Laser Machining Path Control for Variable-Thickness Workpieces

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Solution Overview

Problem

Existing laser machining methods face challenges in maintaining machining quality when the attributes of a workpiece, such as thickness and material, vary along the welding locus, leading to issues like lack of penetration or burn-through.

Innovation Solution

A laser machining method that adjusts the locus velocity and output of the laser based on attribute information of the workpiece, dividing the radiation locus into areas corresponding to varying thickness or attributes to maintain consistent machining quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the laser output and locus velocity are kept constant during machining, then the machining process is simple and fast, but the machining quality deteriorates when workpiece attributes (thickness, material) vary along the welding locus

Engineering Contradiction:
Improvemachining qualityVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by obtaining attribute information about the workpiece (thickness, material composition) before the machining process begins. This pre-acquired information is then used to pre-calculate and set the appropriate laser output and locus velocity for different sections of the workpiece, ensuring optimal machining quality from the start without requiring real-time adjustments during machining.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements dynamics by making the laser output and locus velocity variable rather than constant. Based on the obtained attribute information, the laser output and locus velocity are dynamically adjusted according to the specific attributes at different positions along the welding locus, allowing the machining parameters to adapt to variations in workpiece thickness and material composition.

Inventive Principle:
Principle #15Dynamics

2Strength

If the laser output is increased to ensure penetration in thicker portions, then penetration is improved, but burn-through occurs in thinner portions

Engineering Contradiction:
Improvepenetration depthVSAvoidburn-through
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by setting different laser output levels for different sections of the workpiece based on their specific attributes. Thicker portions receive higher laser output to ensure adequate penetration, while thinner portions receive lower laser output to prevent burn-through. This localized parameter adjustment ensures each area receives the appropriate energy input for its specific thickness and material properties.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements parameter changes by varying the laser output and locus velocity parameters according to the workpiece attributes. The laser output is adjusted as a variable parameter rather than a fixed value, allowing it to be optimized for each specific section's thickness and material composition, thereby achieving both sufficient penetration and prevention of harmful burn-through effects.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If the locus velocity is reduced to improve machining quality in varying thickness areas, then machining quality improves, but productivity decreases

Engineering Contradiction:
Improvemachining qualityVSAvoidmachining speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies dynamics by making the locus velocity variable rather than constant. The locus velocity is adjusted dynamically based on the workpiece attributes at different positions - slower speeds are used in sections with varying thickness or difficult-to-machine materials to ensure quality, while faster speeds are maintained in sections with uniform, easily machinable attributes, thereby optimizing both quality and productivity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements segmentation by dividing the machining path into multiple sections based on workpiece attributes. Each section is assigned an appropriate locus velocity based on its specific characteristics, allowing the overall machining process to maintain high productivity by using faster speeds where possible while ensuring quality in critical sections through slower, more controlled machining.

Inventive Principle:
Principle #1Segmentation

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

The method effectively maintains machining quality by adjusting the laser parameters according to the workpiece attributes, preventing variations in machining quality even when attributes change along the workpiece.

Implementation Method 1

a head (100) making a motion to move along a machining line (200) set on the workpiece (W), using laser, performs laser machining on the workpiece (W)

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 2

performs laser machining on the workpiece (W) by making a radiation locus (P) with the laser

Methodology Applied
Scientific EffectLaser melting: Laser

Data Source

PatentEP3486024B1Laser machining method, controller, and robot system
Publication Date: 2023.09.13 YASKAWA DENKI KK
  • EP3486024B1 patent drawingFigure 1
  • EP3486024B1 patent drawingFigure 2
  • EP3486024B1 patent drawingFigure 3

AI summary

A laser machining method uses a head and a robot. The head is configured to variably make a radiation locus on a workpiece using laser. The robot is configured to cause the head to move. The laser machining method includes obtaining attribute information indicating a distribution of an attribute of the workpiece in a machined area of the workpiece. A shape of the radiation locus is divided into a plurality of divided areas. Based on the attribute information and in each of the plurality of divided areas, at least one of a locus velocity of the laser from the head and an output of the laser from the head is adjusted.