MPCNC Gantry-Rack Style Conversion (For large builds)

thingiverse

This is a solution to the large MPCNC gantry flex problem. With a rack-style gantry, you can build the machine as long as you want in the Y direction - within reason, of course. The C-RollerCenters, C-RollerMounts, and C-RollerCaps in my pictures are old revisions. The files here are the most recent, so don't worry if your parts look a little different - they're even better. So, you want to build a huge MPCNC machine? Me too! I wanted to build an MPCNC that could mill standard 4'x8' sheets of wood. Once I built my machine, however, I realized there were a few rigidity issues that needed to be addressed in order to make this machine more effective at this size. Most of these issues were due to the Y-Axis rail flexing heavily under tool pressure when pushing in the X direction, especially near the center of the machine cut area. In 9' it's not unreasonable to have huge amounts of flex. So, with this Rack-Style Gantry, the rail will only be 12" or so - thus curing the problem. Another issue was sag on the support rails. See my thing:1800589 To build this machine, you'll need the following hardware: * 2x C-RollerCorner_GR_CONV * 2x C-RollerCornerM_GR_CONV * 4x Spacer_Corner_GR_CONV * 4x C-RollerCap_GR_CONV * 2x C-RollerCenter_GR_CONV * 2x C-RollerMount_GR_CONV * 2x SpacerCornerC (stock spacer) * 20x additional 608 bearings * 24x 6-32 x 1-1/4" screws * 24x 6-32 Nylock nuts * 2x conduit for new Gantry X-Support rails (cut the same length as your machine's X-Support rails) * 1x conduit 12" for new Gantry Y-Rail * 2x conduit 14" for C-RollerCorner support (length is new gantry Y-Rail + 2") * New timing belt (if not using existing one) To assemble the machine, follow these steps: Step One: Lay the 2x new Gantry X-Support Rails into the RollerCorners. Use SpacerCornerC_GR_CONV for the RollerCorners and Stock SpacerCornerC for the RollerCenters. Step Two: Install RollerMount_GR_CONV onto the RollerCenter pieces and install RollerCap onto each RollerCorner. Only lightly snug the screws. Step Three: Reinstall timing belt on either side of gantry by looping the belt onto itself in the cutout on the flat side of the C-RollerCorners. Step Four: Rewire your MPCNC and enjoy! I thought of this design while in the shower back in December... I've been busy, but I finally managed to finish it up! So, I hope this helps anyone who built or is building a large MPCNC! Post any questions or comments and I'll respond to them as fast as possible. Also, thank you Vicious1 for your excellent MPCNC project! I couldn't find any STEP files or Inventor/Solidworks files for the original MPCNC STL files... so I hope you don't mind my hacky reverse-engineering. Print Settings: * Printer: Prusa i3/Hictop 3DP-11 * Rafts: No * Supports: No * Resolution: 0.25 * Infill: 55 (I would recommend 55%, but I've printed all of mine at 33% while designing and testing this project and I have not had any issues yet)