Parametric Negative Test

thingiverse

This test will measure the ability of your printer to leave small spaces in prints. This is fundamental when printing objects with internal mechanical parts, such as hinges, bolts, clocks, kaleidocycles, etc.. To achieve such precision, it is advisable to calibrate your printer. I followed the instructions in https://teachingtechyt.github.io/calibration.html . In particular I recommend "XYZ calibration" then "Extruder E-steps Calibration" and "Slicer Flow Calibration"; in this order. One hint : the above page uses gcodes to set printing parameters; but the interface of your printer may have menus to set those values more conveniently. There are some tests to measure how well your printer is calibrated, but they take a long time to print. The goal of this test is to be fast to print and yet informative. It will print small block with slits of width from 0.05 to 0.50, in steps if 0.05. Since the first layer may be printed too flat (so called "elephant foot") the slits are chamfered, so that this should not affect the purpose of the test. Moreover this test is designed in OpenScad, so you may change the number of slits and their width, the size of the box, and the size of the chamfers. Currently it is optimized for a 0.2 head and 0.2 layer height. Note: you will need a recent version of OpenScad. It will print in around 20minutes, so if it did not work out, you may change parameters and try again in short time. There is no need to enable supports, nor rafts; and you should set infill to zero. You will need a Feeler gauge, so as to check if the slits have the desired width; as you see in the picture.