Optimization of fatigue strength of selective inhibition sintered polyamide 12 parts using RSM

Abstract

Selective inhibition sintering (SIS) is a powder based that fabricate functional parts through fusion of powder bed on a layer by layer basis. Being a new fabrication method, the correlation between process variables and part properties are not fully comprehended. Polyamide 12 (nylon 12) is one of the widely used materials in powder based AM processes including SIS. Therefore, in this work, the effect of critical SIS process parameters on the fatigue behavior of polyamide 12 parts was experimentally investigated, and the parameter settings were optimized to maximize fatigue strength. The number of experimental runs was determined based on Box-Behnken design, and specimens were fabricated as per ASTM D7791. Specimens were tested by subjected them to fluctuating loading at a frequency of 3 Hz. The test results were analyzed using Minitab statistical analysis software. From the ANOVA result, it was identified that the fatigue life of SIS parts is significantly influenced by layer thickness, heater temperature, and heater feed rate. Optimization of process variables settings was performed using the Minitab response optimizer and maximum fatigue strength of 17.43 MPa was obtained. The verification experiment resulted in 17.93 MPa fatigue strength which is comparable to the predicted value and with the result from the literatures.

Response Surface Methodology Based Optimization of Test Parameter in Glass Fiber Reinforced Polyamide 66 for Dry Sliding, Tribological Performance

“…The influence of process parameters of polyamide with varying weight percentages are identified and also the number of trials is reduced via RSM to improve the tribological performance [ 33 , 34 , 35 , 36 , 37 ]. Also, several related studies on the optimization of process variables using the RSM approach for improving the tribological performance in polyamide has been studied and adopted for the present work [ 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 ].…”

Fatigue life assessment of polyamide 12 processed by selective laser sintering. Damage modelling according to fracture mechanics

“…The research on the fatigue behavior of PA12 polymer parts manufactured by SLS has proliferated (Safai et al , 2019), investigating the effect of geometry (Amel et al , 2016), physical properties (density, surface roughness) and microstructure (crystallinity degree, layer thickness, porosity) (Amel et al , 2014; Van Hooreweder et al , 2010; Munguia and Dalgarno, 2015; Terekhina et al , 2020; Henry et al , 2021; Sisay and Balasubramanian, 2020; Schob et al , 2020; Kim et al , 2020), frequency (Munguia and Dalgarno, 2014) or orientation of load application with respect to the layered structure (Munguia and Dalgarno, 2014; Van Hooreweder et al , 20130. The test frequency ranged from 2 to 3 Hz (Amel et al , 2014; Van Hooreweder et al , 2010; Sisay and Balasubramanian, 2020; Schob et al , 2020; Munguia and Dalgarno, 2014) to 50 Hz (Munguia and Dalgarno, 2015) under fully reversed applied load (load ratio, R= −1) and in case of tension-tension cycling loading (R ≥ 0), the loading frequency was 5 Hz (Terekhina et al , 2020; Kim et al , 2020). In all these cases, an important thermal fatigue process may be present, masking the effect of some microstructural features as the intrinsic anisotropy due to layer-wise structure (Van Hooreweder et al , 2010; Munguia and Dalgarno, 2014), and also physical aspects as the surface roughness or the thickness (Amel et al , 2016; Terekhina et al , 2020).…”