Pre-Stressed Piezo Sensor Cutting Tool for Reliable Force Sensing
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Solution Overview
Problem
Existing sensorized cutting tools using piezo sensors are expensive, complex, and less reliable, leading to reduced accuracy and increased maintenance costs due to sensor wear and breakage, which complicates their integration into cutting tools.
Innovation Solution
A cutting tool design incorporating an elastically deformable piezo sensor with a pre-stressed initial state, secured by a sensor retaining structure, allows for cost-effective and reliable force measurement by deforming the sensor in response to cutting forces, while maintaining tool accuracy and simplicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a piezo sensor is integrated into a cutting tool to measure cutting forces, then measurement capability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The piezo sensor is integrated directly into the tool body structure, merging the measurement function with the structural components. The sensor becomes part of the tool's load-bearing structure rather than a separate add-on component, reducing overall device complexity while maintaining measurement capability.
Solution Approach 2:
The tool body structure serves multiple functions: it provides mechanical support for cutting operations and simultaneously houses the piezo sensor for force measurement. This multi-functionality eliminates the need for separate measurement devices, reducing complexity and manufacturing cost.
2Reliability
If a rigid piezo sensor is used to withstand cutting forces, then measurement reliability is improved, but manufacturing cost increases due to high geometric tolerances
Solution Approach 1:
The design transitions from requiring rigid sensors with tight geometric tolerances to using elastic sensors that can accommodate larger tolerances. By changing the mechanical properties parameter (from rigid to elastic), the manufacturing requirements are relaxed while maintaining reliability through the sensor's ability to return to its initial state after deformation.
Solution Approach 2:
An elastic piezo sensor is used instead of a rigid crystalline sensor. The elastic material can deform under cutting forces and return to its original state, providing reliability without requiring high geometric tolerances. This flexibility allows for easier manufacturing and assembly.
3Measurement precision
If the piezo sensor is pre-stressed to an initial state, then measurement accuracy in the preferred range is improved, but device complexity increases
Solution Approach 1:
The piezo sensor is pre-stressed during assembly to an initial state that corresponds to a desired position on its characteristic curve. This preliminary action ensures that subsequent cutting forces produce measurements within the preferred linear range, improving measurement accuracy without requiring complex real-time adjustments.
Solution Approach 2:
The sensor's operating point is shifted by applying a static pre-stress, changing the parameter range over which measurements are taken. This allows the sensor to operate in its most linear and accurate range during actual cutting operations, improving measurement precision.
4Measurement precision
If expensive rigid piezo sensors are used, then measurement capability is improved, but reliability decreases due to sensor wear and breakage
Solution Approach 1:
An elastic piezo sensor is used instead of a rigid crystalline sensor. The elastic material can deform under cutting forces and return to its original state, providing reliability without requiring high geometric tolerances. This flexibility allows for easier manufacturing and assembly.
Solution Approach 2:
The elastic sensor material inherently cushions against excessive forces by deforming, preventing breakage. This beforehand cushioning through elastic deformation protects the sensor from damage during abnormal cutting conditions, extending sensor lifespan and improving reliability.
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 provides a resilient and accurate cutting tool with reduced manufacturing complexity and lower costs, enabling effective force detection within a preferred range without breaking or requiring high geometric tolerances, thus improving tool reliability and reducing maintenance.
Implementation Method 1
A type of sensor that is commonly used in various fields, albeit less in cutting tools, are so called piezo sensors. This type of sensor is based on the piezo electric effect, meaning that an electric charge accumulates in certain solid materials in response to an applied mechanical stress.
Data Source
AI summary
A cutting tool includes a tool body having at least one seat for receiving a cartridge or a cutting insert. The seat includes at least one support surface. The cutting tool body includes a sensor retaining structure adjoining the support surface and a piezo sensor arranged in the sensor retaining structure. The cutting tool has a clamping device for securing the cartridge or cutting insert. The piezo sensor is an elastically deformable piezo sensor, which has a central longitudinal axis and a direction of sensitivity perpendicular to the central longitudinal axis. The piezo sensor has a measuring section, along which the central longitudinal axis is substantially parallel to the support surface. The piezo sensor is elastically deformed in the sensor retaining structure to a pre-stressed initial state and deformable to a plurality of further stressed measuring states.