| Abstract [eng] |
This study examines the comparative performance of three cross-section profiles of conformal cooling channels, circular, elliptical and teardrop, for injection-moulding on a simulation basis. The work is based on the need to understand whether the profile geometry of the cooling channels itself can influence cooling behaviour when the conformal channel route, mould geometry, material, process parameters and standoff distance are kept constant, while coolant inlet temperature and coolant flow rate are varied. The straight-line cooling channel has been added as a reference baseline to put the conformal cooling benefit into perspective; the primary comparison should be that of the profile-level inside the conformal cooling group. A simplified battery casing inspired part geometry was modelled in SolidWorks; the simulations were done in Moldex3D with 20% talc-filled polypropylene and a P20 tool-steel as mould material. A design of experiments matrix comprised of the circular, elliptical and teardrop profiles, with flow rates of the coolant at 2, 5, and 10 L/min and coolant inlet temperatures of 15°C, 25°C and 35°C, a total of 27 conformal cooling simulations and 3 straight-line reference simulations were analysed. The responses extracted from the simulation results were average part temperature, maximum part temperature, time to reach ejection temperature, pressure drop, average Reynolds number and warpage displacement. The effect of the factors and the predicted optimum operating region were determined using response surface methodology. Results indicated that the average part temperature was not significantly affected by the profile geometry, but the maximum part temperature and cooling time were significantly affected by the profile geometry. The lowest maximum part temperature and cooling time was obtained with the teardrop profile, and the lowest pressure-drop tendency was obtained with the elliptical profile. The differences of the warpages between the profiles were small. It is concluded that the conformal channel cross-section profile is a sensible design parameter, and that the teardrop profile has the best thermal performance within the simulation domain explored. |
