## 2 Conformal Cooling Channel
The simulation results showed that the temperature deviation of the injection-molded product was successfully reduced by about 30% by using the evolutionary optimization design method, which improved uniformity of the mold temperature distribution and reduced volume shrinkage of the molded part. [PERSON] et al. [16] used a similar optimization method to simulate and evaluate the thermal performance of a single-cavity injection mold by considering the uniformity of mold temperature distribution and the cooling time of injection-molded products as optimization indexes, and the thermal performance of a single-cavity injection mold was simulated and evaluated by the thermodynamic coupling module of ANSYS R15.0 software. [PERSON]'s design method solves the shortcomings of the single-objective optimization method and achieves multi-objective optimization of the mold's temperature distribution uniformity and cooling time, which has better practicality. Based on COMSOL 5.0 simulation software, [PERSON] et al. [17] in the United States implemented topological optimization of the parameters of the three-dimensional model of the product according to thermodynamic theory and solved the cooling channels' design parameters according to the derivative-free optimization solution method, and by solving the thermodynamic topological optimization problem, the structural distribution of the multi-phase lattice was optimized by optimizing the cell lattice distribution so that the injection mold can be lightweight and ensure its structural strength at the same time. Compared with other optimization methods for designing the channels, this method can improve the structural stability of the injection mold while ensuring the quality of the design for the cooling channels. [PERSON] (USA) and [PERSON] (India) [18] used the experimental design method to optimize the design parameters of the conformal cooling channels. The corresponding optimized design parameters of the conformal cooling channels were finally derived. [PERSON] [19] from the University of Chosun, Korea, designed and fabricated conformal cooling channels in a mold with a fan as the optimization object. The results showed that the cooling efficiency of the mold could be improved by up to 35% by designing a conformal cooling channel. In the same year, [PERSON] and [PERSON] [20] of the University of Ulsan, Korea, used the conventional drilling and milling method to create a U-groove structure with an array of spacer plates to better match the surface profile and shape distribution of the molded part. The advantage of this method is that it is relatively simple, but there will be water leakage. The manufacturing cost is lower than 3D printing but higher than traditional cooling methods. [PERSON] [21] from the University of Leeds, United Kingdom, used selective laser sintering to produce a sample of a mold core and cavity containing a conformal cooling channel, showing that the design of conformal cooling channels in the mold improved both the molding quality and dimensional accuracy of the plastic part. [PERSON] et al. [22] in Australia used 3D software to model the plastic part and then simulated the injection molding process using ANSYS software. Then, the mold model was imported into Moldflow software for meshing, constructing the casting system and cooling system, and simulating the whole injection molding process. By comparing and analyzing defects such as volume shrinkage and warpage deformation, the optimal combination of injection molding process parameters is finally obtained. The simulation results show that the conformal cooling channel of an injection mold can greatly improve the molding quality of plastic parts. [PERSON] et al. [23] of the University of Nantes, France, designed the shape and diameter of the conformal cooling channels by determining the surface temperature distribution of the cavity based on a conjugate gradient algorithm.