Tool Holder Phase Alignment for Accurate Chuck Error Detection
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Solution Overview
Problem
Existing methods for detecting tool holder attachment abnormalities and displacements in machine tools face challenges due to the difficulty in accurately matching phases of measurement data, especially with symmetrical notches and varying flange shapes, leading to inaccurate detection of chuck errors and displacements.
Innovation Solution
A method and device that utilize a sensor to measure the outer circumferential shape of a tool holder flange, aligning the rotation angle to count notches, and perform Fourier analysis to match phases and calculate eccentricity vectors, ensuring accurate detection of chuck errors and displacements regardless of sensor type or environmental conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase correction is performed using notch signals or characteristic magnetic uneven patterns, then measurement data can be aligned, but detection accuracy decreases when flange shapes vary or when symmetrical notches are present
Solution Approach 1:
The patent applies asymmetry by deliberately creating an asymmetric magnetic pattern on the tool holder flange using a magnet. This asymmetric magnetic field generates a unique magnetic uneven pattern that does not depend on the physical shape or notch configuration of the flange. The asymmetric magnetic signature serves as a reliable reference for phase correction regardless of whether the notches are symmetrical or the flange shape varies, thereby resolving the contradiction between phase alignment accuracy and detection reliability.
2Reliability
If measurement data is collected during both setup and machining, then chuck errors can be detected by comparison, but the complexity of data processing and phase matching increases
Solution Approach 1:
The patent applies preliminary action by performing phase correction using the asymmetric magnetic uneven pattern before comparing measurement data between setup and machining states. The magnetic pattern is established as a reference during setup, and this pre-established reference simplifies the subsequent data comparison process during machining. By preparing the magnetic reference in advance, the system avoids complex real-time phase matching calculations, thereby reducing data processing complexity while maintaining reliable chuck error detection.
3Measurement precision
If the sensor measures outer circumferential shape directly, then structural information is obtained, but the measurement is affected by chip adhesion and flange shape variations
Solution Approach 1:
The patent introduces a magnet as an intermediary element that creates a magnetic field between the sensor and the tool holder flange. This magnetic field serves as a mediator that allows the sensor to detect the asymmetric magnetic uneven pattern without being directly affected by chip adhesion or flange shape variations. The magnetic field penetrates through or around the chips, providing a clean signal that reflects the intentional asymmetric magnetic pattern rather than the physical condition of the flange surface, thereby eliminating the harmful effects of chip adhesion and shape variations.
Data Source
AI summary
In a tool holder attachment state detection method of the present invention, during setup, a tool holder 11 is attached to a spindle 26 without any chuck error, counting of the number of notches 11C formed in a flange portion 11B is started after the rotation of a tool 9 is started, and a time T taken to obtain measurement data from the notch 11C detected last and a count N at that time are stored, and during machining, measurement data is obtained by making the count N and the time T correspond to each other by the same procedure as during setup. Therefore, regardless of sensor types, the number of notches, shape accuracy, environment, and the like, this method easily and accurately matches the phases of measurement data during setup and machining, and improves the detection accuracy of chuck errors.