Quality In Every Layer: Assessing Dimensional Accuracy of Distributed 3D Printing for QA Phantoms
Abstract
Purpose
To assess the feasibility of distributing the workload of manufacturing 3-dimensional (3D) printed Winston-Lutz (W-L) phantoms for donation purposes across multiple locations and a variety of printers
Methods
To ensure ethical donation practices and maintain the quality of donated equipment, two test artifacts (TAs) were designed to assess the dimensional accuracy (DA) of various 3D printers before producing W-L phantoms. The W-L phantoms are composed of two interlocking cube halves, housing a central spherical cavity designed to securely hold a 6.35 mm stainless-steel ball-bearing (bb). The first TA focused on accuracy of the spherical cavity and consisted of two blocks with arrays of five semi-spherical recesses (SSRs) of planned diameters (6.5, 6.6, 6.7, 6.8, and 6.9 mm) on one surface. Planned diameters were larger than the bb to account for an estimated cumulative (in all directions) DA of 0.35 mm. The second TA assessed DA of alignment pins and holes and consisted of a block with an array of five alignment holes (1.8–2.2 mm diameters) on one surface and a block with a 2 mm diameter pin on one surface. The fit between the pin and holes was used to evaluate DA.
Results
TAs were printed using PET-G filament on five different manufacturer or model printers across four United States locations. Best fit SSRs ranged from 6.5 to 6.8 mm (median and mode = 6.6 mm). Best fit locking hole sizes ranged from 2.1 to 2.2 mm (median and mode = 2.1 mm).
Conclusion
The results indicate that the mean DA of the printers was 0.25 mm for SSRs and 0.1 mm for alignment holes. The offsets determined from the TAs will be used to customize digital designs for each printer, ensuring consistent quality in the production of W-L phantoms for donation. Next steps include assessing printer reproducibility.