During high pressure die casting process large thermomechanical strains appear on die casting tool. Existing cooling consists of conventional cooling channels, made with drilling process. Main downside is uneven fit to to the shape of die cavity. With help of additive technologies we can make conformal cooling channels. Thermal analysis showed that they offer much better cooling efficiency. From the measurement results, we found that we were able to reduce the temperatures on the tool insert by about 50 percent under the same operating conditions.