the rest of your darwin... I'm of theby jgilmore - Reprappers
No, it is NOT wrong to give up on the java package and write your own software. In fact, this has already been done. Search for Enrique's fine "skienforge" software. Written in python, it does almost everything the host software does. More in several cases. And all without the JVM headaches. Are you using the Arduino? If so, it's (almost) plug and play - you can use my send.py as both a "jog" inby jgilmore - RepRap Host
Not really. The project is being funded by the US Navy again, so it's under a bit of a publishing ban. Last I'd heard they'd confirmed Bussard's results, and where planning on building a larger (still scaled down and still pulse operated) model to confirm more of the math. But IIRC, that was news back in March or April.by jgilmore - Reprappers
Skienforge Contains (in a subdirectory) an executable for each of the M-codes. It's intended for people using seperate software (MACH3, I think. Open-source CAM software. It doesn't generate g-code, it's just "machine interface via parrallel port" software) which will execute the external program each time it comes across an unfamiliar M-code. People doing this (I think nophead is one) use an ardby jgilmore - RepRap Host
I've looked at all sorts of conversions. I'm thinking that for people that live in coal country, small-scale coal liquification to make kerosene (parrafin) for a diesel engine may just be the way to go. The setup would cost, but it'd be MUCH cheaper than an equivelent-wattage solar or wind electric setup. And if push comes to shove, diesel is a trade good as well. Problem with electric is that wby jgilmore - Reprappers
I didn't measure. One's about two inches, the other two and a half. Shorter than the drill bit, long enough to wrap some heater wire around.by jgilmore - Plastic Extruder Working Group
For months I've been dreading trying to make the extruder barrel. I shopped around a bit, and the local machine shops all charge a minimum of $75/hour 1 hour minimum for that kind of work. So I ordered my micro drill bits, found a friend who had a lathe and a drill press, and started to make plans. It turned out to be MUCH easier than I thought, and I didn't need a lathe, a drill press, or anythby jgilmore - Plastic Extruder Working Group
Thank you pjr. I don't have an extruder so I haven't run into that problem. Several days after finishing with send.py, I'd noticed in my hacking away at the g-code firmware that the tempurature code did repeatedly print the temperature, but hadn't come up with a solution yet. I'll definately be using this. Eventually, I mean.by jgilmore - RepRap Host
I like the idea of teflon tape. I wonder if you could use teflon plumber's tape? I have some of that! It's not sticky though. So I guess the question becomes "is the friction low enough that I can tape the teflon tape at either end (folding it around the top of the stage) instead?" I'll have to add that to my list of things to try.by jgilmore - Mechanics
I was going to try zip ties too, but realized before I put it on that the bulge wouldn't fit. I twisted a bit of bailing wire around it and then clipped of the twisted bit. Hasn't come off yet, and it's plenty small enough. If I was posting from home I could even post a picture of it. I don't know what sort of wire it really is, I got a small coil of it from the trunk of a car a I bought from thby jgilmore - Reprappers
I've been trying to generalize the midpoint circle algorythm to all eight octants. I figured out how to start a python interpreter here at work, so that's what I've been doing between using to test the modified algorithm. I've got something that works, but it's ugly. The "advance to next octant" conditional is different for each octant. The "error +=" statments comes either before or after eachby jgilmore - RepRap Host
I began to suspect my the gearmotor was substatially beefier than the recommended solorbotics one when I measured its resistance and calculated the power requirements. That was mostly confirmed when I saw somebody selling new ones for $150. Still, if I set the PWM for 25% or so as a maximum I think it'll be fine. Unless the PWM pinout goes high when the arduino is reset, in which case I'd have tby jgilmore - Controllers
OK, fine. Whatever. I'll do it myself. The board (DC Motor Driver) is pretty much fine as is. Replace the 560 Ohm resistor with 1K ohm so you don't blow the LED, and you're pretty much good to go. The "100 uF electrolytic capacitor" is only rated to 25v, so the margin on that one is a little thin, but I think it'll be OK. The real problem isn't with running it at 24V, the real problem didn't stby jgilmore - Controllers
Isolation milling? Here I though the plan was for the reprap to embed all the components in plastic, and then wire them together with molten solder? That way we don't need a milling head (few heads overall) and we a lesser variety of build materials. It'd be nice to need only solder, plastic, and IC's. The question would be if the needed acuraccy is achievable - laying down a bit of plastic toby jgilmore - Controllers
