A low-cost and highly efficient method of reducing coolant leakage for direct metal printed injection mold with cooling channels using optimum heat treatment process procedures

Abstract

Metal additive manufacturing (MAM) provides lots of benefits and potentials in manufacturing molds or dies with sophisticated conformal cooling channels. It is known that the conformal cooling technology provides effective cooling to reduce cycle time for increasing productivity. Ordinarily, mold inserts fabricated by general printing procedures will result in coolant leakage in the injection molding process. The yield in the manufacturing of fully dense injection molding tools was limited to the very narrow working widow. In addition, high costs of fully dense injection mold fabricated by MAM constitute the major obstacle to its application in the mold or die industry. In general, the high cost of MAM is approximately 50–70% more expensive than conventional computer numerical control machining. In this study, a low-cost and highly efficient method of reducing coolant leakage for direct metal printed injection mold with cooling channels was proposed. This new method employs general process parameters to manufacture the green injection mold rapidly and then uses optimum heat treatment (HT) procedures to improve microstructure of the green injection mold. The results of this study revealed that optimum HT procedures can prevent coolant leakage and save manufacturing time of the injection mold fabricated by direct metal laser sintering. The evolution mechanisms of microstructure were investigated experimentally. The saving in the injection mold manufacture time about 67% can be obtained using the general process parameters.