Elastic Piezo Sensor Mounting in Cutting Tools for Force Sensing

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing cutting tools equipped with piezo sensors are expensive, complex, and lack reliability and accuracy due to the use of rigid sensors that wear out quickly and require high geometric tolerances, leading to potential tool failure and increased maintenance costs.

Innovation Solution

A cutting tool design featuring an elastically deformable piezo sensor with a pre-stressed initial state, integrated into a sensor retaining structure that deforms under cutting forces, allowing for the use of a generic and cost-effective sensor, while maintaining accuracy and reliability by registering stress through a plurality of stressed measuring states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If rigid piezo sensors are used in cutting tools, then measurement capability is provided, but the tool becomes expensive and complex

Engineering Contradiction:
Improvecutting force measurementVSAvoidtool structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the mechanical parameters of the sensor from rigid to elastically deformable, allowing the sensor to flex under cutting forces while maintaining measurement capability. This elasticity enables the use of simpler, less expensive sensor designs that can withstand the dynamic loading conditions of cutting operations.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The sensor retaining structure incorporates dynamic elements that allow controlled movement and deformation during cutting operations. The elastically deformable sensor can dynamically respond to varying cutting forces without requiring complex rigid mounting structures, reducing overall device complexity.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If rigid piezo sensors are used in cutting tools, then measurement capability is provided, but reliability decreases due to quick wear out

Engineering Contradiction:
Improvecutting force measurementVSAvoidsensor durability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

Changing the sensor from rigid to elastically deformable allows it to absorb mechanical shocks and stresses during cutting operations. The elastic properties enable the sensor to return to its original shape after deformation, preventing permanent damage and extending service life.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The elastically deformable sensor structure acts as a cushioning element that absorbs peak loads and shock forces before they can damage the sensing elements. This pre-built-in elastic compliance protects the sensor from wear and failure during normal cutting operations.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Manufacturing precision

If high geometric tolerances are applied to the sensor, then positioning accuracy is improved, but manufacturing cost increases

Engineering Contradiction:
Improvesensor positioningVSAvoidsensor installation
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The elastically deformable sensor can accommodate variations in positioning through its inherent flexibility. Instead of requiring precise rigid alignment, the elastic structure naturally adjusts to fit within the retaining structure, significantly easing manufacturing and installation requirements.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The elastic sensor structure functions similarly to a flexible element that can deform to accommodate manufacturing tolerances. This flexibility eliminates the need for high-precision machining and alignment procedures, reducing manufacturing costs and complexity.

Inventive Principle:
Principle #30Flexible shells and thin films

4Adaptability or versatility

If the piezo sensor is made specifically for various tool and insert size combinations, then adaptability is improved, but device complexity increases

Engineering Contradiction:
Improvesensor compatibilityVSAvoidsensor design variety
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The elastically deformable sensor design creates a universal mounting solution that can accommodate various tool and insert sizes. The elastic structure naturally adapts to different geometries without requiring custom-designed sensors for each application, enabling a single sensor type to serve multiple purposes.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The dynamic elastic properties of the sensor allow it to adapt its deformation characteristics based on the specific tool and insert configuration. This dynamic adaptability provides versatility across different applications without requiring multiple specialized sensor designs.

Inventive Principle:
Principle #15Dynamics

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, reliable, and cost-effective cutting tool with improved accuracy and reduced maintenance needs, as the elastically deformable piezo sensor can detect cutting forces without compromising tool performance and extends the tool's lifespan by distributing mechanical stress effectively.

Implementation Method 1

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.

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

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.

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4344808A1Sensorized cutting tool
Publication Date: 2024.04.03 WALTER AG
  • EP4344808A1 patent drawingFigure 1a~1d
  • EP4344808A1 patent drawingFigure 2a~2b
  • EP4344808A1 patent drawingFigure 3a~3c

AI summary

A cutting tool (1) comprising a tool body (2) comprising at least one seat (3) for receiving a cartridge (4) or a cutting insert (5), wherein the seat (3) comprises at least one support surface (6). The cutting tool body (2) comprises a sensor retaining structure (7) adjoining the support surface (7) and a piezo sensor (8) arranged in the sensor retaining structure (7). The cutting tool (1) comprises clamping means (9) for securing the cartridge (4) or cutting insert (5), and the piezo sensor (8) is an elastically deformable piezo sensor (8), which has a central longitudinal axis (24) and a direction of sensitivity perpendicular to the central longitudinal axis (24). The piezo sensor (8) comprises a measuring section (10), along which the central longitudinal axis (24) is substantially parallel to the support surface (6). The piezo sensor (8) is elastically deformed in the sensor retaining structure (7) to a pre-stressed initial state (19) and deformable to a plurality of further stressed measuring states (21).