###### Abstract  
Cutter edge temperature in milling is an important factor to cutter life. With high cutting speed and feedrate, the cutting efficiency is high; however, the cutter edge temperature is high, shortening the cutter life. Therefore, it is necessary to know the cutter edge temperature in milling. Unfortunately, the cutter edge temperature is difficult to measure and predict in milling. To address the technical challenge, an analytical approach was proposed to predict cutter edge temperature in milling. First, the heat flux into the cutter edge was calculated. Second, by using the Green function, the cutter edge temperature was figured out, and the results obtained from this approach agreed well with that of a recognized test. Then, based on the engagement between the cutter and workpiece in trochoidal milling, the cutter edge temperature was obtained in trochoidal milling. Finally, a temperature comparison was made between trochoidal and side milling based on this analytical approach, and the reasons that trochoidal machining could extend the cutter life were found. This approach is first proposed to calculate the cutter edge temperature in trochoidal milling and can be applied to machining parameters optimization in trochoidal milling and cutter design optimization. t 2020  
Cutting forces affect cutting temperature significantly. Cutting forces and engagement in trochoidal machining have gained the attentions of many scholars. [PERSON] et al. [1] proposed a theoretical approach to calculating engagement angles and cutting forces during trochoidal machining. The cutting efficiency was greatly enhanced by employing a double trochoidal milling strategy. They concluded the cutting efficiency could be greatly improved by the strategy. Refs. [2; 3] developed a model to optimize high speed trochoidal milling of pockets by taking the cutting forces, dynamic characteristics of machine tools, and shape of the workpiece into consideration. They argued trochoidal machining was superior to feedrate adjustment method in regulating cutting forces and extending cutter life at cavity machining. [PERSON] et al. [4] presented an effective approach to optimize trochoidal toolpath based on cutting forces and machine tool kinematics. They pointed out that the engagement angle could be \(\pi\) in traditional cavity milling, which will inevitably lead to large cutter load and high cutting temperature. [PERSON] et al. [5] constructed a novel trochoidal toolpath pattern for effective slotting; the cutting efficiency was enhanced, and immersion angles were limited by the given threshold. They confirmed that trochoidal milling strategy could reduce the cutter load and improve the heat dissipation, which is beneficial to extend the cutter life. Plenty of researchers have found that trochoidal milling could improve the cutting efficiency compared with conventional milling. [PERSON] et al. [6] provided a practical way to generate trochoidal toolpath to cut the critical regions in cavity machining. They indicated that trochoidal machining was superior to contour-parallel machining in cutting the critical regions with careful design of toolpath, and the overall productivity could be improved without sacrificing the tool's life. [PERSON] et al. [7] carried out cutting experiments on Ti-Al6-V4 with two different strategies, conventional and trochoidal milling strategies. They found trochoidal milling strategy was superior to conventional milling strategy in cutting efficiency. [PERSON] et al. [8] made a comparison between trochoidal machining and traditional milling strategy in terms of cutting efficiency and tool wear. They discovered that trochoidal milling performed better in terms of productivity and cutter life by regulating the immersion angle and increasing the cutting parameters. [PERSON] et al. [9] combined the laser-assisted machining with trochoidal machining to cut the difficult-to-cut materials. They discovered that the cutting load was greatly reduced, and the specific cutting energy could be saved.