Method and apparatus for co-ordinate measuring using a capacitance probe
First Claim
1. A method for measuring surface characteristics which comprise dimensions and contour of a conductive workpiece utilizing a non-contacting, conductive probe sensor, the steps comprising;
- a) applying a voltage across said workpiece and said sensor,b) causing a relative motion between said sensor and said workpiece so that said sensor defines a path of travel with reference to said workpiece by which said sensor is moved generally parallel to a first workpiece surface at a velocity dependent upon the measured capacitance so that said velocity is increased when the capacitance indicates that the sensor is in no danger of impacting with or moving past the workpiece, and said velocity is reduced in proportion to capacitance changes indicating that the sensor is approaching a second workpiece surface intersecting with said first workpiece surface,c) measuring and recording said path of travel,d) measuring and recording the capacitance between said sensor and said workpiece relative to said path of travel,e) determining the surface parameters of the workpiece as a function of the said recorded path of travel and the corresponding recorded capacitance.
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Accused Products
Abstract
The surface parameters and characteristics of a conductive workpiece are determined by applying a voltage between the workpiece and a capacitance probe having proximity sensing capabilities, and moving the probe in two or three co-ordinate axes relative to the workpiece while measuring the capacitance between the probe and workpiece, and controlling the probe velocity and/or direction within a stand-off band adjacent to the workpiece as a function of the capacitance value measured for purposes of effecting significant real time process controls, and determining the workpiece surface parameters as a function of the probe movement and capacitance measured.
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Citations
19 Claims
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1. A method for measuring surface characteristics which comprise dimensions and contour of a conductive workpiece utilizing a non-contacting, conductive probe sensor, the steps comprising;
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a) applying a voltage across said workpiece and said sensor, b) causing a relative motion between said sensor and said workpiece so that said sensor defines a path of travel with reference to said workpiece by which said sensor is moved generally parallel to a first workpiece surface at a velocity dependent upon the measured capacitance so that said velocity is increased when the capacitance indicates that the sensor is in no danger of impacting with or moving past the workpiece, and said velocity is reduced in proportion to capacitance changes indicating that the sensor is approaching a second workpiece surface intersecting with said first workpiece surface, c) measuring and recording said path of travel, d) measuring and recording the capacitance between said sensor and said workpiece relative to said path of travel, e) determining the surface parameters of the workpiece as a function of the said recorded path of travel and the corresponding recorded capacitance. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. Apparatus for measuring surface characteristics which comprise dimensions and contour of a conductive workpiece comprising;
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a) a capacitance probe having a conductive sensor, b) means for applying a voltage across said conductive sensor and said workpiece, c) drive means for causing a relative motion between said sensor and said workpiece so that said sensor will define a path of travel by which said sensor is moved generally parallel to a first workpiece surface at a velocity dependent upon the measured capacitance so that said velocity is increased when the capacitance indicates that the sensor is in no danger of impacting with or moving past the workpiece, and said velocity is reduced in proportion to capacitance changes indicating that the sensor is approaching a second workpiece surface intersecting with said first workpiece surface, d) means for measuring and recording said path of travel, e) means for measuring and recording the capacitance between said sensor and workpiece with respect to said path of travel, f) means for calculating the parameters of the workpiece surface as a function of the recorded path of travel and the recorded capacitance corresponding thereto. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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Specification