Evaluation of CO2 and Nd:YAG lasers for the selective laser sintering of HAPEX®

This paper evaluates and compares the performance of a CO2 and Nd:YAG laser for the selective laser sintering (SLS) of a commercial hydroxyapatite reinforced polyethylene (HA-HDPE) bioactive ceramic polymer composite material. Single-line and layer specimens were produced to compare the effects of different lasers on the material sintering. It was found that the processing window was much larger for the CO2 laser as compared to the Nd:YAG laser. Furthermore, the Nd:YAG processing window was highly dependent on the pulse width and pulse repetition rate parameter settings. Furthermore, the processing windows for both the laser systems were affected by the particle size of the HA-HDPE powders. The degree and mechanism of particle fusion existing in the composites layers were greatly influenced by the laser source and particle size. The results presented in this work clearly indicate that the CO2 laser would present a better performance than the Nd:YAG laser for the SLS of HAPEX(R) in terms of operation range, speed, processing efficiency, and, subsequently, greater potential as an SLS processing method for bioactive implant products.