Rotatable Tool Holder Axial Displacement Detection

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Solution Overview

Problem

Current methods fail to detect axial displacement of cutting tools during machining, leading to tool slip and potential damage to workpieces and machine spindles, as they do not effectively monitor or prevent pull-out events.

Innovation Solution

A method involving a rotatable tool holder with a position sensor to measure axial displacement, transmitting output signals for calculating and determining pull-out, allowing for timely intervention to prevent damage, and a system to compensate for or stop the tool holder rotation when pull-out is detected.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If frictional forces are used to hold the cutting tool in the tool holder, then the tool can be secured during machining, but the tool may be pulled out when axial forces overcome the frictional forces

Engineering Contradiction:

Improvetool holding reliabilityVSAvoidtool pull-out risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A position sensor continuously measures the axial position of the cutting tool relative to the tool holder and provides real-time feedback. When the tool displacement exceeds a predetermined threshold indicating pull-out, the system generates a signal to alert the operator or automatically stop machining, preventing workpiece damage and tool failure.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces purely mechanical friction-based tool holding with a sensor-based detection system. Instead of relying solely on frictional forces to prevent pull-out, an electromagnetic or capacitive position sensor monitors tool position, substituting mechanical reliance with electronic detection and control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If improvements are made to the gripping function of the tool holder to reduce tool slippage risk, then tool holding security is enhanced, but there is still no way to detect actual displacement during machining

Engineering Contradiction:

Improvetool holding securityVSAvoidtool position information

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The position sensor provides continuous feedback on the axial position of the cutting tool, enabling real-time monitoring of tool displacement. This feedback mechanism fills the information gap by continuously reporting tool position status to the control system or operator.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The position sensor acts as an intermediary between the cutting tool and the control system. It measures the physical displacement of the tool and converts it into an electrical signal that can be processed and used for detection and control purposes.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the axial position of the cutting tool is continuously measured during machining, then pull-out can be detected in real-time, but the system complexity increases with additional sensors and signal processing

Engineering Contradiction:

Improvepull-out detection capabilityVSAvoidmonitoring system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The position sensor serves multiple functions: it monitors tool position for pull-out detection, provides feedback for adaptive machining control, and can be used for tool wear compensation. This multi-functionality justifies the added complexity by providing multiple benefits from a single sensor integration.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses the existing machining process infrastructure (tool holder, control system) to support the position monitoring function. The sensor integrates with the existing tool holder design and utilizes the machine's control system for signal processing, minimizing additional complexity.

Inventive Principle:

Principle #25Self-service

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 real-time detection and prevention of tool slip, maintaining machining tolerances and reducing the risk of tool breakage and machine damage by allowing for immediate action when axial displacement exceeds a threshold.

Implementation Method 1

an axial position of the cutting tool in the tool holder is measured by means of a position sensor in the tool holder

Methodology Applied

Scientific EffectPosition sensing:

Data Source

PatentUS10828740B2Method of determining pull-out of a cutting tool and a rotatable tool holder for a cutting tool

Publication Date: 2020.11.10 SANDVIK INTELLECTUAL PROPERTY AB

AI summary

A method of determining pull-out of a cutting tool mounted in a rotatable tool holder includes the steps of rotating the tool holder and thus the cutting tool, machining a work piece with the rotating cutting tool, measuring an axial position of the cutting tool in the tool holder during machining by a position sensor in the tool holder, calculating an axial displacement from an initial position of the cutting tool by the measured axial position, and determining pull-out of the cutting tool when the axial displacement exceeds a threshold value. A rotatable tool holder for a cutting tool, a machine tool system including a rotatable tool holder and use of the tool holder and machine tool system is also provided.