Machine Tool Drive Frequency Monitoring for Tool Condition Detection

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Solution Overview

Problem

Existing methods for detecting the status of machine tool components are complex and cost-intensive, particularly due to the need for additional sensor installations which can be challenging in limited machine tool spaces.

Innovation Solution

A method that uses the actual and reference drive frequencies of the rotary and positioning drives to determine the tool status, eliminating the need for additional sensors by storing reference drive frequencies in a control unit and comparing them with actual frequencies, allowing for real-time monitoring and reporting of tool conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sensor means are installed to detect the actual state of machine tool components, then detection accuracy is improved, but device complexity and installation difficulty increase

Engineering Contradiction:
Improvedetection accuracyVSAvoidsensor installation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The machine tool's existing drive systems (rotary drive and positioning drive) monitor themselves by detecting their own drive frequencies. The control unit evaluates the actual drive frequency against reference drive frequency to determine tool status, eliminating the need for external sensors to monitor tool conditions.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Physical sensor installations are replaced with an electrical/electronic monitoring approach. The control unit uses electrical signals from the existing drive systems to detect tool status through frequency analysis, substituting mechanical sensor installations with electronic signal processing.

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

2Reliability

If additional sensor means are installed in the machine tool, then tool status monitoring is improved, but installation space requirements and cost increase

Engineering Contradiction:
Improvetool status monitoringVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The existing drive systems serve dual functions: they perform their primary machining functions while simultaneously providing tool status monitoring through their drive frequency signals. The control unit processes these signals to detect tool wear, breakage, or other anomalies without requiring dedicated monitoring hardware.

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

Solution Approach 2:

The drive systems monitor the tool condition as part of their normal operation. The control unit continuously compares actual drive frequency with reference values to detect tool status changes, making the system self-monitoring without additional space-consuming sensors.

Inventive Principle:
Principle #25Self-service

3Device complexity

If reference drive frequencies are stored and compared with actual frequencies, then tool status detection is simplified, but data processing requirements increase

Engineering Contradiction:
Improvedetection method complexityVSAvoidcomputational energy
Core Design Contradiction:
Device complexityVSUse of energy by stationary object

Solution Approach 1:

Instead of analyzing complex multi-parameter tool condition data, the system focuses on a single key parameter: drive frequency. By comparing only the actual drive frequency against reference frequency, the system achieves effective tool status detection with minimal computational effort and energy consumption.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system transforms physical tool condition (wear, breakage) into changes in drive frequency parameters. By monitoring frequency variations rather than directly measuring physical tool properties, the system simplifies detection while maintaining accuracy through the relationship between tool condition and drive system response.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3493005B1Method for detecting at least one tool condition of a tool of a tooling machine for machining workpieces and tooling machine
Publication Date: 2021.04.07 POINT 8 GMBH
  • EP3493005B1 patent drawingFigure 1
  • EP3493005B1 patent drawingFigure 2

AI summary

The invention relates to a method for acquiring at least one tool state of a tool (12) of a machine tool (2) for machining workpieces (10), which comprises at least one rotary drive (6) driving the tool holder (4), at least one positioning drive (8), at least one tool (12), and at least one control unit (14) comprising a storage medium (14), comprising the steps: a. Acquiring or providing tool and/or workpiece data in the storage medium (14) and/or the control unit (16); b. Providing at least one reference drive frequency of the rotary drive (6) and/or the positioning drive (8), to which a reference tool state of the tool (12) is assigned, at least as a function of the tool and/or workpiece data; c. Acquiring at least one actual drive frequency of the rotary drive (6) and/or the positioning drive (8); d.Assigning the actual drive frequency to a reference drive frequency of the rotary drive (6) and/or the positioning drive (8) by the control unit (16) and evaluating and/or interpreting at least the reference drive frequency assigned to the actual drive frequency by the control unit (16).