Laser Cutting Clamp Release to Prevent Plate Warping

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Solution Overview

Problem

Heat input during the cutting process in processing machines, such as laser cutting machines, causes tension in plate-shaped workpieces, leading to curling and cutting breaks, which result in incomplete separation of workpiece parts and reduced dimensional accuracy.

Innovation Solution

The method involves interrupting the cutting process with relaxation steps, where clamping devices are briefly released and then re-clamped to alleviate heat-induced tension, with the number and timing of these steps controlled based on workpiece size, material thickness, and laser power to maintain dimensional accuracy and prevent cutting breaks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If continuous cutting process is used to maintain high productivity, then production efficiency is improved, but heat-induced tension causes warping and cutting breaks that reduce manufacturing precision

Engineering Contradiction:
Improveproduction efficiencyVSAvoiddimensional accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The cutting process is interrupted at regular intervals to perform stress-relieving steps where clamping devices are released and re-clamped. This periodic interruption allows the workpiece to relax heat-induced tension while maintaining overall process efficiency through automated control of the interrupt/continue sequence.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

Stress-relieving steps are performed in advance before cutting breaks occur. By proactively releasing and re-clamping the workpiece during the cutting process, the method prevents warping and cutting breaks before they happen, ensuring dimensional accuracy is maintained throughout production.

Inventive Principle:
Principle #10Preliminary action

2Stability of the object's composition

If clamping devices are continuously engaged to prevent workpiece movement, then positioning stability is improved, but heat-induced tension causes warping that leads to cutting breaks

Engineering Contradiction:
Improvepositioning stabilityVSAvoidprocess reliability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

Clamping devices are periodically released and re-clamped during the cutting process. This periodic action allows the workpiece to relax accumulated heat-induced tension while maintaining positioning stability through automated re-clamping, preventing cutting breaks and ensuring process reliability.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The workpiece is proactively stressed-relieved during the cutting process by releasing and re-clamping devices before cutting breaks occur. This preliminary stress relief maintains positioning stability while preventing reliability issues from warping-induced cutting breaks.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If stress-relieving steps are frequently performed to reduce heat-induced tension, then dimensional accuracy is improved, but production time increases reducing productivity

Engineering Contradiction:
Improvedimensional accuracyVSAvoidproduction time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

Stress-relieving steps are performed at optimized intervals during the cutting process. This periodic approach balances dimensional accuracy improvement with productivity maintenance by interrupting the cutting process only when necessary, rather than continuously or too frequently.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

Stress-relieving steps are strategically performed in advance before warping and cutting breaks occur. By proactively managing heat-induced tension at optimal points in the cutting sequence, the method achieves dimensional accuracy improvements without excessive production time penalties.

Inventive Principle:
Principle #10Preliminary action

4Measurement precision

If clamping force is continuously applied to prevent workpiece movement, then positioning accuracy is improved, but heat-induced tension accumulates causing warping

Engineering Contradiction:
Improvepositioning accuracyVSAvoidworkpiece shape
Core Design Contradiction:
Measurement precisionVSShape

Solution Approach 1:

Clamping force is applied periodically rather than continuously. The clamping devices are released and re-clamped at intervals during the cutting process, allowing the workpiece to relax accumulated heat-induced tension while maintaining positioning accuracy through automated re-clamping sequences.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The workpiece is proactively stressed-relieved during cutting by releasing and re-clamping devices before excessive warping occurs. This preliminary stress relief maintains positioning accuracy while preventing harmful changes to the workpiece shape from accumulated heat-induced tension.

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

This approach reduces distortion and cutting breaks, ensuring high dimensional accuracy and process reliability by minimizing the impact of heat-induced tension, allowing for efficient production of workpiece parts with reduced machine productivity loss.

Implementation Method 1

When machining the plate-shaped workpiece to produce the workpiece parts using a process beam, in particular a laser beam, the heat introduced during the cutting process can lead to warping in the plate-shaped workpiece

Methodology Applied
Scientific EffectLaser heating: Laser

Data Source

PatentEP4157574B1Method of producing workpiece parts from a plate-shaped workpiece and data processing program and processing machine for producing the same
Publication Date: 2025.01.15 TRUMPF WERKZEUGMASCHINEN GMBH & CO KG
  • EP4157574B1 patent drawingFigure 1
  • EP4157574B1 patent drawingFigure 2~3
  • EP4157574B1 patent drawingFigure 4

AI summary

The invention relates to a method for producing workpiece parts (14) from a planar workpiece (12) in a machine tool, more particularly a laser machine tool, and to a data processing program and a machine tool for producing said workpiece parts, wherein the planar workpiece (12) is positioned on a workpiece support and is retained with respect to the workpiece support by means of clamping devices (20, 21, 22); wherein a plurality of workpiece parts (14) is cut from the planar workpiece (12) by means of a process beam; and wherein the process beam is moved relative to the workpiece support by means of a machining head and/or the planar workpiece (12) is moved relative to the workpiece support by means of the clamping devices (20, 21, 22). A cutting process for processing the planar workpiece (12) in order to produce the workpiece parts (14) is interrupted at least once by a relaxation step for the planar workpiece (12). In the relaxation step, at least one clamping device (20, 21, 22) is released so that the planar workpiece (12) relaxes. After the planar workpiece (12) has relaxed and before the cutting process is continued, the at least one clamping device (20, 21, 22) is closed.