Accuracy of medical models made by additive manufacturing (rapid manufacturing).

Background: Additive manufacturing (AM) is being increasingly used for producing medical models. The accuracy of these models varies between different materials, AM technologies and machine runs.

Purpose: To determine the accuracy of selective laser sintering (SLS), three-dimensional printing (3DP) and PolyJet technologies in the production of medical models.

Material: 3D skull models: "original", "moderate" and "worse". SLS, 3DP and PolyJet models, and a coordinate measuring machine (CMM).

Methods: Measuring balls designed for measurements were attached to each 3D model. Skull models were manufactured using SLS, 3DP and PolyJet. The midpoints of the balls were determined using CMM. The distances between these points were calculated and compared with the 3D model.

Results: The dimensional error for the PolyJet was 0.18 ± 0.12% (first measurement) and 0.18 ± 0.13% (second measurement), for SLS 0.79 ± 0.26% (first model) and 0.80 ± 0.32% (second model), and for 3DP 0.67 ± 0.43% (original model, first measurement) and 0.69 ± 0.44% (original model, second measurement), 0.38 ± 0.22% (moderate model) and 0.55 ± 0.37% (worse model). Repeatability of the measurement method was 0.12% for the PolyJet and 0.08% for the 3DP.

Conclusion: A novel measuring technique was developed and its repeatability was found to be good. The accuracy of the PolyJet was higher when compared with SLS or 3DP.