Chuck Table Alignment Correction Beyond Linear Travel Accuracy Limits
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Solution Overview
Problem
Existing processing apparatuses face reduced accuracy at the ends of their linear travel range due to low linear travel accuracy, leading to potential misalignment and errors in processing, which cannot be easily resolved without increasing cost or installation space.
Innovation Solution
A processing apparatus with a rotatable chuck table, a camera system for imaging, and a control unit that calculates correction values and angles to adjust the chuck table's position and orientation, allowing for accurate processing even outside the guaranteed range without extending the linear actuator's length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the guaranteed range of the linear actuator is widened to the opposite ends or the linear actuator is increased in length, then the linear travel accuracy is improved across the entire range, but the cost and installation space increase
Solution Approach 1:
The patent divides the working range into two segments: a guaranteed range where the linear actuator maintains high accuracy, and a non-guaranteed range at the opposite ends where accuracy degrades. By segmenting the workspace and applying different correction strategies for each segment, the system avoids the need to extend the linear actuator's guaranteed range throughout the entire travel distance, thus reducing cost and installation space requirements.
Solution Approach 2:
The patent changes the reference frame parameters by introducing a reference mark on the chuck table and using a camera to detect positional deviations. Correction values are calculated based on the detected deviation from the reference mark, allowing the system to compensate for accuracy degradation in the non-guaranteed range without modifying the physical parameters of the linear actuator itself.
2Manufacturing precision
If the linear actuator length is increased to widen the guaranteed range, then processing accuracy at the ends is improved, but the installation space and cost increase
Solution Approach 1:
The patent introduces a camera as an intermediary measurement device and a reference mark as an intermediary reference element. The camera captures images of the reference mark to detect positional deviations, and correction values are calculated based on these detections. This intermediary measurement and correction mechanism enables accurate processing at the ends of the travel range without requiring physical extension of the linear actuator, thus avoiding increased installation space requirements.
3Productivity
If processing is performed in the non-guaranteed range, then productivity is improved by utilizing the full travel range, but processing accuracy deteriorates due to low linear travel accuracy
Solution Approach 1:
The patent implements a feedback mechanism where the camera continuously monitors the position of the reference mark on the chuck table, and correction values are calculated based on the detected positional deviations. These correction values are applied to compensate for the low linear travel accuracy in the non-guaranteed range, enabling accurate processing throughout the full travel range and thus maintaining both high productivity and processing accuracy.
Solution Approach 2:
The patent performs preliminary measurement by capturing an image of the reference mark before processing operations in the non-guaranteed range. Correction values are calculated in advance based on the detected positional deviation, allowing the system to pre-compensate for accuracy degradation before actual processing occurs, thereby ensuring both full utilization of the travel range and maintained processing accuracy.
Data Source
AI summary
A method of using a processing apparatus that includes a holding unit with a rotatable chuck table for holding a workpiece; a processing unit for processing the workpiece; a camera for imaging the workpiece that is movable in an indexing feed direction; and a control unit for controlling the components. The method includes forming a linear processed mark in the workpiece, and then moving the chuck table to an imaging zone, where the camera images the processed mark. The method further includes calculating correction values or a correction angle, and carrying out processing feed of the chuck table in the imaging zone under a condition in which the camera has been corrected in position in the Y-axis direction based on the correction values or the chuck table has been rotated by the correction angle.