A machine tool includes a stationary machine frame, a tool head, which is able to be positioned relative to the machine frame along three mutually orthogonal translation axes, and a motor-driven tool. The machine tool includes a swivel unit, which can be pivoted about a horizontal swivel axis relative to the machine frame and includes a workpiece positioning device, via which a workpiece can be rotated about an axis of rotation oriented perpendicularly to the swivel axis. The swivel unit is assigned a measuring frame, which is able to be rotated with the swivel unit and is arranged to be thermally and/or mechanically decoupled from the swivel unit and includes components of a first and second position measuring system. Additional components of the first position measuring system are disposed on the tool head, and further components of the second position measuring system are situated on the workpiece positioning device. The spatial position of the tool head in relation to the measuring frame is ascertained via the first position measuring system, and the spatial position of the workpiece positioning device in relation to the measuring frame takes place via the second position measuring system.

A machine tool includes a stationary machine frame, a tool head, which is able to be positioned relative to the machine frame along three mutually orthogonal translation axes, and a motor-driven tool. The machine tool includes a swivel unit, which can be pivoted about a horizontal swivel axis relative to the machine frame and includes a workpiece positioning device, via which a workpiece can be rotated about an axis of rotation oriented perpendicularly to the swivel axis. The swivel unit is assigned a measuring frame, which is able to be rotated with the swivel unit and is arranged to be thermally and/or mechanically decoupled from the swivel unit and includes components of a first and second position measuring system. Additional components of the first position measuring system are disposed on the tool head, and further components of the second position measuring system are situated on the workpiece positioning device. The spatial position of the tool head in relation to the measuring frame is ascertained via the first position measuring system, and the spatial position of the workpiece positioning device in relation to the measuring frame takes place via the second position measuring system.

A machine tool including a non-contact affected layer detection sensor capable of detecting an affected layer with high precision is provided. A machine tool includes a non-contact affected layer detection sensor, a main body, probes and that contact the surface of an workpiece, arm portions supported by the main body, and dimension measurement sensors that output a signal that corresponds to the dimension of the workpiece on the basis of displacement of the arm portions with respect to the main body. The affected layer detection sensor is provided in the arm portion, and outputs a signal that corresponds to an affected state of the workpiece. The arm portions hold the probes respectively, and are displaceable with respect to the main body in accordance with the dimension of the workpiece.