Material testing for injection molded and 3D printed pristine/glass reinforced nylon at various strain rates

Abstract

With the advent of new polymer material and non-conventional methods of manufacturing, the effect of loading conditions on mechanical properties has now been in huge demand to facilitate their industrial applications. Present paper has been focused on investigating the strain rate effects on mechanical properties of pristine nylon-6 and 20% glass reinforced nylon-6 material fabricated using injection molding and SLS (Selective Laser Sintering) printing manufacturing methods, respectively, at three strain rates of 0.0003, 0.003, and 0.01 per second. Tensile strength of injection molded nylon-6 has shown a positive relationship with strain rate whereas compressive strength has shown a reciprocal effect. At highest strain rate of 0.01 s−1, tensile strength exhibits 10.27% more as compared to lowest strain rate of 0.0003 s−1. Tensile strength at highest strain rate is found 60 MPa whereas at lowest strain rate it exhibits 54.41 MPa. At higher values of strain rate, rising of maximum strain is found very much sensitive than the rise in tensile strength. It also shows high percentage of deformation at higher value of strain rate. On the other hand, SLS printed 20% glass reinforced nylon-6 shows variable tensile strength with respect to strain rate due to uneven distribution of glass particles into nylon matrix created due to manufacturing process of SLS printing. FESEM images shows the cavity formation as observed before loading conditions whereas the glass fracturing phenomenon observed at the after loading conditions. However, compressive strength is found minimal with strain rate with an average value of 175.61 MPa. The findings of this study have contributed in avoiding the improper selection of material and its strain rate application during numerical modeling for industrial application purpose.