Laser Cutting Condition Control Using Rearward Temperature Rise

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Solution Overview

Problem

Laser cutting conditions in machines are unstable due to temperature fluctuations at the cut part, making it difficult to maintain high cutting accuracy and speed, especially when cutting a workpiece over an extended period, as conventional methods rely on temperature measurements that are prone to noise and heat accumulation.

Innovation Solution

A cutting condition adjustment apparatus that uses a temperature rise value per predetermined period at an oblique rearward part of the workpiece, which is less susceptible to noise, to accurately assess the heat transfer and adjust the laser cutting conditions, incorporating a machine learning device to learn and adapt the cutting conditions based on observed state variables and determination data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If temperature at the cut part is used for adjusting laser cutting condition, then cutting condition can be adjusted based on real-time feedback, but the adjustment becomes unstable due to noise from kerf width, pressure loss, and assist gas outflow

Engineering Contradiction:

Improvestability of cutting condition adjustmentVSAvoidaccuracy of temperature measurement at cut part

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediary approach by using temperature data from multiple locations (including but not limited to the cut part) and combining it with other process parameters (kerf width, pressure loss, assist gas outflow) to create a more robust feedback signal. This intermediary processing filters out the noise from individual measurements while preserving the essential thermal state information needed for stable cutting condition adjustment.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If laser cutting is continuously performed on a single workpiece for a long period, then productivity increases, but the workpiece temperature rises due to heat accumulation making it difficult to accurately grasp the heat transfer from laser

Engineering Contradiction:

Improvecontinuous cutting capabilityVSAvoidaccuracy of heat transfer measurement

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism that continuously monitors temperature at multiple locations during continuous cutting operations. By tracking temperature evolution over time and comparing it with laser parameters and process conditions, the system can distinguish between heat generated by laser irradiation and heat accumulated from continuous operation. This feedback loop enables accurate heat transfer assessment even during prolonged cutting of single workpieces.

Inventive Principle:

Principle #23Feedback

3Device complexity

If conventional temperature measurement methods are used, then the system is simple to implement, but the cutting condition becomes unstable due to noise from various cutting parameters

Engineering Contradiction:

Improvesimplicity of temperature measurement systemVSAvoidstability of cutting condition

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent merges multiple measurement data sources (temperature from various locations, kerf width measurements, pressure loss data, assist gas flow information) into a unified feedback system. By combining these previously separate measurement streams, the system creates a comprehensive view of the cutting process that filters out individual noise sources while maintaining overall system simplicity through integrated processing.

Inventive Principle:

Principle #5Merging (Combining)

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 allows for stable and accurate adjustment of laser cutting conditions, ensuring high cutting quality and speed by reflecting the true state of the cut part, even with changing environmental temperatures or workpiece heat, thereby improving the overall performance of the laser cutting process.

Implementation Method 1

a laser machine that performs cutting such as cutting of a workpiece with laser light

Methodology Applied

Scientific EffectLaser heating: Laser

Implementation Method 2

the temperature of the workpiece rises with an increase in an amount of heat accumulated in the workpiece

Methodology Applied

Scientific EffectThermal energy transfer: Heating

Data Source

PatentUS11554448B2Machining condition adjustment apparatus and machine learning device

Publication Date: 2023.01.17 FANUC LTD

AI summary

Disclosed is a machine learning device of a cutting condition adjustment apparatus including: a state observation section that observes, as state variables indicating a current state of an environment, cutting condition data indicating a laser cutting condition for a laser cutting and oblique rearward temperature rise data indicating a temperature rise value at an oblique rearward part of a cutting front of a workpiece, a determination data acquisition unit that acquires temperature rise value determination data for determining propriety of the temperature rise value during cutting based on the laser cutting condition for the laser cutting as determination data indicating a propriety determination result of the cutting of the workpiece, and a learning unit that learns the temperature rise value and adjustment of the laser cutting condition for the laser cutting in association with each other using the state variables and the determination data.