Tool Holder Slip Detection Using Periodic Process Signals

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

During machining of difficult-to-machine materials, axial and rotational slips in tool-tool holder connections lead to tool pull-out, resulting in quality loss and potential tool breakage, with existing solutions either enhancing friction or using additional locking mechanisms, both of which are costly and complicate predictive modeling.

Innovation Solution

A method to detect and prevent rotational slip by analyzing periodic process signals, such as spindle current, to identify changes in phase and period length, allowing for real-time compensation and prevention of tool pull-out without additional design or locking measures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional locking mechanisms or form-locking elements are added to prevent tool pullout, then tool holder reliability improves, but device complexity and manufacturing costs increase

Engineering Contradiction:
Improvetool holder connection reliabilityVSAvoidtool holder structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical locking mechanisms with a sensor-based detection system that monitors tool position and provides feedback to the control unit, enabling electronic compensation instead of mechanical reinforcement

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements a feedback loop where sensors detect tool position deviations and transmit signals to the control unit, which then adjusts the drive system to compensate for the deviation, creating a closed-loop control system

Inventive Principle:
Principle #23Feedback

2Reliability

If laser-induced roughening or surface treatment is applied to increase frictional engagement, then tool holder reliability improves, but manufacturing costs and processing time increase

Engineering Contradiction:
Improvefrictional engagement reliabilityVSAvoidtool manufacturing simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces physical surface modifications with an electronic monitoring and control system that detects and compensates for slippage through sensor feedback, avoiding additional manufacturing steps

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If sensors and additional measurement devices are added to detect tool position, then measurement precision improves, but device complexity and costs increase

Engineering Contradiction:
Improvetool position detection accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent utilizes existing machine tool sensors and control systems to perform the detection function, allowing the system to monitor its own state without adding external measurement devices

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent employs multi-functional sensors that serve both as position detectors and as triggers for the compensation mechanism, reducing the need for separate dedicated components

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

Data Source

PatentEP4393621A1Method and device for determining a wheel slip of a tool, which is frictionally engaged in a tool holder
Publication Date: 2024.07.03 HAIMER
  • EP4393621A1 patent drawingFigure 1a~2
  • EP4393621A1 patent drawingFigure 3
  • EP4393621A1 patent drawing

AI summary

The invention relates to a method and a device for determining the rotational slip of a tool 6 frictionally held in a tool holder 4. By evaluating a phase and/or a period length of a periodic process signal of the tool 6, a rotational slip of a tool 6 frictionally held in the tool holder 4 is determined.