Machine Tool Stator Sensor for Cutting Edge Load Detection

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Solution Overview

Problem

Existing machine tool systems face challenges in accurately and economically monitoring cutting edge wear, leading to potential tool breakage and processing inaccuracies due to the complexity and cost of separate adapters and evaluation devices, as well as increased bearing loads and limited tool holder versatility.

Innovation Solution

Integration of an individual cutting edge sensor within the stator unit of a motor-driven machine tool, eliminating the need for additional adapters and evaluation devices, allowing direct force measurement on cutting edges, and transmitting data through cables for reduced interference and increased accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a separate tool adapter with sensors is used to monitor cutting edge wear, then measurement precision is improved, but device complexity increases significantly

Engineering Contradiction:
Improvecutting edge wear detection accuracyVSAvoidsystem structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The sensor system is merged with the machine tool's existing stator unit rather than using a separate tool adapter. The cutting edge wear sensor is integrated into the stator structure, combining the monitoring function with the existing machine components, thereby reducing overall system complexity while maintaining measurement capability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The stator unit is given multiple functions: it serves both as a structural component of the machine tool and as the mounting platform for the cutting edge wear sensor. This multi-functionality eliminates the need for dedicated separate monitoring devices, reducing device complexity

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

2Measurement precision

If additional separate adapters and evaluation devices are integrated into each tool holder, then measurement precision is improved, but manufacturing cost increases

Engineering Contradiction:
Improvecutting edge wear detection accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The sensor and evaluation functions are merged into the machine tool's existing control system rather than being distributed across multiple tool holders. This consolidation reduces the total number of sensors and evaluation units needed, thereby reducing manufacturing costs

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

A single sensor system serves all cutting edges and tools, providing universal monitoring capability. This eliminates the need for expensive individual sensor integration in each tool holder, significantly reducing overall manufacturing costs

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

3Reliability

If a tool adapter is used to monitor cutting edges, then reliability of tool condition monitoring is improved, but bearing loads increase due to increased effective length

Engineering Contradiction:
Improvetool condition monitoring reliabilityVSAvoidbearing loads
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The sensor system is extracted from the tool holder and relocated to the stator unit. This removes the additional length and leverage arm that would otherwise be introduced by a tool adapter, thereby reducing bearing loads while maintaining the reliability of tool condition monitoring

Inventive Principle:
Principle #2Taking out (Extraction)

4Ease of operation

If wireless transmission of sensor data is used, then ease of operation is improved, but susceptibility to interference increases

Engineering Contradiction:
Improvedata transmission convenienceVSAvoidinterference susceptibility
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

A wired connection serves as an intermediary between the sensor and the control system, providing a stable and interference-resistant data transmission path. This physical connection acts as a shield against electromagnetic interference common in industrial environments, unlike wireless transmission

Inventive Principle:
Principle #24Intermediary (Mediator)

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 enables early and precise detection of cutting edge wear, reducing economic and structural burdens, improving machining accuracy, and preventing tool breakage by integrating sensors directly into the machine tool unit, thus enhancing safety and processing quality.

Implementation Method 1

changes in distance or position resulting from elastic displacements or deformations of components in the force transmission path caused by the cutting edge load

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3922403A1Machine tool unit with a tool sensor and method for detecting the cutting load of a too
Publication Date: 2021.12.15 FRANZ KESSLER GMBH
  • EP3922403A1 patent drawingFigure 1~2
  • EP3922403A1 patent drawingFigure 3~4
  • EP3922403A1 patent drawingFigure 5~6

AI summary

A method for detecting cutting load and a motor-driven machine tool unit (103), such as a multi-axis rotary head or a motor spindle (103), with a stator unit (110) and a rotor unit (105) rotatable about at least one axis of rotation (D), is described, wherein the rotor unit (3, 105) comprises at least one tool holder unit (108) for receiving a tool, wherein the tool holder unit (108) in particular comprises a tool clamping device (101) adjustable in the longitudinal direction of the axis of rotation (D) and subjected to a clamping force for fixing and clamping a detachably fixable tool shank of the tool (50), wherein a tool head of the tool comprises at least one cutting edge, preferably at least two/four cutting edges, wherein at least one tool sensor is provided for detecting the load on the tool.wherein the tool sensor is designed as a single-edge sensor (104) for detecting the cutting load of the individual cutting edge, it is proposed, whereby the prior art is to be improved at least partially. This is achieved according to the invention in particular by the fact that the stator unit (110) comprises at least the single-edge sensor (104).