Fiber Optic Tool Wear Sensing During Machining
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for measuring tool wear during machining processes, especially in grinding and cutting tools, face challenges such as accuracy impairment due to thermal and atmospheric effects, and the need for offline or periodic inspections, which disrupt productivity and make it difficult to determine the optimal moment for dressing processes.
Innovation Solution
A tool device equipped with a fiber optic sensor using interferometric technology, such as a Fabry-Perot interferometer, that measures changes in optical path length to detect tool wear and condition in real-time, allowing for precise monitoring of macroscopic and microscopic wear without direct electrical requirements, and enabling accurate determination of the first touch with the workpiece.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If indirect sensors (force monitoring, temperature monitoring, acoustic emission) are used to monitor tool condition, then monitoring can be performed during machining, but measurement precision deteriorates due to thermal effects and atmospheric effects from circulating coolant
Solution Approach 1:
The patent replaces indirect mechanical and thermal sensors with direct optical measurement. A laser displacement sensor measures the actual position of the cutting edge relative to the workpiece, substituting mechanical force sensors and thermal sensors that were affected by coolant and thermal effects. This optical measurement method is immune to the harmful environmental factors present during machining.
Solution Approach 2:
The patent introduces an optical field as an intermediary measurement medium. Instead of directly measuring mechanical forces or temperatures that are corrupted by coolant and heat, the system uses laser light as an intermediary to measure the position of the cutting edge. The optical field serves as a clean, unaffected mediator that can accurately capture edge position changes without being influenced by thermal or atmospheric conditions.
2Measurement precision
If vision sensors are used to measure tool wear, then direct measurement is possible, but measurements can only be performed between machining runs because the wear area is not visible during actual machining
Solution Approach 1:
The patent positions the laser displacement sensor to measure the cutting edge position before wear occurs, and continuously monitors during machining. By establishing the measurement system in advance and enabling continuous operation, the system captures wear progression in real-time rather than requiring post-machining inspection. This preliminary and continuous measurement approach eliminates the need to stop machining for measurements.
Solution Approach 2:
The patent replaces vision sensors that require line-of-sight access with a laser displacement sensor that measures position through optical time-of-flight or interference. This substitution enables measurement during active machining when the tool is engaged with the workpiece, as the laser can measure the position of the cutting edge relative to the workpiece surface without requiring the wear area to be visually accessible.
3Productivity
If conductor paths embedded in cutting material are used to measure wear, then on-line measurement is possible, but the system becomes complex with multiple conductors and external measuring circuitry
Solution Approach 1:
The patent replaces the electrical conductor path system with an optical measurement system. Instead of embedding multiple conductors in the cutting insert and connecting them to external circuitry, the system uses a laser displacement sensor that measures cutting edge position optically. This substitution eliminates the complex electrical infrastructure while maintaining on-line measurement capability during machining.
Solution Approach 2:
The patent extracts the measurement function from the tool insert itself. Rather than requiring conductors embedded in the cutting material, the measurement system is externalized to a laser displacement sensor that measures the position of the cutting edge relative to the workpiece. This extraction simplifies both the tool insert design and the measurement system by separating the measurement function from the cutting function.
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 solution provides reliable, low-cost, and accurate real-time monitoring of tool wear and condition, optimizing machining processes by determining the optimal dressing times and maintaining production quality, while reducing costs and improving productivity.
Implementation Method 1
A tool device equipped with a fiber optic sensor using interferometric technology, such as a Fabry-Perot interferometer, that measures changes in optical path length to detect tool wear and condition in real-time
Implementation Method 2
A tool device equipped with a fiber optic sensor using interferometric technology, such as a Fabry-Perot interferometer, that measures changes in optical path length
Data Source
AI summary
A tool device (1) for machining a workpiece (4) by cutting, milling, drilling or grinding, comprising a sensor (20) for detecting a condition of the tool device (1) during machining, wherein the sensor (20) is connectable to a receiving unit (40), which transmits data to an analysis unit (50) for analyzing the received data. The sensor (20) is configured as a fiber optic sensor (20) comprising at least one optical fiber (26) providing an incident optical path (22) and a reflected optical path (24) for a light beam emitted by a connectable light source (30) and with a distal end thereof lying in a surface (14, 74) of the tool device (1) such that the optical path length can be measured.