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AssigneeU.S. Philips Corporation
InventorsArie Van Tooren, Gerrit H. Van Gool, Johannes H.F.M. Van Leest, Johan C. Wijn
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In a method for measuring a reference position of a tool relative to a workpiece, the tool is fastened to a first holder of a machine tool. The workpiece is to be manufactured using the tool and is fastened to a second holder of the machine tool. The tool provides a distinguishing mark on the workpiece in a predetermined reference position of the first holder relative to the second holder. Subsequently, the distinguishing mark is detected by a sensor. Therefore, the reference position of the tool relative to the workpiece is determined from a position of the first holder relative to the second holder. The tool and the sensor are fastened in fixed, permanent positions relative to one another and relative to the first holder. The accuracy of measurement of the position of the tool depends exclusively on the accuracy of positioning of the first holder relative to the second holder. The accuracy of machining the workpiece is not hurt by the accuracy of measurement of the reference position of the tool relative to the workpiece. The sensor may be optical, with a focusing error detector. The second holder may be rotatable about a Z-axis, with the first holder being displaceable parallel to an X-axis which is perpendicular to the Z-axis, and the distinguishing mark being a circular groove in a surface of the workpiece which extends perpendicularly to the Z-axis.
A method of measuring a reference position of a tool, which is fastened to a first holder of a machine tool, relative to a workpiece to be manufactured by means of said tool, which workpiece is fastened to a second holder of the machine tool, said holders being displaced relative to one another by means of a positioning device, by which method a distinguishing mark is applied to the workpiece by the tool in a previously determined reference position of the positioning device and subsequently a sensor and the workpiece are displaced relative to one another by the positioning device, the reference position of the tool relative to the workpiece being determined from a position of the positioning device in which the distinguishing mark is detected by the sensor, characterized in that the tool and the sensor are fastened in fixed, permanent positions relative to one another and relative to the first holder before the distinguishing mark is provided.
A machine tool with a first holder for a tool, a second holder for a workpiece to be manufactured by means of said tool, a positioning device with which the holders are displaceable relative to one another, and a control member for controlling the positioning device, the positioning device being controllable by the control member, for the purpose of measuring a reference position of the tool relative to the workpiece, in accordance with a control program according to which the tool applies a distinguishing mark to the workpiece in a previously determined reference position of the positioning device, and the positioning device subsequently displaces a sensor and the workpiece relative to one another, the reference position of the tool relative to the workpiece being determined from a position of the positioning device in which the sensor detects the distinguishing mark, characterized in that the tool and the sensor are fastened in fixed, permanent positions relative to one another and relative to the first holder during operation.
Dependencies are inferred from the claim text.