Evaluating the Reliability of Powder Bed Fusion for Biomedical Materials: An Experimental Approach

Abstract

This article provides a comprehensive, step-by-step framework that bridges the gap between the theory and engineering practical applications of Powder Bed Fusion (PBF) technology for producing high-quality metal parts suitable for end users. This proposed framework integrates multiple aspects into a coherent methodology on how to evaluate the PBF parameters and processing conditions, in order to establish a reliability scale for the PBF process on the Realizer 250 SLM machine. Experimental research, conducted over the past 10 years, reveals that the PBF process often encounters challenges related to process stability and part consistency. To address these issues, this paper introduces a novel method for evaluating the manufacturing process by considering the obtained physico-mechanical characteristics. The determined properties of PBF samples were ultimate tensile strength, Young’s modulus, the Poisson ratio, maximum elongation, hardness, and surface roughness. Test specimens were fabricated and tested without applying a stress relief heat treatment. Four bio-metal materials were studied as follows: pure Titanium, Ti6Al7Nb, CoCr, and CoCrWMo. Optimal processing parameters were established for each material focused on laser power, scanning speed, and hatch distance. To have a high chance of successfully printing, each material has its own set of PBF parameters. The results showed that the mechanical resistance can be up to 441 MPa for pure Ti (parameters 120 W, 500 mm/s, 0.12 mm) and 1159 MPa for CoCrWMo alloys (parameters 85 W, 500 mm/s, 0.10 mm). The mechanical properties of these materials are presented, offering valuable data for finite element analysis (FEA) necessary for designing medical implants. This paper provides practical guidelines beneficial for both medical application designers and manufacturers using PBF technology, contributing to enhanced reliability and efficiency in PBF-based metal part production.