The only Reprapper in NJ, so far. I'm working on a Mendel in order to make all the things I design in my mind while trying to fall asleep at night.
- B&TRap- Block and Tackle Repstrap. Currently in design stage. Will go into prototyping once I've completed my mendel. (too much work for the small scale. abandoned)
- OpenX- A minimalist X axis carriage using bearings. A drop-in replacement for the Sells X carriage.
- Prism- An Extruded aluminum Mendel frame.
Testing / Ongoing Experiments
- Replacing steel bearing rods with extruded carbon fiber tubes
- Testing Silica Aerogel as a hot end insulator
- Mendel-parts.com Generation_6_Electronics
- Glass Extruder Nozzle
I'm going to try something new in this space. instead of just a bio, i'm going to use it to document all my various ideas and experiments. Once an idea is fully formed, i'll move the info from here to a dedicated wiki page. my conceptual idea is a chalkboard; here, i can be fast and loose. I don't expect anything below here to make much sense to anyone else, so beware.
Glass Hot end
I've been experimenting with a glass hot end. actually, i have a vested intrest in a glass hot end, as it will be the first hot end i make and print with. my mendel won't print till the idea works. rocket scientist was kind enough to send me a couple samples to play with. he is working on making an all glass nozzle, with drawn glass similar to a pipette. I think that's really clean, but i don't have the glass working experience, or equipment, or space. instead, i'm trying to use a straight glass tube. it's "simple" to cut borosilicate. i've managed to mess it up twice :-)
Regardless, the pieces i cut were still usable, and i'll chalk my complaining down to me being a perfectionist. all you need to do is score the glass, put some moisture on it, and bend it. a crack will progress through the glass originating at the score. simple enough. I used a dremel diamond bit (not in the dremel, just in my hand) to score the break-point. youtube taught me, so if you need to learn, go there.
I like the simplicity of resistor heaters. after all, it's basically a coil of nichrome, already calibrated, in a nice package. I tried using a strip of aluminum i got from home depot. it's about 1 meter x 2cm x 3mm. (my mind is switching over to metric!) I don't have the tools to cut, by hand, anything larger. however, now that it's all done. i don't think it will work like i'd hoped.
it's just my first iteration, though, so i've learned a lot from it. first problem is thermal expansion of the compression fitting. copper and aluminum expand too much, so i have to tighten the bolts so much the glass cracks. this leads to the second problem with my first attempt, which is leaking. there defiantly needs to be a gasket. I'm just hoping it doesn't interfere with the plastic flow.
I don't think these problems are insurmountable, though. I've already posted some ideas for improvements to the basic idea in the forums (i'll put up links later)
Mount for cold end
pulled in from the forum Wade's has a 16mm diameter by 10 mm tall cavity in the bottom, where the filament exits the extruder. I filled this cavity with leftover M8 washers. (I don't know if they are standardized at 16mm OD, but mine were) 
The glass tube is 8mm and fits perfectly in the washers, centered on the filament exit. 
I cut a strip of aluminum to fit on the bottom of the wade's, and drilled holes to match the screw holes. I drilled a 8mm hole to match the, now 8mm, cavity. I did this by using a piece of masking tape as a template; stick the tape to the bottom of the extruder, poke a pen through the tape where the mounting screws go the mark the edges of the cavity, unstick, and match the mounting holes to the holes in the aluminum. I then used a large countersink bit i happen to have to make the M8 hole conical. 
I made another ring to use as a ferrule on this end. 
tightening it too much makes it bow a bit too much, could probably do with one less M8 washer. both the plastic and aluminum bow. 
I currently have the mounting holes on the aluminum tapped for M4 screws. it's a bit annoying when attaching to the carriage, but helps keep everything tight until it is attached to the carriage. And you will need M4x20 screws; 16mm screws are just a bit too short and don't engage the captive nut.
very little heat moves up the tubing, but the aluminum and stack of washers should dissipate the heat that does.