Multi-Axis CNC Calibration Using 3D Reference Position Mapping
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Solution Overview
Problem
CNC machines with multiple rotation axes suffer from inaccuracies due to imperfections in the alignment and positioning of secondary rotation axes, leading to variations in finished parts that do not meet predetermined geometrical tolerances.
Innovation Solution
A calibration method involving measuring the 3D positions of a reference feature at multiple angular positions around each rotation axis, determining coordinate systems for each position, and adjusting the machine's coordinate system to account for actual positional and orientational changes, using a computer to calculate displacement matrices for precise operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a CNC machine uses multiple rotation axes to increase versatility, then the adaptability of the machine is improved, but manufacturing precision deteriorates due to alignment imperfections and positioning inaccuracies
Solution Approach 1:
The patent changes the parameters of the coordinate system by determining actual positional and orientational parameters of the component at different angular positions around the second rotation axis. These measured parameters are then used to calculate displacement matrices that correct the ideal coordinate system, thereby maintaining manufacturing precision while preserving machine versatility.
Solution Approach 2:
The patent implements feedback by measuring the actual tridimensional positions of reference features at multiple angular positions, comparing these measurements against the ideal coordinate system, and using the discrepancies to calculate correction matrices. This feedback loop enables the machine to compensate for alignment imperfections and maintain precision across multiple rotation axes.
2Productivity
If the machine operates at multiple angular positions around the second rotation axis to increase productivity, then the output is improved, but manufacturing precision deteriorates due to variations in alignment at different positions
Solution Approach 1:
The patent performs preliminary calibration by measuring reference feature positions at multiple angular positions before actual machining operations. The displacement matrices are calculated and stored in advance, allowing the machine to quickly apply corrections during production without sacrificing precision, thereby maintaining both high productivity and manufacturing accuracy.
3Ease of operation
If traditional calibration methods are used to simplify operation, then the ease of operation is improved, but manufacturing precision deteriorates due to inability to account for multi-axis alignment imperfections
Solution Approach 1:
The patent enables the machine to self-calibrate by automatically measuring reference feature positions, calculating displacement matrices, and applying corrections without requiring complex manual intervention. The computer executes the calibration algorithm autonomously, maintaining ease of operation while achieving high precision through multi-axis coordinate system adjustments.
Data Source
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AI summary
The method can include measuring the tridimensional positions of a reference feature (34) for a first at least three different angular positions (P1, P1', P1") of the reference feature around the first rotation axis (24) and a same first reference angular position around the second rotation axis (28), the reference feature being fixed relative to the component (22); and measuring the tridimensional positions of the reference feature for a second at least three different angular positions (P2, P2', P2") of the reference feature around the first rotation axis and a same second reference angular position around the second rotation axis.