Investigation on CFRP 3D printing build parameters and their effect on topologically optimised complex models

This research investigates the effects of building parameters for 3D printing Carbon Fibre Reinforced Polymers (CFRP) and their effect on topologically optimised complex models. The work is conducted by initially developing a DOE varying two parameters in 3D printing namely (i) infill ratio and (ii) infill pattern. Then based on standards ASTM D638 and ISO178, for tensile and flexural tests, specimens are 3D printed and tested for the material Nylon with CFRP (Onyx). From the results it can be observed that (i) specimen with an infill ratio of 85% (constant triangular infill pattern) was found to have the best performance recording a length extension of approximately 5.6 mm under a tensile load of 700 N (ii) in case of infill pattern, triangular shape (constant infill ratio of 37%) recorded the highest the length extension of 7.3 mm under tensile load of 650 N. (iii) 85% infill ratio (constant triangular infill pattern) recorded a bending deflection of approximately 6 mm under a compressive load of 250 N and (iv) the gyroid infill pattern (constant infill ratio of 37%) provided the highest flexural strength with an approximate extension of 5.6 mm under a compressive load of 350 N. After the experimental study and analysing the best parameters, a static analysis and topology optimisation for the 3D printed material (Nylon with CFRP(Onyx)) has been performed on an industrial part for its design validation. Based on the analysis, the original part is redesigned, and again a static analysis simulation is performed to determine the effects of the optimisation process for the same material comparing with 316L-Stainless Steel (SS). Finally, the redesigned model is manufactured with the best 3D printing parameters and validated against the original operating conditions. This study will help industries to use these 3D printing parameters where a metal-based components needs to be replaced with CFRP.