After some consideration I decided to go with a Prusa i3 as my second printer. The design is relatively simple, and should be right in my $500 price range. I'll post a BOM once it's finished, and document my build process.
For the last few months I've been taking a break from 3d printing. I've started printing again recently, but I've also been trying to decide if I want to build another printer. I currently have a ramps 1.4 setup, 5 Pololu drivers, some high strength 8mm precision smooth rod, and a 8x8 heated build plate along with some belt and pulleys. My final two are the Rostock, a very cool "cheap" to build delta printer, and the Prusa i3, a very common reprap build. Over the next week I'm hoping to price out the builds for both, and decide what I really want to build.
After talking to a few community members, most notably Jetguy, I have decided to put my extruder building on hold, and go with some more simple modifications
I've been printing very little lately, I've found that ABS prints have been curling more than normal lately, and that PLA prints have just been failing all together. I assume this is due to the extra heat and humidity in my office, but I have a plan to fix this. I'm going to try out the idea here: http://www.mastersketchup.com/qubd-extruder-jam-fix/ along with some tips from Jetguy over on the makerbot vintage group. I plan to create a barrel as Matt Donley describes, but a bit longer than the standard size. In the gap that'll exist between the hot end and the cold end I plan on lining the thermal barrel with heat sinks. I'm hoping these two modifications will be enough to allow me to print in PLA reliably. First I need to figure out if I want to try to tap a steel tube or if I want to drill out a bolt.
I've been playing with some nRF24L01+ as of late. I've got two hooked up my Arduinos and have been trying to get data transmission working between them. I fear that since I got them so cheaply they might be flawed, or that Wifi has been interfering with them. More testing will hopefully shed some light on this.
My printer has been pumping out some good quality prints in both ABS and PLA for the last week or two. I've upgraded to linear bearings and a ball bearing follower on my x axis, a mk8 nozzle, and rigged a fan to blow on my extruder stepper, and my filament gap. With this setup I've been printing both high quality ABS prints, and even gotten off a few hour or longer prints in PLA. I was having some heating issues on Sunday night were the temperature seemed a bit low during a print, soon into a PLA print my safety cutoff board's light went out and it caused the heater to turn off. Upon restarting my machine the light comes on and all connections on the board are secure. As soon as I try to heat up the head(as soon as voltage is sent to the board) the green light goes out, given this I assume it's not a loose cable on the main boards end, but rather a blown component. I suspect the relay, the big 2w resistor, or the power rectifier are either shorted or blown, so I've ordered replacements for all of them. This will end up leading to more general maintenance on my bot: installing linear bearings to replace bushings, greasing the rods, checking all the screws to make sure they are tight ,and re-wrapping the extruder.
I spent about an hour and 1/2 working on calibration on the Thing-O-Matic last night. My prints are coming out very oozy on top. The fan on the extruder also isn't running, so I need to open up the bot tonight and check out the connection.
Last night I did some calibration on the Thing-O-Matic, I was able to print faster than I've ever printed before, and was able to get some petty good detail. I find that my printer leaves flat areas a bit rougher than I'd like, but then again it might be the plastic. For some reason I find that the Tardis blue ABS that I've been using seems to come out a bit gooey from the extruder. I think I'll re-run my gear test prints using a bit lower of a temperature and see what I get.
Last night I upgraded my Thing-O-Matic to use Jetty's Sailfish firmware, along with upgrading the extruder firmware. The extruder was a bit harder to upgrade since it required getting a USB cable in at a very odd angle and detaching the connection to the main board, and the power connection to the PSU. The main board upgrade to sailfish was easy as could be to do. I'll be running calibration tonight so I'm hoping to get some good speed and quality.
Just a note, the package name for node.js is nodejs not node. I spent a good 20 minutes on Saturday trying to figure out why my node.js hello world would not run on the pi.