OK, I suppose I have some time too. I see people selling FRP rebar, why don't I see people selling just the FR part? As in fiberglass cord/cable for embeding in concrete? I have seen concrete board, which is essentially a fiberglass net folded in half and with concrete poured in in, but apparently you can't but just the net? Maybe the fiberglass & resin people is where I should be looking.by jgilmore - Plastic Extruder Working Group
Yes, possibly. I have a theory that the min switches are MUCH more likely to cause a crash if they're broken. I had that happen just this last monday - went to demo it for a dinner guest and it did fine till about halfway through writing "hello world!" and then crashed. A wire had come loose. I'm going to wire them all up in reverse as soon as I get a chance so that "switch open" (or wire loose)by jgilmore - Controllers
Which endstop did it break against? X Max or X Min?by jgilmore - Controllers
Quote you'll never find enamel on such reinforcement bars. NOT EVER. etc, etc, etc. "epoxy coated rebar" gets 136K hits. and is the offical ASTM standards for epoxy-coated rebar. It's widely used. OK, so it's epoxy and not "enamel" - same diff, isn't it? The outside of the rebar is bumpy, and that's sufficient. Any lost chemical bonding is more than offset by increased corrosion resisby jgilmore - Plastic Extruder Working Group
I don't care if it sticks, though it would help. It's bound into a channel mechanically. It's a loop and can't be "pulled out". The texture on the outside of re-bar is for the same thing. There's a formal name for the little bumps, but I forget what it is. The welded wire is welded at all joints for the same reason - the wire is smooth, but it's bound at the joints and can't move even if it was zby jgilmore - Plastic Extruder Working Group
The heater barrel is built as normal, threads on the top, a small hole in the bottom, and nichrom wire and a thermistor between. The insulator is the differance. And that's made of reinforced mud in the following fashion: First, get a nut that will fit the top of the extruder barrel. Solder the wire onto this (or not, doesn't make much difference, but it makes holding things in place later easiby jgilmore - Plastic Extruder Working Group
You could use the skeinforge toolchain - that doesn't require any graphics at all... You can slice, Dice, and configure from the command line. OK, there is a graphical configuration interface, but you're not required to use it. Note that the skeinforge toolchain is gcode, not SNAP, so you'd have to use the gcode firmware. I don't know of a host-side gcode-to-SNAP converter, but one would be fairlby jgilmore - RepRap Host
I've looked over the website for truespace. It's a very mature program. With lots of features. But of the highlighted features, only 1/16th had anything to do with CAD as opposed to animation and art. And that was only snap-to-grid. So it, like blender, is primarily an animation package. And it's free as in beer, but not free as in freedom, and it's windows only. I don't see it's advantage oveby jgilmore - RepRap Host
I read about the concrete extruder awhile back, and haven't really heard anything about it lately. Seems like it'd be a good idea, strong, cheap, and readily available. I've seen comments that say it doesn't work, but nothing to say why. I also haven't seen an official "Eureka! Use this instead of slippery, expanding, expensive, and unreliable PTFE!" So, in the absense of any hard experimental dby jgilmore - Plastic Extruder Working Group
Quote The host software is largely platform independant, no? Well, yes. But I'm a bit predjudiced against mswindows too. I guess it's not prejudice really, as I worked technical support for Gateway for six months, and have repaired computers for other people for years. I got tired of constantly dealing... wait a minute. Drat! Nevermind, we're talking about reprap here. C, python, perl, lua, evenby jgilmore - Reprappers
I'm planning on converting the PWM driver to 24V. I know an EE I can pester! He told me that it should be a matter of replacing four resistors (labeled R7, R6, R4 and R5 in the schematic with 1.2K ohm instead of 560 ohm, and making sure that C1 (100nF) and C2 (100uF) are rated for 30V. Sounds reasonable to me, but shouldn't T1, T2 and T3 (all of them TIP120's) be rated for 24V too? The data sheby jgilmore - Controllers
I have a phone job with limited internet access. So I have time at work to do a little writing about my experiences so far with reprap. First off, I don't like Java, and I don't like windows. I'll use windows and even fix it, clean up after viruses etc but only if you're paying me. I'll use java apps generally only if there is no other suitable app. And sometimes I'll even rewrite it in a real lby jgilmore - Reprappers
How about this: Three heads - plastic, solder, and pick'n'place, and a pot of molten solder with a layer of flux on the surface off to one side. One of the problems with placing the components in the channels before solder is poured is flux. This could be solved by pre-tinning the components. pick them up with a vaccum + hypodermic needle based pickup head, dip them into the flux and down intoby jgilmore - Plastic Extruder Working Group