For example, assuming the average surface temperature of a mold region is about 84 °C when applying a conventional straight-drilled cooling channel. The ejection temperature is 87 °C, the molding thickness is 2.5 mm, and TM = 240 °C. The plastic material is polypropylene with an average specific heat and thermal conductivity of 1454 J/ kg °C and 0.168 W/m °C, respectively. In this case, the ideal cooling time is around 23 s. If the mold surface temperature decreases to 44 °C, the cooling time reduces to around 10 s, a reduction of approximately 56.5%. The cooling time can only be reduced to a minimum when the mold surface cools down to the lower range of the recommended mold temperature. However, if the mold surface temperature is too low, the cooling speed increases, but short shots and high residual stress in the molded parts can occur. reduction is small.