Machine tool for machining a micromechanical component, and machining method implemented by said machine tool

A machine tool for machining a piece having at least one surface of revolution with axis of rotation A, said machine tool comprising no-force precision machining means arranged to machine the piece, a lathe comprising at least one first spindle having an axis of rotation B extending along the Z axis into an XYZ coordinate system, said first spindle being movable in translation along the Z axis and in rotation around the first spindle's axis of rotation B, a first clamping device arranged to clamp the piece to be machined and to mount it the piece on the first spindle, a first optical measurement system for the piece integrated into the first spindle and arranged to at least measure the actual dimensions of the piece when the piece is mounted on the first spindle using the first clamping device, and a guidance system arranged to manage machining parameters, the guidance system comprising:

• recording means for predetermined final dimensions of the piece to be achieved following machining with a predefined tolerance,
• control means for the first optical measurement system in order to measure and record actual dimensions of the piece mounted on the first spindle,
• comparison means for comparing the actual measured dimensions of the piece with at least the predetermined final dimensions,
• correction means for adapting the machining parameters in accordance with the comparison of the actual measured dimensions of the piece with at least the predetermined final dimensions,
• control means for the no-force precision machining means in order to machine the piece in accordance with the machining parameters,
• wherein said guidance system is arranged to guide said control means for the first optical measurement system, said comparison means, said control means for the no-force precision machining means, and possibly, said correction means, in order to control a first machining phase of the piece mounted on the first spindle that is programmed to obtain a blank mounted on the first spindle, of which the target dimensions are 0.5% to 20% greater than the predetermined final dimensions of the piece, and then to realize at least one measurement of the actual dimensions of the blank mounted on the first spindle and then to modify the machining parameters of the control means for the no-force precision machining means in order to control, starting from the blank mounted on the first spindle, a second machining phase to remove a sufficiently small quantity of material in order to obtain the finished piece mounted on the first spindle, having a roughness Ra of less than 40 nm, and having the predetermined final dimensions, the machining parameters for the second phase possibly being corrected in accordance with the comparison of the actual measured dimensions of the blank mounted on the first spindle with the predetermined final dimensions.