Laser Cutting Head Motion for Thick-Plate Corner Overburn Control

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Solution Overview

Problem

Existing laser processing methods for thick workpieces face issues with overheating and meltdown at corner portions during thermal cutting, leading to overburning and concave portions in the cutting surface, especially when resuming cutting after interrupting the loop-like processing path.

Innovation Solution

The method involves moving the processing head along the cutting locus without deceleration, stopping the laser beam at the corner, and resuming cutting with a pulsed beam to maintain normal speed, thereby preventing overheating and meltdown.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If thermal cutting processing is interrupted in a loop-like processing path and then resumed after the workpiece reaches the vicinity of the edge portion again, then the processing can be completed, but heat accumulates in the vicinity of the already cut portion causing overburning and concave portions in the cutting surface

Engineering Contradiction:
Improveprocessing completionVSAvoidcutting surface quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by forming a loop-like processing path that proactively redirects the laser beam away from the corner portion before heat accumulation can occur. The processing path is designed to move laterally to a safe distance from the corner, ensuring that when processing resumes, the laser does not immediately re-irradiate the same area, thus preventing overburning and maintaining cutting surface quality.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If thermal cutting processing is resumed after interruption at the corner portion, then processing continues, but meltdown occurs on the lower surface of the edge portion

Engineering Contradiction:
Improveprocessing continuityVSAvoidedge portion integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The loop-like processing path performs preliminary action by strategically routing the laser beam to move laterally away from the corner portion before heat buildup can cause meltdown. This pre-planned path ensures that when processing resumes, the laser irradiation starts from a safe distance, preventing thermal damage to the lower surface of the edge portion while maintaining processing continuity.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If the laser beam is continuously emitted while moving the processing head along the cutting locus, then cutting efficiency is maintained, but heat accumulates at corner portions causing overburning and concave formations

Engineering Contradiction:
Improvecutting efficiencyVSAvoidcutting surface uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies periodic action by implementing a loop-like processing path that periodically redirects the laser beam away from corner portions. This creates a rhythmic pattern of irradiation and non-irradiation zones, allowing heat to dissipate from previously processed areas before the laser returns, thus preventing overburning and maintaining cutting surface uniformity while preserving overall cutting efficiency.

Inventive Principle:
Principle #19Periodic 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 suppresses instability and overheating at corner portions, reducing overburning and concave formations, and maintains cutting quality by preventing excessive heat accumulation.

Implementation Method 1

a laser processing machine main body 50B that irradiates a workpiece W with a laser beam LB

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 2

thermal cutting processing of laser processing machines

Methodology Applied
Scientific EffectThermal melting: Melting

Data Source

PatentEP4400250B1Laser processing method and laser processing machine
Publication Date: 2025.11.26 AMADA CO LTD
  • EP4400250B1 patent drawingFigure 1
  • EP4400250B1 patent drawingFigure 2
  • EP4400250B1 patent drawingFigure 3~4

AI summary

A processing head 35 is moved to a corner portion A along a first side L1 without decelerating while emitting a laser beam; emission of the laser beam is stopped after the processing head 35 which is moving reaches the corner portion A; the processing head 35 is moved from the corner portion A to a first predetermined position D separated by a first predetermined distance D1 along a second side L2 while emitting the laser beam intermittently, and emission of the laser beam is stopped when the processing head reaches the first predetermined position D; the processing head 35 is accelerated from a position E, which is on an extension line of the second side L2 and before the corner portion A, toward the corner portion A; and emission of the laser beam is started when the processing head 35 which is accelerating reaches the corner portion A, and then the processing head 35 is moved along the second side L2.