Laser Machining Condition Control for Plasma-Reduced Cutting

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Solution Overview

Problem

Laser beam cutting machining often results in the generation of plasma, leading to rough surfaces and adhesion of dross due to the close proximity of the nozzle and workpiece, which complicates setting optimal machining conditions.

Innovation Solution

A machining condition adjustment device that utilizes a high-flow speed assist gas to reduce plasma generation by positioning the workpiece at a specific location where the assist gas flow speed is maximized, and employs machine learning to adjust laser beam machining conditions, such as the gap between the nozzle and workpiece, to optimize cutting quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the nozzle and workpiece are positioned close to each other for high-speed cutting, then cutting speed is improved, but plasma generation increases causing rough surfaces and dross adhesion

Engineering Contradiction:
Improvecutting speedVSAvoidsurface quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent changes the parameter of assist gas flow velocity by positioning the workpiece at the Mach disk location where flow velocity is maximized. This velocity optimization reduces plasma generation while maintaining high-speed cutting capability, resolving the contradiction between productivity and surface quality

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a new dimensional consideration by focusing on the axial flow velocity distribution of assist gas rather than just the radial distance between nozzle and workpiece. By identifying the Mach disk position along the gas flow axis, the patent finds an optimal positioning that simultaneously achieves high cutting speed and low plasma generation

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Stress or pressure

If the nozzle and workpiece are positioned close to each other, then pressure on the workpiece is maximized, but plasma generation increases causing rough surfaces and dross adhesion

Engineering Contradiction:
Improvegas pressure on workpieceVSAvoidsurface quality
Core Design Contradiction:
Stress or pressureVSManufacturing precision

Solution Approach 1:

The patent shifts from optimizing pressure alone to optimizing flow velocity by positioning at the Mach disk. This parameter change reveals that maximum flow velocity occurs at a different position than maximum pressure, and this velocity-based optimization reduces plasma generation while maintaining effective cutting pressure

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If machine learning is used to dynamically adjust machining conditions, then cutting quality is improved, but device complexity increases

Engineering Contradiction:
Improvecutting qualityVSAvoidcontrol system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements feedback control by using machine learning to process detection results in real-time and dynamically adjust machining conditions. This closed-loop system continuously optimizes cutting quality by adapting to varying workpiece conditions, material properties, and plasma generation levels

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The machine learning model enables the system to self-optimize by automatically learning the relationship between machining parameters and plasma generation from historical data. The system performs self-adjustment without requiring external intervention, reducing the need for manual tuning and expert knowledge

Inventive Principle:
Principle #25Self-service

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 solution effectively reduces plasma generation and improves cutting quality by dynamically adjusting machining conditions based on real-time data and machine learning algorithms, accommodating variations in material and plate thickness.

Implementation Method 1

a shock wave is generated from a mouth of the nozzle 5 so as to form a wall, which re-converges the assist gas 6 so as to maximize a flow speed of the assist gas 6 at position (3)

Methodology Applied
Scientific EffectShock wave: Shock Wave

Data Source

PatentUS11958135B2Machining condition adjustment device and machine learning device
Publication Date: 2024.04.16 FANUC LTD
  • US11958135B2 patent drawing
  • US11958135B2 patent drawing
  • US11958135B2 patent drawing

AI summary

A machining condition adjustment device adjusts laser beam machining conditions for a laser beam machining device to carry out laser beam machining of a workpiece, produces each of state variables including machining condition data, workpiece data, and plasma generation amount data and determination data including plasma generation amount determination data, and learns adjustment action for the laser beam machining conditions with respect to an amount of plasma generated in the laser beam machining of the workpiece under prescribed laser beam machining conditions, with use of the produced state variables and the produced determination data.