Workpiece Removal Using Structure-Borne Sound Separation Detection

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Solution Overview

Problem

Existing methods struggle to reliably remove workpiece parts from plate-shaped workpieces, particularly when coated with oil or foil, due to difficulties in resistance measurements, especially for non-conductive materials.

Innovation Solution

A method utilizing structure-borne sound signals to detect the separation of workpiece parts from the remaining workpiece, employing a sensor device with a pulse generator and vibration sensor to evaluate vibrations, allowing non-destructive detection of complete separation and potential malfunctions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If resistance measurement is used to detect workpiece separation, then separation detection is achieved, but it becomes difficult or impossible for coated or non-conductive workpieces

Engineering Contradiction:
Improveseparation detection reliabilityVSAvoidapplicability to coated/non-conductive workpieces
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the electrical resistance measurement system with an acoustic vibration detection system. A vibration sensor detects structure-borne sound signals generated during the separation process, eliminating the need for electrical contact with the workpiece. This allows reliable separation detection for coated and non-conductive workpieces that cannot be measured by electrical resistance methods.

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

Solution Approach 2:

The patent introduces structure-borne sound signals as an intermediary medium to detect workpiece separation. Instead of directly measuring electrical resistance between contact elements, the system uses acoustic vibrations transmitted through the workpiece and remaining workpiece to indirectly detect separation status, enabling universal application across different material types.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If electrical contact elements are used for resistance measurement, then separation detection is possible, but the method fails for oiled or foil-covered workpieces

Engineering Contradiction:
Improveseparation detection accuracyVSAvoidinterference from oil film or foil coating
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent substitutes electrical measurement with acoustic measurement. The vibration sensor detects mechanical vibrations and structure-borne sound signals that propagate through the workpiece during separation, bypassing the interfering oil film or foil coating that blocks electrical contact. This enables accurate separation detection regardless of surface coatings.

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

3Extent of automation

If a gripping device performs lifting movement for workpiece removal, then automated removal is achieved, but unreliable separation detection compromises process safety

Engineering Contradiction:
Improveautomated workpiece removalVSAvoidprocess safety during removal
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the vibration sensor continuously monitors separation status during the automated lifting process. The control system receives real-time vibration signals and adjusts the gripping device operation accordingly, enabling safe automated removal by confirming complete separation before finishing the removal cycle.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The vibration-based separation detection is performed before the gripping device completes the removal operation. This preliminary detection confirms that the workpiece part is fully separated from the remaining workpiece, preventing dangerous situations where entangled or partially attached workpieces could cause damage during removal.

Inventive Principle:
Principle #10Preliminary action

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

Ensures high process reliability by accurately detecting complete separation and potential issues such as entanglement or miscuts, enabling safe and automated removal of workpiece parts from various materials, including unoiled, oiled, or coated workpieces.

Implementation Method 1

a sensor device is activated which detects the separation of the workpiece part from the remaining workpiece by means of structure-borne sound

Methodology Applied
Scientific EffectStructure-borne sound: Sound

Implementation Method 2

a vibration sensor for detecting the structure-borne sound, by means of which a proportion of the structure-borne sound transmitted across the cutting gap to the remaining workpiece or workpiece part is determined

Methodology Applied
Scientific EffectVibration detection: Vibration

Data Source

PatentEP3928888B1Method for removing a workpiece part in a processing machine, data processing program and processing machine
Publication Date: 2026.03.18 TRUMPF WERKZEUGMASCHINEN GMBH & CO KG
  • EP3928888B1 patent drawingFigure 1
  • EP3928888B1 patent drawingFigure 2
  • EP3928888B1 patent drawingFigure 3~4

AI summary

The invention relates to a method for removing a workpiece part (14) from a remaining workpiece (17) formed by machining a plate-shaped workpiece (12) resting on a workpiece support (15), wherein the plate-shaped workpiece (12) is fixed for machining by means of a clamping device (20, 21, 22, 23) and is movable along at least one X or Y direction in a support plane of the workpiece support (15), wherein before or after separating the workpiece part (14) from the plate-shaped workpiece (12), a gripping device (52) is positioned towards the workpiece part (14) in a removal position, wherein at least one gripping element or suction element (61) of the gripping device (52) engages the workpiece part (14), and wherein a sensor device (71) is activated before the gripping device (52) is controlled to remove the workpiece part (14) from the remaining workpiece (17).by which the separation of at least one workpiece part (14) from the remaining workpiece (17) is detected by means of structure-borne sound vibrations.