Machine Tool Vibration Sensor Diagnosis During Automatic Tool Change
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Solution Overview
Problem
Conventional numerical control devices for machine tools fail to recognize abnormalities in the vibration detection unit, such as broken sensor elements or connection issues, leading to undetected chatter vibrations and spindle bearing problems, which can result in machining failures and equipment damage, as they rely on manual checks that are time-consuming and often missed until the next day.
Innovation Solution
A numerical control device with an acquisition circuit to gather vibration information and a determination circuit that automatically detects abnormalities during the automatic tool exchange operation, utilizing a switch to enable or disable diagnosis, allowing for immediate recognition of issues with the vibration detection unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual checks are performed to detect abnormalities in the vibration detection unit, then detection capability is maintained, but time consumption increases and detection timeliness deteriorates
Solution Approach 1:
The vibration detection unit performs self-diagnosis by monitoring its own output signals. The determination circuit automatically detects abnormalities by analyzing whether the vibration signal exceeds predetermined thresholds during automatic tool exchange, eliminating the need for external manual checks and enabling continuous autonomous monitoring.
Solution Approach 2:
The system implements feedback by continuously monitoring the vibration signal output from the vibration detection unit and comparing it against predetermined thresholds. When the signal exceeds the threshold, the system generates an abnormality notification, creating a closed-loop monitoring system that automatically responds to detected anomalies.
2Loss of time
If automatic tool exchange operation is utilized for abnormality detection, then detection timeliness is improved, but system complexity increases
Solution Approach 1:
The automatic tool exchange operation serves dual purposes: performing the tool更换 function and simultaneously acting as a test operation for detecting abnormalities in the vibration detection unit. This multi-functionality allows the existing automatic tool exchange mechanism to be leveraged for diagnostic purposes without adding separate dedicated test equipment.
Solution Approach 2:
The determination circuit acts as an intermediary that processes the vibration signal during automatic tool exchange and determines whether abnormalities exist. It mediates between the vibration detection unit and the control device, automatically generating abnormality notifications when thresholds are exceeded, thereby simplifying the overall diagnosis system architecture.
3Measurement precision
If vibration signal threshold monitoring is implemented, then abnormality detection accuracy is improved, but false positive rate may increase
Solution Approach 1:
The system dynamically adjusts the monitoring approach by utilizing the automatic tool exchange operation as the test condition. During this specific operation, the system monitors whether the vibration signal exceeds the predetermined threshold, leveraging the known mechanical activities during tool exchange to contextualize the vibration levels and reduce false positives.
Solution Approach 2:
The system changes the operational parameter by using automatic tool exchange as the specific test condition for abnormality detection. During this operation, the control device monitors vibration signals with predetermined thresholds, and the known mechanical activities during tool exchange provide a baseline for distinguishing normal from abnormal vibrations, improving detection accuracy while reducing false alarms.
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
Enables the automatic and timely detection of abnormalities in the vibration detection unit, preventing machining failures and equipment damage by activating the chatter vibration prevention and spindle bearing diagnosis functions proactively during tool exchange operations.
Implementation Method 1
When the spindle vibrates due to, for example, chatter vibrations, the vibrations are transmitted to the vibration detection unit 301 and vibrate the piezoelectric element 302. With the piezoelectric effect due to the vibrations, the piezoelectric element 302 generates a voltage
Data Source
AI summary
A numerical control device of a machine tool recognizes a failure of a vibration detection unit in a relatively short time to minimize damage to functions achieved using the vibration detection unit. A program interpreting unit interprets an automatic tool exchange operation, and a storage unit is instructed to store vibration information V(x) from the vibration detection unit. After the automatic tool exchange operation is finished, the storage unit is instructed to stop storage. When none of the vibration information V(x) stored in the storage unit exceeds a prescribed vibration level, a vibration information analysis unit determines abnormality of the vibration detection unit.