Circular Blade Current Monitoring for Sharpening Timing

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Solution Overview

Problem

Conventional disc cutting machines lack precise monitoring of the circular knife's condition, leading to inefficient sharpening schedules, resulting in unclean cuts, increased wear, and unnecessary downtime due to user-dependent sharpening frequencies.

Innovation Solution

Incorporating a knife monitoring device with a current measuring system to track the knife motor current and its time course, allowing for the determination of cutting characteristics such as sharpness, contamination, and wear, enabling automatic detection and optimization of sharpening needs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the user manually determines when to resharpen the blade based on experience, then the operation flexibility is maintained, but the cutting precision deteriorates due to inaccurate timing

Engineering Contradiction:
Improvemanual operation flexibilityVSAvoidcutting precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent replaces manual user judgment with an automated monitoring system that uses electrical current measurement to detect blade wear. The current measuring device continuously monitors the blade motor current, and the control unit automatically determines when sharpening is needed based on current thresholds, eliminating reliance on user experience while maintaining operational simplicity.

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

Solution Approach 2:

The blade monitoring system enables the slicing machine to self-diagnose blade condition and self-determine maintenance timing. The system automatically tracks blade usage through current monitoring and provides alerts when sharpening is required, allowing the machine to manage its own maintenance schedule without external intervention.

Inventive Principle:
Principle #25Self-service

2Manufacturing precision

If the blade is resharpened frequently to maintain cutting quality, then the cutting precision is improved, but the productivity deteriorates due to increased downtime

Engineering Contradiction:
Improvecutting qualityVSAvoidproduction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The system implements continuous feedback through current monitoring to track blade wear in real-time. By measuring the blade motor current and comparing it against predefined thresholds, the system provides accurate feedback on blade condition, enabling sharpening to occur only when necessary rather than on a fixed schedule, thus optimizing both quality and productivity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The monitoring system detects blade wear trends and provides advance warning before cutting quality deteriorates. This preliminary detection allows operators to schedule sharpening at convenient times rather than reacting to quality degradation, minimizing production disruptions while maintaining consistent cut quality.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If the blade is resharpened infrequently to maximize productivity, then the production efficiency is improved, but the manufacturing precision deteriorates due to blade wear

Engineering Contradiction:
Improveproduction efficiencyVSAvoidcutting quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The automated current monitoring system replaces manual inspection and provides objective, continuous measurement of blade wear through electrical parameters. This substitution enables accurate tracking of blade degradation without interrupting production, allowing the blade to be used to its full service life while maintaining quality standards.

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

4Device complexity

If a simple revolution counter is used to monitor blade usage, then the device complexity is minimized, but the measurement precision deteriorates because it cannot account for varying load conditions

Engineering Contradiction:
Improvemonitoring system simplicityVSAvoidblade wear detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The system changes the monitoring parameter from mechanical revolution count to electrical current measurement. By measuring the blade motor current, the system captures information about actual blade load and wear conditions, providing precise wear detection while maintaining relatively simple device architecture through the use of standard current sensing components.

Inventive Principle:
Principle #35Parameter changes

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 approach ensures precise monitoring of the circular knife's condition, optimizing service life, reducing unnecessary downtime, and improving cutting efficiency by automatically triggering sharpening processes when needed.

Implementation Method 1

the blade monitoring device has a current measuring device for measuring the blade motor current

Methodology Applied
Scientific EffectElectrical current measurement: Ohmmeter

Implementation Method 2

a rotating circular blade driven by an electric blade motor

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 3

attach a grinding device, particularly one with a grinding wheel, to the disc cutting machine

Methodology Applied
Scientific EffectAbrasion: Abrasion

Data Source

PatentEP4011577B1Slicer with blade monitoring device and grinding device
Publication Date: 2024.06.05 BIZERBA GMBH & CO KG
  • EP4011577B1 patent drawingFigure 1
  • EP4011577B1 patent drawingFigure 1a
  • EP4011577B1 patent drawingFigure 2a~2d

AI summary

An electrically operated disc cutting machine for cutting discs from strand-like material, comprising a cutting device with a rotating circular blade driven by an electric blade motor, and a blade monitoring device for monitoring the condition of the circular blade, is characterized in that it has a current measuring device for measuring the blade motor current. In a method for monitoring the disc cutting machine according to the invention, the blade motor current and its temporal profile are recorded as measurement data for input into the blade monitoring device, and operation of the disc cutting machine in a blade sharpening program is detected.