A hairpin motor is a type of motor that is used for driving an eco-friendly car. Unlike a conventional coil-winding motor, hundreds of hairpins formed by an enameled copper wire with a rectangular cross section comprise a stator to improve the driving efficiency by maximizing a coil drip rate. With the increased use of the hairpin motor, there has been an increased interest in manufacturing techniques and automated systems of the hairpin motor. Enamel coating removal is one of the major processes of hairpin motor production; enamel coating at the end of the hairpin should be removed to connect the hundreds of hairpins by using the welding process. Grinding is one of the machining processes used for removing the enamel coating. This study proposed an adaptive control method for the grinding process to improve the efficiency and quality of the enamel coating removal process. Grinding depth is maintained during machining by controlling the vertical position of the spindle based on driving torque. A lab-scale grinding machine including a sensory system for adaptive control is developed and used to verify the performance of the proposed method.

This research aims to provide a useful algorithm for the prediction of the geometrical expansion of flat rings in the radialaxial ring rolling process in case of multiple variations of the mandrel feeding speed during the process. The proposed algorithm was subjected to a 2-phases validation process, where results were compared with those of laboratory experiments, conducted at 150℃ on rings made of AA-1070 and AA-6061 aluminum alloys, and with numerical simulations, considering 7 different rings with outer diameter ranging from 800 to 2000 ㎜ and made of 42CrMo4 steel alloy, Ti6Al4V titanium alloy and AA-6061 aluminum alloys. In the first and second validation phases, the maximum deviation in the estimation of the outer diameter of the ring has been calculated in 1.7% and 6.82%, respectively. According to the results of the validation, the proposed algorithm is able to properly predict the geometrical expansion of the ring for multiple variations of the mandrel feeding speed during the process and has good accordance with both relatively small and large rings.