Method for reducing residual unbalance of a machining spindle

A method for reducing residual unbalance of a spindle (10) in a numerically controlled machine tool, the spindle (10) being designed to hold a tool (20) fastened to it by a tool holder, the method comprising:

• a data acquisition phase in which at least two measurement operations are carried out;
• in each of the measurement operations, the spindle (10) and the tool (20) are arranged at different angles relative to each other, and in each of which the spindle (10) is rotated and the vibrations to which the spindle (10) is subjected are measured and recorded in a database as a value V0, . . . , Vn representative of their intensity, each of the V0, . . . , Vn values being associated with an angular value θ0, . . . , θn representative of the angle formed between the spindle (10) and the tool (20) during the measurement,
• a step in which a target angular position of the spindle (10) relative to the tool (20) is determined from the database compiled from the measurements, the target angular position having a target angular value θx corresponding to the angular value θ0, . . . θn associated with the minimum V0, . . . Vn value,
• a positioning step in which the spindle (10) and the tool (20) are oriented relative to each other according to the target angular value θx.