Investigation into the processability, recyclability and crystalline structure of selective laser sintered Polyamide 6 in comparison with Polyamide 12

Polyamide 6 (PA6) have been extensively employed in manufacturing engineering plastic alternatives to metal in automotive field owing to their high specific strength, good damping and thermal properties. However, the selective laser sintering (SLS) availability of high performance PA6 is not thoroughly investigated. This paper firstly investigates the processability, recyclability and crystalline structure of SLS PA6 powder in comparison with the widely used Polyamide 12 (PA12). The results show that the PA6 powder has a relatively sphere shape, an appropriate average particle size 58.9 mu m, a wide sintering window up to 36.73 degrees C (c. 6 degrees C wider than PA12) and similar crystallinity 47.61% comparable to PA12, indicating an excellent SLS processability. However, the used PA6 powder shows a directly fragmenting behavior, a substantially narrowed sintering window (decreased by 13.15 degrees C) and a dramatically declined crystallinity (down to 21.8%), indicating a relatively inferior recyclability compared with PA12. The sub-T-pm1 crystallization transition concerning alpha phase was found for SLS PA6 part, which is derived from the release of strain energy absorbed during SLS processing and has advantageous effects on part ductility. This work confirms that it is available and promising for the application of high performance PA6 in SLS.