Cutting Edge Deflection Estimation Using Strain and Acceleration
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Solution Overview
Problem
In metal cutting machines, especially turning machines, the precision of machining is compromised due to deflection of the cutting edge, which includes both static and vibration components, making it difficult to accurately estimate the position and orientation of the cutting edge during operation, affecting the surface quality and durability of the cutting tool.
Innovation Solution
A cutting tool equipped with a strain gauge and an accelerometer, where the strain gauge measures strain at the tool bar and the accelerometer measures acceleration closer to the cutting edge, complementing each other to provide a more accurate estimation of the cutting edge's deflection by covering static and high-frequency vibrations respectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If strain gauge is placed far from cutting edge to measure strain, then measurement is easier, but detection accuracy of cutting edge deflection is reduced
Solution Approach 1:
The patent uses the accelerometer as an intermediary device placed close to the cutting edge to directly capture high-frequency vibration signals that would be attenuated or missed by a remotely placed strain gauge. This intermediary sensor compensates for the distance-related signal loss.
Solution Approach 2:
The patent segments the measurement function into two parts: the strain gauge handles static deflection measurement at a convenient location, while the accelerometer handles dynamic vibration measurement at the cutting edge location, with each sensor optimized for its specific measurement task.
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
This combination allows for a more complete and accurate estimation of the cutting edge's deflection, enhancing machining precision and surface quality by distinguishing between static and dynamic components of deflection, enabling real-time adjustments to maintain optimal cutting performance.
Implementation Method 1
The strain gauge is arranged to measure strain at the tool bar
Implementation Method 2
The accelerometer is arranged to measure acceleration at the tool bar or at the cutting head
Data Source
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AI summary
A cutting tool (100), a turning machine (200) comprising the cutting tool, and an associated method (400) are provided. The cutting tool comprises a tool bar (110), a cutting head (120), a strain gauge (130), and an accelerometer (140). The cutting head is located at the tool bar and has a cutting edge (121). The strain gauge measures strain at the tool bar. The accelerometer measures acceleration at the tool bar or the cutting head. Deflection of the cutting edge is estimated based on output from the strain gauge and the accelerometer. In some embodiments, the accelerometer is arranged close to the cutting edge while the strain gauge is arranged where the tool bar is susceptible to the largest strain. In some embodiments, low frequency vibrations of the cutting edge are estimated based measured strain, high frequency vibrations are estimated based on measured acceleration, and medium frequency vibrations are estimated based on output from both sensor types.