Tool Shank Force Sensor for Dynamic Machining Load Measurement
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Solution Overview
Problem
Current methods for measuring tool forces in machine tools, such as dynamometers and strain gauges, face limitations including large size, high costs, and reduced dynamic resolution, making them unsuitable for precise and dynamic force measurements, especially in precision machining.
Innovation Solution
A tool with a force sensor integrated into the tool shank or holder, allowing direct measurement of tool forces with high precision and dynamics, using a small, compact force sensor that can measure compressive, bending, torsional, and cutting forces, and optionally featuring a preload for measuring negative forces and centripetal forces during tool rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dynamometers are used to measure tool forces, then measurement capability is provided, but large dimensions and high costs occur
Solution Approach 1:
The measuring system is segmented into a compact force sensor integrated directly into the tool shank, separating the measurement function from the large dynamometer structure. This allows precise force measurement without requiring a bulky external measuring device.
Solution Approach 2:
The force sensor is nested within the tool shank structure itself, with the sensor integrated into the existing tool geometry. This eliminates the need for separate external measuring devices and reduces overall system volume while maintaining measurement capability.
2Measurement precision
If strain gauges are used to measure tool forces, then measurement is possible, but flexibility requirements reduce dynamic resolution
Solution Approach 1:
The patent replaces strain gauge technology with a force sensor that uses a different measurement principle, eliminating the need for mechanical flexibility in the tool structure. This substitution maintains measurement precision while removing the complexity and limitations of strain gauge systems.
3Measurement precision
If torque wrench is used to determine clamping force, then clamping force estimation is possible, but friction coefficients cause deviation from actual values
Solution Approach 1:
A force sensor is introduced as an intermediary element between the tool shank and tool holder, directly measuring the clamping force at the interface. This eliminates the need to calculate clamping force through torque and friction coefficient relationships, providing direct and reliable measurement.
4Measurement precision
If measuring plate is used for force measurement, then force measurement capability is provided, but additional mass reduces dynamic properties
Solution Approach 1:
The measuring function is extracted from a separate measuring plate and integrated directly into the tool shank structure. This eliminates the additional mass of a separate measuring plate while maintaining force measurement capability, thereby preserving dynamic properties.
Solution Approach 2:
The force sensor and tool shank are merged into a single integrated structure, eliminating the need for a separate measuring plate. This combination reduces total mass and maintains dynamic response characteristics while providing accurate force measurement.
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 precise and dynamic measurement of tool forces, reducing false alarms and improving tool monitoring by allowing real-time signal analysis, enhancing the detection of tool wear and breakage, and optimizing machining processes with high sensitivity and mechanical stability.
Implementation Method 1
a force sensor arranged in a recess on the tool shank; and during operation of the tool, the force sensor measures a tool force acting from the tool shank onto the tool holder
Data Source
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AI summary
According to the invention, a tool (10) comprises a tool shaft (11), which is received in a tool receptacle (21) of a tool holder (20); the tool (10) also comprises a force sensor (30), which is arranged in a recess (12) on the tool shaft (11); and, during operation of the tool (10), the force sensor (30) measures a tool force acting from the tool shaft (11) on the tool holder (20). The invention also relates to a method for measuring a tool force, with a tool (10), which comprises a tool shaft (11) which is received in a tool receptacle (21) of a tool holder (20); the tool (10) also comprises a force sensor (30); the method comprises the following steps: arranging a force sensor (30) between the tool shaft (11) of the tool (10) and the tool receptacle (21) of the tool holder (20); and clamping the force sensor (30) with the aid of a clamping device of the tool receptacle (21); during operation of the tool (10), the force sensor (30) measures the tool force acting from the tool shaft (11) on the tool holder (20).