Piper 2 Bearing-less Short Gantries (PTFE Sliders) - 8mm, 10mm, and 12mm rods versions

thingiverse

This is a bearing-less version of the Piper 2's gantries, utilizing common 2 or 3mm OD PTFE tubes as sliders. The problem with steel linear rods is their heaviness, and using other kinds of rods results in linear bearings that chew soft metals/composites like gum. This design concept reduces required parts to build the printer and allows light guiding rods (aluminum, carbon fiber, etc.) for high printing speeds and reduced vibration artifacts (ringing). It also improves rod and screw clearances and achieves complete silence. My first attempt integrated tubes into the gantry but failed because different printers behave differently. Therefore, I separated bushings from the gantry to be individually printed/calibrated/replaced without reprinting the whole part again. As these bushings are a separate part from the gantry, they can be generated via the included OpenSCAD file and used with any (<4mm) PTFE tubing for any rod diameter (up to 14mm with 2mm OD PTFE but too close to screw holes in Y gantry). I also included adapters to use 8mm and 12mm rods with 12mm versions of the gantries if mixing & matching different rod sizes is desired. The only part required are small pieces of PTFE tubing (15 mm long each). Insert the tubing into openings, assemble the gantries, and ensure a snug fit but allow for smooth sliding motion. If grip is too tight, use the included OpenSCAD file to increase tolerance a little bit (e.g., use 3.2mm instead of 3mm). I strongly recommend printing one bushing first and checking how it fits before printing the rest. You can also use the included OpenSCAD file to create bearings for stock gantries (or anything else) but be careful with distances - you cannot use 3-4mm OD tubing for a 15mm LM8UU-size bearing! Regarding reliability, PTFE tubing will likely outlive the user and printer. I'm using it on high-speed machinery that is much faster than any printer and never had one fail in my life. I also use similar solutions along with aluminum rods on most of my printers to reliably print at high speeds. The X and Y gantry versions uploaded are a bit shorter, increasing travel by about 40mm across the X axis and 18mm across the Y axis (compared to the 12mm version). My version of the X gantry is smaller and more complicated but not superior to the default one. I redesigned it for my filament intake Y splitter to fit. I uploaded all parts based on the 12mm original version, so they require GT2 10mm belts/pulleys/idlers. I also uploaded a BL Touch adapter that simply requires a longer X gantry screw and is secured with two extra nuts behind/beside the hotend. Its height can be adjusted via the mounting nuts. Edit: I added a Y-Slider version with 5mm holes for idlers/gears because 10mm tall parts with 3mm bore are notoriously hard to find. You will need M5×25mm screws for these; the holes do not go all the way through the part, and they are meant to tap directly onto the plastic (or they would be getting uncomfortably close to the rod).