Tool Wear Monitoring via Cutting Force Decoupling Under Variable Loads
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Solution Overview
Problem
Existing tool wear monitoring methods are prone to false or missed alarms due to the coupling of tool wear and cutting parameter signals, making it difficult to accurately monitor tool wear under variable operational conditions, especially in real-time machining scenarios where cutting parameters fluctuate.
Innovation Solution
A tool wear monitoring method based on the decoupling of cutting force components, which involves acquiring and processing spindle vibration data, calculating the maximum allowable cutting force, and using a real-time milling force simulation model to separate the tool wear cutting force component, allowing for the estimation of tool wear through a cutting force ratio index.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bandwidth monitoring strategy is used to monitor tool wear, then tool anomaly monitoring is enabled, but the method is very sensitive to threshold setting and prone to false or missed alarms
Solution Approach 1:
The patent segments the coupled monitoring signal into distinct components: cutting process signal and tool wear signal. By using signal decomposition techniques, the tool wear information is separated from the cutting parameter fluctuations, allowing independent analysis of tool wear without interference from variable cutting conditions.
Solution Approach 2:
The patent extracts the tool wear component from the composite monitoring signal by removing the cutting process signal. This extraction process isolates the tool wear information, enabling accurate tool wear monitoring even when cutting parameters vary significantly during the machining process.
2Productivity
If cutting parameters are varied during rough and finish machining, then machining efficiency is improved, but tool wear information is modulated by cutting conditions which interferes with accurate monitoring
Solution Approach 1:
The patent employs dynamic threshold adjustment based on real-time cutting conditions. The monitoring thresholds are not fixed but adapt to varying cutting parameters, allowing accurate tool wear monitoring throughout different machining stages (roughing, semi-finishing, finishing) even as cutting speeds and feeds change.
Solution Approach 2:
The patent divides the machining process into distinct phases (rough machining, semi-finishing, finish machining) and applies phase-specific monitoring strategies. Each phase has its own threshold settings and analysis parameters, enabling accurate tool wear monitoring adapted to the specific cutting conditions of each phase.
3Loss of information
If sensor signals contain both tool wear and cutting parameter information, then comprehensive process information is captured, but tool wear information is swamped in amplitude fluctuations of operational condition changes
Solution Approach 1:
The patent extracts the tool wear signal component from the composite sensor signal by subtracting the reconstructed cutting process signal. This extraction isolates the tool wear information from the overwhelming cutting parameter fluctuations, making the tool wear signal detectable and analyzable.
Solution Approach 2:
The patent introduces signal decomposition and reconstruction techniques as intermediary processing steps between raw sensor signal and tool wear analysis. These intermediary processes filter out the harmful cutting parameter fluctuations while preserving the tool wear information, enabling accurate monitoring.
Data Source
AI summary
The present disclosure discloses a tool wear monitoring method and system under variable operational conditions based on the decoupling of cutting force component. Spindle vibration data of a machine tool is acquired, a data set with labeled tool name information is established according to the machine internal data, a cutting force acting on the tool is estimated in real time based on a vibration signal, and the actual cutting force increased due to tool wear and the maximum allowable theoretical cutting force increased due to tool wear under the surface roughness constraint are calculated. The present disclosure enables tool wear monitoring under variable loads to determine in real time whether the excessive wear occurs based on the part accuracy constraint, and can maximize the service life of the tool.