Friday, November 28, 2008
AVR controllers built
I have got my stepper controllers built , now for firmware.
How I got my avr programming kit up and running
Monday, November 24, 2008
120 parts built so far! Which includes a reasonably complete set of 90 printed Darwin parts; everything except the jigs and molds for the toothed belt pulleys, minus a few parts that I didn't use myself (like the foot spacer). I'd suggest spending the $10 on some quality toothed pulleys, as that will save you a lot of hassling with broken pulleys.
The quality is not perfect, but these parts work. My extruder has built most of these parts using several extruded parts built by previous incarnations of itself. You can expect to have to do some work with a needle file on a few of these though, just as I had to with my original cast parts, but overall I think they're quite good. Some of the larger parts have noticeable warping, but nothing too critical.
So, who wants em? I'll let them go for the cost of materials (roughly $30) plus shipping. More importantly though, I'm looking for someone who's relatively local (Toronto, or even Vancouver), and serious about building a RepRap. That way I'll be able to help out with the build, and replace any parts that get broken. There's nothing worse than having a broken part that prevents you from printing out a replacement for said broken part.
Send me a note at wbortz at gmail dot com if you're interested; extra points if you've already got the electronics up and running. :)
Wednesday, November 12, 2008
History Repeats Itself
Smug in the knowledge that I'd outsmarted this particular pitfall, I still managed to get caught by the very problem I thought I'd fixed.
The other night I noticed my Darwin had shut down just after laying down the raft for the X carriage. The error log showed that my temperature sanity check had been triggered, so I went down to the lab to check on things.
At first glance it looked like the PTFE insulator simply failed...
However, once I peeled off the insulation, the thermocouple popped right off the heater, as did most of the JB weld. Oops. So, similar to what happened to Nophead's extruder, my thermocouple came loose, causing my heater to overheat, which in my case caused the heater barrel to melt its way out of the PTFE insulator.
The sanity check did catch it, and prevented any further damage from occurring, but it didn't catch it quite in time to prevent wrecking the PTFE insulator. Which is too bad; I've managed to print over 80 parts so far, and only had 4 more large parts to go (plus a handfull of small bits) for a complete set of printed Darwin parts.
Ah well, back to the drawing board. Next up is fire cement!
Wednesday, November 05, 2008
Recently I've had a number of questions about my build setup, so I thought I'd blog it so the rest of you could see it.
I'm at the point now where my Darwin runs more or less unattended at night. I still don't trust it completely though. It's not that I'm worried its going to take over the lab; I'm worried it's going to break something and make a big mess as it extrudes plastic all over the place.
So, I set up a web cam to keep an eye on it. Pretty obvious, actually. The neat part is though, what with the fancy cellphones available these days, I can keep an eye on my Darwin from anywhere I've got cell access, via the magic of VNC. I can start and stop ReplicatorG from anywhere, and even cycle the Arduino power by rebooting my computer remotely. Even more importantly, it makes a great conversation starter at parties. :) Once I've sorted out the intricacies of gphoto2 and gtkam on Linux, I'll post a link where the rest of you can check it out online.
I'm also a little concerned about the JB weld giving out soon and causing the heater to go overboard while I'm away, so I incorporated Nophead's idea of a thermocouple sanity check in the firmware. If the heater has been on full blast for 10 s and the temperature hasn't increased, I shut everything down and throw an error message. So far so good; it responds nicely to random pulling of thermocouple wires. There's a special case of an intermittent but mostly off failure that it would miss, but I'm not going to worry about that yet.
Finally, I got tired of having to untwist or unkink the filament feed, so borrowing Andy's idea, I bolted a coffee can (I bought the Illy brand specifically because I wanted the nice cans it comes in!) to some plexiglass (it was handy), and hung it from the ceiling with some damaged kite lines (the Cabarete locals are infamous for tangling kites) and a jury rigged swivel (it was handy). Works perfectly – I haven't touched it since I set it up, and no more twisting or kinking.
Now I just have to stop by the lab every once in a while to collect the parts, clean the bed, and start the next batch. Life is good!
Sunday, November 02, 2008
A tale of two rulers
In which your narrator gets mired in the no-man's-land between SI and U.S. customary units...