3D filament shrinkage calibration test

thingiverse

This 3D printer filament shrinkage calibration object draws inspiration from Clough42's technique showcased in his video: https://www.youtube.com/watch?v=0dFThbwAx2Y. To utilize this object, four millimeter metal dowel pins are required - I sourced mine from McMaster at https://www.mcmaster.com/93600A474. Each end of the design features holes ranging from 4.2mm (left) to 4.5mm (right), where the pins are inserted into the tightest corresponding holes, and calipers measure the inside and outside distance between the pins. Raised rectangles facilitate keeping the calipers parallel to the pins. By averaging these two measurements, you can determine the distance between the centers of the holes, which should be approximately 125mm. To calculate the percent compensation value, divide 12500 by this average. For instance, with one brand of PLA, I obtained dimensions of 120.22 and 128.64mm, averaging to 124.43mm. Dividing 12500 by 124.43 yields a result of 100.46%. Therefore, to compensate for shrinkage, you should uniformly scale the model by 100.46% using this particular plastic. I found Clough42's technique particularly clever because measuring the distance between two inner features naturally accounts for under or over extrusion of the outer perimeter, unlike simply printing a cube and measuring its outside dimension.