Machine Tool Sensor Using TDR for In-Process Tool Inspection
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Solution Overview
Problem
Current tool inspection methods in machine tools, such as metal-cutting machines, face challenges including increased cycle time and space constraints due to separate measuring stations, and are affected by environmental disturbances like chip deposits and coolant residues, which impact measurement accuracy and reliability.
Innovation Solution
A sensor using the TDR measuring principle transmits a high-frequency signal through the tool to determine transit time, allowing for in-process tool inspection without a separate measuring station, and is robust against environmental disturbances, enabling continuous monitoring and accurate detection of tool damage or incorrect clamping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate measuring station is used for tool inspection, then measurement accuracy can be maintained, but cycle time increases and space requirements increase
Solution Approach 1:
The patent merges the measurement function directly into the tool holder, combining the tool clamping function and measurement function into a single integrated unit. This eliminates the need for a separate measuring station, allowing measurements to be taken in-situ during the machining process, thereby reducing cycle time while maintaining measurement accuracy through the integrated sensor system.
Solution Approach 2:
The tool holder performs self-measurement by integrating the measurement system directly into it. The tool holder measures its own tool length and position without requiring external measurement equipment or separate measurement operations, enabling continuous monitoring during machining and eliminating idle measurement time.
2Ease of operation
If a separate measuring station is used for tool inspection, then measurement function is provided, but space within the machining area increases
Solution Approach 1:
The measurement system is merged with the tool holder structure, eliminating the need for a separate measuring station. The sensor and measurement electronics are integrated directly into the tool holder, which already occupies necessary space in the machining area for tool clamping and positioning. This integration provides the measurement function without additional space consumption.
3Difficulty of detecting and measuring
If optical sensors are used for tool inspection, then measurement capability is provided, but measurement accuracy is affected by environmental disturbances
Solution Approach 1:
The patent replaces optical measurement systems with a contact-based mechanical/electrical measurement system. The measurement sensor makes direct electrical contact with the tool through the tool holder, measuring tool length and position via electrical contact resistance or inductance changes. This substitution eliminates sensitivity to optical disturbances such as chip deposits, coolant residues, and lighting conditions while maintaining high measurement accuracy.
Solution Approach 2:
The tool holder acts as an intermediary between the measurement system and the tool. It provides a stable, controlled interface that isolates the measurement from environmental disturbances. The sensor measures parameters through the tool holder, which shields the measurement process from chips, coolant, and other harsh machining environment factors that would affect optical sensors.
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
The solution significantly reduces cycle time, eliminates space requirements, and improves measurement accuracy by allowing tool inspection during normal workflow, providing reliable detection of tool damage and correct clamping status without the need for additional sensors.
Implementation Method 1
A high-frequency signal is transmitted through the tool to the tool tip and back; the transit time of the high-frequency signal to the tool tip is determined
Implementation Method 2
A coupling unit of the sensor couples the high-frequency signal into the tool and the returning signal out of the tool
Data Source
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Figure 5
AI summary
A sensor (10) for checking a tool (28) of a machine tool (24) is specified, which has a high-frequency transmitter (12) for generating a high-frequency signal, a high-frequency receiver (14) for generating a received signal from a received high-frequency signal, a coupling unit (16) for coupling a high-frequency signal into and out of the tool (28), and a control and evaluation unit (20) for determining a transit time of a high-frequency signal emitted by the high-frequency transmitter (12) and received by the high-frequency receiver (14) on the basis of the received signal of the high-frequency receiver (14).