Prusa Update

It’s been a busy start to the summer! I was able to go to Maker Faire, and now that I’m back I’ve spent every spare second on my bike or at the new hackerspace in town. One benefit of being a hackerspace member is that I finally have a place to keep my big /noisy / messy projects!

Here’s a pic of where it stands right now. I have everything together, but it’s not wired up yet. I’m also replacing the clonedel parts as fast as I can. They are causing more trouble than they are worth right now.
Here’s a link to solid state depot’s wiki on my prusa.

Here’s a pic of my monster e-stop button. It came out of a printing press. It is wildly overkill, but it looks cool. It is currently wired up to the psu, so if the switch is tripped, it cuts power to the machine. dead stop.

I’ll update more when I do more. I’ve been learning how to use a lathe in order to drill out some hot ends. It’s been exciting so far…

completely unsorted reflections on building a clonedel

1) Last weekend I completed drilling out my clondel kit and started bolting things together. Here’s a list of things I realized.

2) Having precisely cut threaded rods is nice, but not necessary provided they are longer than spec.

3) Drilling out the metrix createspace clonedel kit is difficult verging on impossible to do exactly. The vertex pieces that require precision don’t have flat, 90 degree sides. Also, some of my pieces varied +- 3mm in thickness. That is a big problem when the piece is 15mm thick, and it’s off in the – direction. I had to do a fair bit of eyeballing on those undersized pieces or else the drill bit would have just ripped through one side. This kit is a lot better than nothing, but the first thing to print is definitely replacement pieces. I also think I have one of their earlier versions judging by the way my z motor brackets look, so potentially they have improved since the first few batches.

4) I scavenged some 8mm rod from two desktop printers. That gave me enough for the z and the y axis. To get the long rods needed for the x axis I think I will probably need 2 more printers to destroy. I’ve been toying with looking into the rods from ikea filing cabinets to see if they are even vaguely straight or consistent. I doubt it.

5) Looking at the printers made me wonder if dc motors could be used with opto-encoders for this project as a replacement for the steppers. I’m not sure what would be the best way to do it, but I’m considering making a “stepper driver board” out of an arduino to see if I can get it to behave as a drop in replacement.

6) It appears like the thin and thick sheet are unnecessary for a prusa. Well that’s nice.

7) I’m looking into using my xylotex 3 axis kit as the stepper interface for this prusa. I think that just means I need to put the mosfets, end stop pins, and thermistor circuits on a shield for my mega and I ought to be good to go.

Nema 17 on the left, Nema 23 (with 260 oz/in of torque) on the right
8) I’ve got 3 nema 23 260 oz/in steppers that would be delightfully overkill for this. I’m wondering if it is worth the trouble of building new brackets for everything. I know that torque does not necessarily equal speed, but I would like to see how fast those would print. I would try the extruder (possibly) and the x and y with those monsters. The z axis doesn’t need that kind of speed.

9) I ended up buying some 8mm linear ball bearings from ebay. 12 for $15 isn’t too bad considering they will last a lot longer than the pla.

10) Using the testing setup of repg from Ben Jackson I have been able to connect to a mega 1280 and a 328. I can’t do much else before it crashes, but at least its a start. Repsnapper seems to work flawlessly with the 1280, untested on the 328.