Bed XY Skew Measurement Strips

thingiverse

UPDATED 2016nov12: Fixed bugs in Customizer (previously didn't work - check history below for other updates) Uploaded STL files for various bed sizes and 1.75mm filament, plus a pair for Ultimaker 2.85mm printers. You can use whichever fits on your bed, but you'll get the best accuracy by using Customizer to generate strips specifically for your bed size and minimal skew range. This OpenSCAD script generates calibration strips that allow you to determine level of skew in XY axes for 3D printers with Cartesian gantry systems down to approx +/- 0.05 mm without any other measurement devices. I've uploaded calibration strips for an Original Prusa i3 MK2 (250x210mm bed) and Printrbot Simple Metal (152x152mm bed). You can use whichever strips will fit on your printer to see if your bed is square, but ideally you can use Customizer to generate a set of custom strips specifically for your printer based on your filament diameter, nozzle width, and bed size. Once you've printed out the strips, insert a segment of filament into one end and align them back to back. Then read the resulting skew on the vernier scale at the other end (the bisector strip is standard 1mm scale, while the orthogonal strip uses a 0.9mm vernier scale with only +/- 10 measures). If center marks are aligned, your XY axes are square within the resolution of your extrusion width. If they're off, adjust, wash, rinse, and repeat. Released to support ongoing XY calibration discussion at: https://github.com/MarlinFirmware/Marlin/issues/5116 Thanks to Edward Patel for suggesting using printed vernier scales to directly read relative lengths of skew without external measuring devices. Enjoy! -=dave // history: // -0.9.1 - 2016nov12 - fiveangle@gmail.com - Fixed Customizer bugs: // - apparently Customizer doesn't work with Boolean value/comment pairs // - fixed filamentDiameter Customizer value/comment pairs transposed // - Changed maximumSkew math to account for +1 value of vernier // - Reduced maximum skew from 11mm to 6mm (if your bed is more than that, you've got problems) // - Fixed 3mm filament diameter to the true value of 2.85mm (I've never owned a printer with this setting myself) // -0.9.0 - 2016nov05 - fiveangle@gmail.com - Released on thingiverse to facilitate ongoing XY calibration discussion at https://github.com/MarlinFirmware/Marlin/issues/5116 Print Settings: Rafts: No Supports: No Infill: 100% Notes: Perform all other normal calibrations first (summary here: https://www.3dhubs.com/talk/thread/howto-calibrate-tune-and-fine-tune-your-printer-and-filament) Print with one shell Print in PLA for best results on FDM printers Print at the lowest temperature possible If printing on a heated bed, wait for it to cool down close to room temperature before removing the print Use a filament color with good reflectivity for easiest reading of vernier scale (silver, for example)