Abstract : A novel servo tool post system driven by a moving-coil linear motor for turning of convex variable elliptical pistons is designed. The mathematical model of the novel tool post mechanical system and the composition of its closed-circuit control system are presented. The reasons for the high temperature rise in the moving coil are analyzed, and measures to reduce copper loss and limit temperature rise in the moving coil are proposed. Keywords : Non-return turning; Moving-coil linear motor; Tool post 0 Introduction A convex variable elliptical piston refers to a piston whose radius in its transverse cross-section conforms to an elliptical law, while its ellipticity (difference between major and minor axes) varies along its axial direction. Its complex profile makes it impossible for ordinary CNC lathes to complete its machining tasks. The principle of non-circular irregular surface turning is as follows: when the workpiece rotates, the cutting tool moves according to the rotation angle of the machine tool spindle and the requirements of the profile. Figure 1 shows the tool displacement graph. The tool displacement is composed of a high-frequency (AC) component and a low-frequency (DC) component. The high-frequency component turns the elliptical cross-section of the piston, while the low-frequency component corresponds to the piston profile. Therefore, developing a tool post micro-feed mechanism with high frequency response and large stroke is key to realizing the turning of convex variable elliptical irregular surfaces. Electromagnetically driven micro-motion servo tool turrets offer high driving force, but due to their nonlinear actuator nature, they are difficult to control and have a complex structure. Electrostrictive ceramic drive mechanisms offer high precision and are easy to control, but their output displacement is too small to meet machining requirements. Electro-hydraulic servo tool turrets are bulky due to oil source and piping issues, making widespread adoption difficult. Moving-coil linear motors, with their simple structure, good linearity, and small time constant, offer excellent closed-loop characteristics, making them a highly promising servo tool turret driver. This paper presents a novel moving-coil linear motor-driven servo tool turret system, installed on a CNC lathe, capable of turning non-circular irregular curved surfaces. [b][align=center]For more details, please click: Design of a Moving-Coil Motor Servo Tool Turret System for Turning Non-Circular Sections[/align][/b]