Anti-Wobble Anti-Backlash Auto Bed Probe for Prusa i3 (Cheapest)

thingiverse

Outdated-Discontinued Update1 4/4/2016 : Using two endstops connected in series at either side of the x-axis will significantly improve leveling repeatability. Just flip the part and print for the X-idler side. Changing probe grid points to 2, which means placing 4 points at the most rigid areas on the bed above linear bearings, makes z offset measurement much more consistent. This part is the cheapest and most effective improvement implemented on my homemade Prusa i3. I designed this thing because of a need for Auto Bed Probing, by remixing the design done by jamesarm97 -Thanks to him- and adding a holder for the micro switch from an old computer mouse. Surprisingly, The print quality and machine reliability improved significantly in several ways: 1.ANTI_WOBBLE : Better layer alignment by eliminating tension between X-Z axes and preventing bent Z screws from making X axis wobble. 2.ANTI_BACKLASH : Basically preventing backlash by using two nuts and a spring separating them. 3.AUTO_BED_PROBE : Compensating for unlevel build platform by Auto Bed Probing and setting z offset matrix which leads to perfect first layer adhesion and perfect finish on faces printed directly on glass (PLA). 4.Replacing the unfriendly Z end stop which required constant adjustment. Changes in Configuration.h in Marlin Based Machines : 1- Inverting your z min end-stop setting by changing false to true. Normally, z end stop is closed when z axis homes. We want it to be open when z axis homes. const bool Z_MIN_ENDSTOP_INVERTING = true; 2- Activating auto bed leveling by deleting double quotes from define ENABLE_AUTO_BED_LEVELING 3- Update these settings for the probing grid: define LEFT_PROBE_BED_POSITION 50 define RIGHT_PROBE_BED_POSITION 150 define BACK_PROBE_BED_POSITION 150 define FRONT_PROBE_BED_POSITION 50 3- Set the number of grid points per dimension. I wouldn't see a reason to go above 2 (=4 probing points on the bed) define AUTO_BED_LEVELING_GRID_POINTS 2 4- Set the probe offsets: These are the offsets to the probe relative to the extruder tip (Hotend - Probe). As we directly use the hot end nozzle to probe bed, offset of x and y will be zero. Setting z offset needs trial and error, set to zero in the first upload and re-set it by using a sheet of paper as the gauge and reading this value on LCD as the hot end touches the sheet. My measurements led to 1 mm offset which would be different depending on build platform rigidity. define X_PROBE_OFFSET_FROM_EXTRUDER 0 define Y_PROBE_OFFSET_FROM_EXTRUDER 0 define Z_PROBE_OFFSET_FROM_EXTRUDER 1 Start G-code for the slicing software: M104 S G28 X Y G1 X100 Y100 G28 Z G29 G1 Z0 M109 S Print Settings Printer Brand: RepRap Printer: Home made Prusa i3 Rafts: Doesn't Matter Supports: No Resolution: 0.23 mm Infill: 30%