Lulzbot TAZ retractable Z-probe auto bed level compensation with G29 Mod

thingiverse

This modification eliminates the need for manual leveling of the build platform, designed specifically for advanced users requiring firmware and hardware adjustments that may affect the machine's warranty. It also reduces the X-axis printable area by approximately 8mm at maximum X position. Videos of the prototype are available for demonstration. Inspired by MatterHackers' automatic printer calibration update, this modification features a Z-probe consisting of a parallel micro-switch wiring to the existing Z minimum switch and attached to a cam-operated toggle. The probe deploys when the X-carriage reaches maximum X position and retracts at X0 position, enabling automatic bed probing before each print. Note that this modification is optimized for TAZs with the author's stiffened X motor and bearing mounts, though it can work with standard TAZ parts but may require a custom 8mm spacer on the lower X smooth rod due to probe activation. Additionally, removing Z-backlash is recommended by following the instructions in another modification. The required firmware for the Z-probe can be found at this link, and Lulzbot TAZ-specific configuration files are coming soon. G-code for probe deployment and bed probing will also be available shortly. Before installation, it is crucial to perform the anti-Z backlash modification and install the stiffened X mounts (optional without custom 8mm spacers). Required accessories include M3 washers, a 16mm bolt, 12mm bolts, M3 insert nuts with an inserting tool, a 3mm drill or reamer, roller-tipped micro switches, ABS parts without support material, and specific LM10UU ball bearings for the best results. To assemble, print all required parts in ABS, trim and file bearing holder and activator for smooth movement, insert two insert nuts in toggle and one in the bearing holder, drill or ream micro switch holes (if needed), install micro switch with 12mm screws, add bearing in bearing holder, temporarily install activator and toggle, test toggle operation, adjust if necessary, remove components, mount bearing block on X-carriage using original screws, slide in activator, attach toggle, wire up the micro-switch, replace firmware, calibrate probe with assistance from this link, add G-code for bed probing before each print, and finally remove four springs from the bed corner mounts.