Sunday, August 24, 2008
Cheers! Another RepRap comes online!
I've had my Darwin close to finished for over a month now, but various software problems have kept me from being able to print until now. I was never able to get the Java host software to work reliably, and due to a slightly off center extruder screw, I decided to try and incorporate Zach's magnetic encoder board. That worked beautifully, but code space limitations meant I had to run the Gcode variant of the firmware (thanks again to Zach!), which required installing and understanding an entire new tool chain, which again took a fair amount of time. It's all good now though!
I had a good laugh on my first minimug attempt though. With great apprehension, I watched the mug take shape, but after the raft was built, the mug looked decidedly triangular, not circular. I almost stopped the print, thinking some joker had switched out the files on the Wiki, when I realized that the minimug.stl file needs to be rotated 90deg about the x axis, otherwise it prints on it's side. Printing a mug on its side definitely does not fit the "no overhangs greater than 45 deg" rule, but it sorta worked anyway. Check it out:
Both mugs are a bit lumpy yet, as my Darwin is a bit loose in most directions - all of my cast bearing inserts are 1 to 2 mm too large, making all the tolerances very loose. Soon I'll print out some new bearing inserts and drill them as close to 8mm as I can, that should sharpen things up a bit.
Finally, a fuzzy cell phone shot - I'm now cranking out RepRap Power Rings, I figure they'll make nice playa gifts next week at Black Rock Desert, a little harbinger of what's to come. :)
You can get a good bearing by filling gaps with soft Polymorph (Jaycar stock it). Just make sure the excess engages over both edges of the hole so it doesn't slip out or move. Oh yeah, don't let it wrap completely around the rod 'cos it shrinks eversoslightly when it cools and goes kinda tight.
Next step is, of course, getting it to build another one :)
They cut plastic real easy and do a great job with slide bearing inserts.
I turned mine (PTFE Rod) on a drill press and finished the bore with a reamer, great results, no play at all.
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