Workpiece Part Extraction Using Cyclic Clamping Relief

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Solution Overview

Problem

Automated laser cutting machines face challenges in reliably removing workpiece parts from residual skeletons due to high forces that can damage extraction devices, particularly during intermediate removal attempts, where the 'sandwich removal' method risks bending lifting elements.

Innovation Solution

The method involves reducing and then restoring the clamping force on workpiece parts by alternately building and releasing mechanical stresses between the ejection and counter-holding devices, allowing for partial or complete dissolution of the 'sandwich' without triggering damaging movements, and using sensor devices to ensure complete separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the workpiece part is clamped between ejection element and counter-holding element for removal, then the workpiece part can be securely gripped and moved, but the forces acting on the extraction devices become too great and can damage the devices (e.g., bending lifting pins)

Engineering Contradiction:
Improvesecure gripping of workpiece partVSAvoidstrength of ejection device components
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies dynamics by making the clamping force adjustable rather than static. The control device dynamically adapts the clamping force of the ejection element and counter-holding element based on the detected separation status. When separation is detected, the clamping force is reduced or released to prevent damage; when separation is not detected, the clamping force is restored to maintain secure gripping. This dynamic adjustment resolves the contradiction between secure gripping and preventing device damage.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of clamping force from a constant value to a variable parameter. The control device modifies the clamping force parameter based on feedback from the sensor device. The clamping force is increased when workpiece parts need to be securely held during removal, and decreased or released when separation is confirmed, thereby preventing excessive forces that could damage the ejection device components while maintaining reliable gripping when needed.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If release strategy with repeated movements is used to free caught workpiece parts, then workpiece parts can be freed from jammed positions, but the forces become too great and can damage the removal devices

Engineering Contradiction:
Improveability to free caught workpiece partsVSAvoidstrength of removal device components
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent applies dynamics by making the clamping force adjustable rather than static. The control device dynamically adapts the clamping force of the ejection element and counter-holding element based on the detected separation status. When separation is detected, the clamping force is reduced or released to prevent damage; when separation is not detected, the clamping force is restored to maintain secure gripping. This dynamic adjustment resolves the contradiction between secure gripping and preventing device damage.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of clamping force from a constant value to a variable parameter. The control device modifies the clamping force parameter based on feedback from the sensor device. The clamping force is increased when workpiece parts need to be securely held during removal, and decreased or released when separation is confirmed, thereby preventing excessive forces that could damage the ejection device components while maintaining reliable gripping when needed.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If complete clamping force is maintained during repeated removal attempts, then workpiece parts remain securely held, but the mechanical stresses become too great and can damage the ejection device components

Engineering Contradiction:
Improvesecure holding of workpiece partVSAvoidmechanical stress on ejection device
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies dynamics by making the clamping force adjustable rather than static. The control device dynamically adapts the clamping force of the ejection element and counter-holding element based on the detected separation status. When separation is detected, the clamping force is reduced or released to prevent damage; when separation is not detected, the clamping force is restored to maintain secure gripping. This dynamic adjustment resolves the contradiction between secure gripping and preventing device damage.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of clamping force from a constant value to a variable parameter. The control device modifies the clamping force parameter based on feedback from the sensor device. The clamping force is increased when workpiece parts need to be securely held during removal, and decreased or released when separation is confirmed, thereby preventing excessive forces that could damage the ejection device components while maintaining reliable gripping when needed.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3852984B1Method and device for removing a workpiece part from the remainder of the workpiece
Publication Date: 2022.10.19 TRUMPF WERKZEUGMASCHINEN GMBH & CO KG
  • EP3852984B1 patent drawingFigure 1
  • EP3852984B1 patent drawingFigure 2a~2d
  • EP3852984B1 patent drawingFigure 2e~2g

AI summary

The invention relates to a method for removing a workpiece part (20) from the remainder (2a) of the workpiece mounted in a bearing plane (E), comprising: moving the workpiece part (20), which is clamped between at least one ejector element (52) of an ejection device (32) and at least one counter-holding element (49b, c, 47) of a counter-holding device (34), in a removal direction (Z), and checking whether the workpiece part (20) has been fully separated from the remainder (2a) of the workpiece on moving in the removal direction (Z). The method is characterized by reducing or completely ceasing the clamping of the workpiece part (20) and subsequently resuming the clamping of the workpiece part (20) if the check determines that the workpiece part (20) was not fully separated from the remainder (2a) of the workpiece. The invention also relates to an associated device.