Abstract: A sensor detects an axial position of a rod controlling a tool-gripping collet in a tool-holding spindle whenever a tool is picked during a working session. The current obtained rod position value is compared with previous rod position value, which has been obtained and stored during the previous tool-picking and, if their deviation is larger than a predetermined threshold, the collet closure is notified as defective. The rod position is obtained as an average of a plurality of closely spaced readings, which are taken after a predetermined delay from the collet closure.

Abstract: A sensor detects an axial position of a rod controlling a tool-gripping collet in a tool-holding spindle whenever a tool is picked during a working session. The current obtained rod position value is compared with previous rod position value, which has been obtained and stored during the previous tool-picking and, if their deviation is larger than a predetermined threshold, the collet closure is notified as defective. The rod position is obtained as an average of a plurality of closely spaced readings, which are taken after a predetermined delay from the collet closure.

Abstract: A numerical control unit issues a sequence of instructions for causing a spindle of a cutter disk in a tool machine to perform successive straight displacements approximating a spiral of Archimedes, with a predetermined angle step from one point to the next, and issues one or more ADIS instructions for merging each of the straight displacements with the next. The spiral path is such that the cutter disk will progressively shave a chip of a predetermined thickness over several revolutions, until its cutting edge is near the intended groove bottom. The tool is then caused to follow a merging path leading to a final point lying on the intended groove bottom, and finally is caused to follow a full circular path coaxial to the bore starting from the final point.

Abstract: A numerical control unit issues a sequence of instructions for causing a spindle of a cutter disk in a tool machine to perform successive straight displacements approximating a spiral of Archimedes, with a predetermined angle step from one point to the next, and issues one or more ADIS instructions for merging each of the straight displacements with the next. The spiral path is such that the cutter disk will progressively shave a chip of a predetermined thickness over several revolutions, until its cutting edge is near the intended groove bottom. The tool is then caused to follow a merging path leading to a final point lying on the intended groove bottom, and finally is caused to follow a full circular path coaxial to the bore starting from the final point.