3D Printer Tolerance Vernier revision 3

thingiverse

Revision 1.5 released July 1st 2018. For daily updates on status, scroll down to the Status section below. This tool assesses the dimensional accuracy of printed models with precision. It measures tolerance range from negative 0.12 mm to positive 0.37 mm, with micron-level resolution achieved. Note that I emphasize "resolution," not "accuracy." Absolute accuracy and linearity jitters depend on factors like cleanliness of print, post-print sanding, dust on the tool, build bed shifts during printing, and dimensional stability or warping of the material. Printers are often unfairly blamed for prints being half a millimeter bigger than intended. In reality, it's usually the slicer program that makes models slightly larger in X and Y dimensions to prevent features from disappearing due to nozzle diameter limitations. Simplify 3D offers a parameter to compensate for this, but users must measure printing tolerance and input the correct value. When using this compensation feature, the slicer code shrinks the model internally by the specified amount (in X and Y) before generating gcode. Keep in mind that features smaller than the nozzle diameter will vanish from the print. For most models, high accuracy is not necessary, but for mechanical pieces requiring exact fitment, measuring printing tolerance and adjusting compensation is crucial. This tool provides a finer measurement than typical printable tolerance test models, reaching down to microns with only 2 parts required. In contrast, many existing tolerance test models consist of multiple pegs and/or holes on a large base. I envisioned a simpler approach: a conical or piramidal long peg paired with a sliding "hole" piece featuring markings along the peg for reading tolerance. Upon further consideration, adding vernier-type markings to the sliding piece allowed me to achieve an extra decimal place of precision, resulting in micron-level resolution. Scroll down to see a measurement reading example.