Optimizing fabrication outcome in low-cost FDM machines. Part 1 - Metrics

Several models of FDM machines, characterized by different architecture and hardware components, have flood-ed the market in the last 5 years. As a result, given the high sensitivity of FDM to the specific machine characteris-tics, the search for optimal printing parameters is a renown problem. This two-parts paper proposes an easy-to-follow and low-cost procedure for the characterization of any given FDM machine. The method allows the evalua-tion of the effects of a wide selection of FDM process parameters on the quality of 3D printed parts. The first part focuses on the definition of a series of metrics to be measured on a series of test prints to evaluate the quality of the produced parts. Specifically, several effects are considered: dimensional accuracy, small details, overhang sur-faces, ability of printing small holes/thin extrusions and overall quality of the prints. The evaluation of seven qual-ity parameters on a single print is made possible thanks to: i) a specifically designed specimen that is made availa-ble to the user and ii) a rigorous and repeatable measurement procedure, which are both discussed in the first part of the paper. The second part presents the characterization procedure, the statistical tools used in the experimenta-tion and provides guidelines to be used for the characterization of any FDM machine. The whole procedure is tested on a desktop FDM machine to demonstrate obtainable results.