## 1 Introduction
Some researchers have focused on the analysis of cooling systems and how to optimize the layout of cooling channels in terms of their size and position by means of mathematical calculations and analytical methods. These practical methods are reported to be more convenient and faster than the finite difference method and finite element method (FEM). They require less work from the plastics designer than numerical and analog software. These methods can be  
Figure 1: The main stages of injection molding  
applied to simple molded parts. Other methods use the 2D boundary element method and sensitive analysis combined with gradient optimization algorithms or hybrid optimizers to optimize cooling channel systems. More recently, the application of 3D CAE and 3D FEM computer-aided simulations has been widely used to study the thermal behavior of cooling systems and the configuration of conformal cooling channels. The results of these studies [6,8] have shown that shaped cooling channels have shorter cooling times and better temperature distribution than conventional cooling channels. [PERSON] and [PERSON] [9] introduced an optimization strategy and investigated certain types of shaped cooling layouts for automotive parts by applying analytical formulations. They used CAE flow simulations to validate the optimization results and to demonstrate the cooling effect of the shaped cooling channels. To achieve a consistent temperature distribution, it is essential to align the cooling channels with the surface of the mold cavity. The utilization of this approach relies on advancements in solid freeform (SFF) manufacturing technology, allowing for precise and uniform cooling channel placement. A number of works have investigated the advantages of the conformal cooling system and how to optimize the conformal cooling channels in injection models. The results report that the conformal cooling channels provide better temperature uniformity and better-molded part quality within the mold cavity compared to straight cooling channels. SFF or rapid prototyping technology offers the opportunity to create very complex cooling channels in the core and cavity, but this technology is still very expensive, especially for large molds. On the other hand, there is a limited range of metal powders available for additive technologies, such as 3D printing, selective laser sintering, electron beam melting, and laser-engineered net forming. This means that the choice of mold materials with the right thermal and mechanical properties for the manufacturing of conformal cooling channels by SFF is narrower than for conventional molds. The issues have prevented the widespread use of additive technologies in the manufacturing of large injection molds. This paper aims to solve the persistent problem by introducing an optimized conformal cooling channel. The relationship between the cooling channel configuration and the average thermal behavior of the mold cavity cycle is investigated in depth. The layout of cooling channels for quite complex molded parts is optimized by combining simplified models, computer-aided 3D heat transfer analysis, and an effective optimization strategy. As a result, this approach will provide a more feasible and practical way to design optimal conformal cooling channels, reduce cooling time and improve the quality of molded parts with less work.