Improvements to machining process control

A method of machining a workpiece using a machine tool, the machine tool comprising a tool mount carrying a tool, a workpiece mount carrying a workpiece, a drive mechanism for moving at least one of the tool mount and the workpiece mount relative to the other, and a control arrangement for controlling the drive mechanism, wherein the method comprises moving at least one of the tool mount and the workpiece mount with the drive mechanism under the control of the control arrangement so that:

• the tool contacts a portion of the workpiece to commence a machining operation;
• and
• the tool then removes material from the portion of the workpiece until completion of the machining operation, the movement being such that the relative velocity between the tool and the workpiece decreases continuously during the majority of the time that the tool and the workpiece are in contact with each other during the machining operation,
• wherein at a predetermined point partway through the machining operation, at least one dimension of the portion of the workpiece being machined is detected, and a new relative velocity profile to be achieved between the tool and the workpiece over at least a portion of the remainder of the machining operation is determined by the control arrangement with reference to the detected dimension.