Prusa i3 Mk3+ Rebuild

thingiverse

We all love Prusa's, I personally own several of them. However, 8 inches of build height is rather restrictive, so I redesigned a few things about the Mk3 to take full advantage of the 12" lead screws provided in the original Mk2/3 kit. The main part of this build is a new 25 series frame (1" extrusions would be just as good) for the printer. I bought mine cut to size from 8020.net, it cost about $70. For the 2525 extrusions you need 2x 332mm extrusions and 2x 370mm extrusions. For 2550 extrusions you need 1x 332mm extrusion and 2x 480mm extrusions for the Z if using the stock motors. If upgrading to longer lead screws, simply increase the length of the Z extrusions and Z linear rods to match. You'll need ~80 of these t-nuts, be sure to select M5 for the thread and also get ~100 10mm M5 screws https://www.tnutz.com/product/drop-in-t-nut-wspring-ball/ . Also buy 4 of these https://www.tnutz.com/product/anodized-aluminum-4-hole-inside-corner-bracket/ . The only other required part is longer Z rods, everything else you need is included in a Mk2/3 kit. I managed to get 280mm of print height out of the stock motors, and am using 16" z rods. When assembling the new frame, flip the X axis upside-down and backwards so the POM nuts are at the bottom inside of the arm instead of the top, meaning they gain access to 3 inches more lead screw in travel. Then simply flip your extruder to match and enjoy your extra build height. EDIT: 4-7-18 All parts have been finished and uploaded other then the electronics and LCD enclosures, which I'm still tweaking. I've mostly cleaned up the wiring on my machine and posted new pictures of the build. EDIT: 4-20-18 This build is complete and all parts have been uploaded. New pictures have been posted of the final build. There's a door on the electronics enclosure for easy access to attach a Pi Zero W for octoprint, although I ended up deciding to run my machines manually so I didn't design a camera mount. I've also uploaded extra parts for conversions from Mk2(s) to hold a mofset and second power supply. The pictured blue prusa is a Mk2.8, using all the MK3 electronics with a Mk42 bed and Pinda 1 prob. It uses the original Mk2 power supply for the bed and an additional 24v Meanwell power supply for the Einsy board. I'm using an external mofset to run the bed. The Z motors have 365mm threaded shafts, giving me 330mm of total build height. Takes the same gcode as a standard Mk3.