Improving the quality of a circular cooling channel fabrication by fused filament fabrication using Taguchi methods

Fused filament fabrication (FFF) is a three-dimensional printing process that uses a continuous filament of thermoplastic materials to manufacture physical model layer by layer. The wax injection mold (WIM) with conformal cooling channel (CCC) can be fabricated swiftly and economically using a FFF system. However, roundness of the CCC inside the rapid soft tooling fabricated by FFF depends on the process parameters significantly. According to the practical experience, the inside of CCC is easy to accumulate limescale when roundness of the CCC is low. This drawback will result in a reduction in the cooling efficiency because of reduction in the volumetric flow rate of the coolant. To enhance the roundness of the CCC inside the WIM fabricated by FFF, the Taguchi methods were used to investigate the optimum process parameters for fabricating WIM and CCC with better roundness simultaneously. It was found that the most important control factor affecting the roundness of the CCC is the printing temperature, followed by fan speed, print speed, and travel speed. The optimum process parameters for fabricating CCC with better roundness are printing temperature of 160 °C, fan speed of 4,050 rpm, printing speed of 40 mm/s, and moving speed of 50 mm/s. Two pairs of WIM with CCC were fabricated using both conventional process parameters and optimum process parameters. The effectiveness of the optimization process parameters obtained in this study was demonstrated using wax injection molding processes.