CNC Sensor Calibration Using Reference Sphere Coordinate Alignment
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Solution Overview
Problem
Conventional CNC processing apparatuses require lengthy calibration procedures due to slight clearance between sensor mounting holders and spindles, causing sensor position shifts and necessitating frequent recalibration for accurate three-dimensional profile measurement.
Innovation Solution
A method involving the use of a contact probe to measure center coordinates of a reference instrument, followed by a single measurement with a non-contact sensor to determine sensor coordinates, and subsequent calculations to align these coordinates with machine coordinates, reducing the need for multiple measurements in subsequent calibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor is replaced for the working tool in the CNC processing apparatus, then the surface shape measurement function is achieved, but the sensor position shifts due to clearance between the mounting holder and spindle, requiring frequent recalibration
Solution Approach 1:
The patent applies preliminary action by pre-establishing the relationship between machine coordinates and sensor coordinates through a calibration procedure that measures reference sphere centers with both contact probe and non-contact sensor. This preliminary calibration data is stored and used for subsequent measurements, eliminating the need for frequent recalibration and reducing calibration time while maintaining measurement precision
Solution Approach 2:
The patent replaces the mechanical contact probe system with a non-contact sensor system for surface shape measurement. The calibration method establishes coordinate transformation between these two different measurement systems, allowing the non-contact sensor to achieve accurate measurements without direct mechanical contact, thereby reducing wear and calibration frequency
2Measurement precision
If multiple measurements are performed during calibration to ensure accuracy, then measurement precision is improved, but the calibration process becomes time-consuming
Solution Approach 1:
The patent introduces reference spheres as intermediary objects during calibration. By measuring the center coordinates of these known reference spheres with both contact probe and non-contact sensor, the system establishes an accurate coordinate transformation relationship. This intermediary approach ensures measurement precision while requiring only a single measurement of the reference instrument, significantly improving calibration efficiency
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Significantly reduces the operation time required for sensor calibration in CNC processing apparatuses, enhancing efficiency and accuracy of three-dimensional profile measurement.
Implementation Method 1
a first step of measuring the center coordinates of a reference instrument with a contact probe and thereby determining the machine coordinates of the center of the reference instrument
Implementation Method 2
a second step of, after mounting of the non-contact sensor onto the spindle, measuring the center coordinates of the reference instrument only one time with the non-contact sensor, and thereby determining the non-contact sensor coordinates of the center of the reference instrument
Data Source
AI summary
A method for calibrating a CNC processing apparatus is provided that can significantly reduce the amount of operation time required for sensor calibration. A method of the present invention for calibrating a non-contact sensor in a CNC processing apparatus 1 includes a first step, a second step and a third step. In the first step, the center coordinates of a reference instrument are measured with a contact probe and thereby the machine coordinates of the center of the reference instrument are determined. In the second step, after a non-contact sensor 110 is mounted onto a spindle 26, the center coordinates of the reference instrument are measured only one time with the non-contact sensor 110, and thereby the non-contact sensor coordinates of the center of the reference instrument are determined. In the third step, calculations are made to determine the amount of displacement required to bring the non-contact sensor coordinates obtained in the second step into agreement with the machine coordinates obtained with the contact probe in the first step.