Assist Gas Flow Calculation Using Pressure and Nozzle Gap

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Solution Overview

Problem

Current methods for laser processing lack a specific calculation method to accurately determine the flow rate of assist gas, which is crucial for processing quality, despite the importance of pressure and nozzle geometry, and do not account for the gap value between the nozzle and workpiece.

Innovation Solution

A device and method that calculate the assist gas flow rate using a linear function related to pressure and a polynomial function related to the gap value, allowing for precise determination of the flow rate by measuring pressure and gap distance, with stored coefficients specific to each nozzle type.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the flow rate of assist gas is controlled based on pressure and nozzle opening area only, then the control is simple, but the accuracy of flow rate calculation is insufficient when gap value varies

Engineering Contradiction:
Improveflow rate calculation accuracyVSAvoidcalculation method complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention changes the calculation parameters from simple pressure and opening area to a comprehensive model including pressure, nozzle opening area, and gap value. By introducing the gap value as an additional parameter and using polynomial approximation, the system achieves accurate flow rate calculation across varying gap conditions without requiring complex experimental determination for each scenario.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If a specific calculation formula considering gap value is developed, then the flow rate calculation accuracy improves, but the ease of operation decreases due to complex calculations

Engineering Contradiction:
Improveflow rate calculation accuracyVSAvoidcalculation operation simplicity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The invention performs preliminary actions by pre-calculating and storing polynomial approximation coefficients for different nozzle types and opening areas. This allows the system to quickly determine accurate flow rates during operation by simply substituting measured pressure and gap values into pre-prepared formulas, avoiding complex real-time calculations while maintaining high accuracy.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If the high workability region is determined in advance for each gap value, then the processing quality is improved, but the productivity decreases due to extensive determination requirements

Engineering Contradiction:
Improvelaser processing qualityVSAvoiddetermination process efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention creates a generalized calculation model that copies the essential relationships between pressure, gap value, and flow rate into polynomial approximation formulas. Instead of determining high workability regions through extensive experiments for each gap value, the system uses the polynomial model to calculate appropriate flow rates directly, significantly reducing the time and resources required while maintaining processing quality.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP3878594B1Assist gas flow rate calculation device and calculation method
Publication Date: 2023.03.29 AMADA CO LTD
  • EP3878594B1 patent drawingFigure 1
  • EP3878594B1 patent drawingFigure 2
  • EP3878594B1 patent drawingFigure 3A~3B

AI summary

Storage units 60, 70 store a first computer program calculating a flow rate of an assist gas with a linear function having a pressure of the assist gas in a processing head 35 as a variable, and a second computer program calculating a slope of the linear function with a function having a gap G from a tip end of a nozzle 36 to a surface of a workpiece W as a variable. A control unit 50 substitutes a value of the gap G into the function to calculate the slope of the linear function and substitutes the slope of the linear function and a value of the pressure of the assist gas into the linear function to calculate the flow rate of the assist gas.