Experimental and Modeling Study of the Turning Process of PA 6/Nano Calcium Carbonate Composite

Nowadays, polymeric nanocomposites have emerged as a new material class with rapidly growing use in industrial products because of good mechanical, thermal, and physical properties. Recently, the requirement of the direct machining of these materials has increased due to the production of the most of them by extrusion method in simple cross section and the increased demand for personalized products. In this work, the effect of turning parameters (cutting speed and feed) and nano calcium carbonate content on the machinability properties of polyamide 6/nano calcium carbonate composites was investigated by analysis of variance. A novel modeling approach of modified harmony search-based neural network was also utilized to create predictive models of surface roughness and total cutting force from the experimental data. The results revealed that the nano calcium carbonate content on polyamide 6 decreased the cutting forces significantly but did not have a significant effect on surface roughness. Moreover, the results for modeling total cutting forces and surface roughness showed that modified harmony search-based neural network is effective, reliable, and authoritative in modeling the turning process of polyamide 6/nano calcium carbonate composite. 1. Introduction Calcium carbonate, with 85 percent share of consumption among fillers, becomes the most widely consumed filler in the polymer industry; nevertheless, most of the studies in the field of polyamide 6 (PA 6) deal with the nanofiller of clay, and only a few studies deal with nanocomposites of polyamide 6/nano calcium carbonate (PA 6/NCC). On the other hand, findings reveal that adding nanoclay particles to polymer reduces the impact strength of the produced composite and makes it brittle whereas adding NCC increases the tensile strength of the composite thereby not making it brittle [1]. NCC has been used widely as a filler for a wide variety of resins such as polyamide (PA), polyvinyl chloride (PVC), polystyrene (PS), and polypropylene (PP) [2] because of its capability to provide increased stiffness, toughness, and dimensional stability. Substantial improvements in mechanical, thermal, and physical properties of polymer nanocomposites have widened the use of these polymers in industry. In the late 1980s, the Toyota Motor Company commercialized a timing belt cover made from nylon 6/nanoclay composites for one of its car models, demonstrating that thermoplastic nanocomposites are one of the most promising materials to use in domestic and industrial applications [3]. An increase in the desire for