| dc.description.abstract | The major advantage of Metal Injection Molding (MIM) is able to produce complicated metal product without second process. Due to the technology of Metal Additive Manufacturing (MAM) is getting mature in recent years, makes the application of conformal cooling on injection mold more popular. However, the product material in related study is mainly plastic. This thesis is the first study combines the technologies mentioned above, and explores the effect of conformal cooling to MIM product and mold. Moreover, in the cooling channel design stage, injection simulation software - Moldex3D was used to verify the conformal cooling benefits.
The channel diameter of conformal cooling and conventional 2D cooling in this study, are 3mm and 8mm respectively. According to the simulation result, with same coolant flow rate at entrance, the conformal cooling requires higher pump pressure of temperature controller, and the coolant velocity and Reynolds number are higher as well. The average Reynolds number of conformal cooling and conventional 2D cooling are 10825 and 20702 respectively, means both coolant has achieved turbulent flow. In mold preheat stage, the mold with conformal cooling requires only 7.17% of duration to heat up to designated temperature compare to the mold with conventional 2D cooling. The MIM bolt catch in this study is a thick part, therefore the warpage is not obvious, but from the simulation result, conformal cooling product has more uniform mold temperature distribution, leads to more uniform volumetric shrinkage, and able to reduce 2.36% of sink mark displacement.
This study fabricated the core of conformal cooling mold by metal 3D printing, and applied injection molding trial together with the mold with conventional 2D cooling. According to the image of infrared thermal imaging camera, conformal cooling can improve 15.46% of cavity temperature uniformity, and gain more efficiency in product quality controlled by temperature. Under an appropriate coolant temperature, conformal cooling can remove more heat, and achieve the effects of reducing mold temperature and cooling time. The cooling time of the mold trial molding parameter, conformal cooling has 3 second less than conventional 2D cooling. In such condition, conformal cooling mold was still able to produce products, and the product X, Y, Z dimension difference compare to conventional 2D cooling product is close. The result proofs that, while the conformal cooling mold reduces cycle time, it can still ensures the product dimensional accuracy. | en_US |