Abstract: A machining system includes, a tool configured to machine a workpiece, a motor configured to rotate the tool or the workpiece, a controller configured to control the motor, a measurement device configured to acquire a load current of the motor, the controller is configured to change a rotational speed of the motor when a Mahalanobis distance exceeds a threshold, the Mahalanobis distance is a value determined by using a parameter based on the load current acquired by the measurement device in a specific machining range of the workpiece, and the parameter based on the load current includes a parameter obtained by performing Fourier transform on the load current and a measured value of the load current.

Abstract: An iron base sintered alloy has a chemical composition including at least Fe, Cu and C, and a sintered structure including a residual austenite and a martensite. The sintered structure includes a precipitated Cu element that was dissolved in the martensite and that has been precipitated from the martensite. A method for manufacturing an iron base sintered alloy includes conducting a Cu precipitation treatment for a sintered alloy that has a chemical composition including at least Fe, Cu and C, and a sintered structure including a residual austenite and a martensite to precipitate Cu element dissolved in the martensite.