An injection mold which has inside water cooling channels has been fabricated using selective laser sintering method.Box shape workpiece was chosen as a test piece in order to confirm the effect of the inside cooling channels. Cooling channels are constructed in the core to make the effective cooling and uniform temperature condition.The warp of the side surface of the product injected with high cooling core was copared with that molded in the low cooling core without inside water channels. The amount of the warp obtained with the high cooling core was the half of that with the low cooling core and constant from the initial shot numbers.The temperature difference between the top surface and the bottom part of the core was about 20°C in the high cooling core whereas it exceeds 50°C in the low cooling core.It was confirmed that the water cooling channel inside the core reduces the temperature difference in the core and improves the dimension accuracy of the workpiece. The fabrication of the inside cooling channels using selective sintering method is useful to obtain stable and accurate injection molding.
