Dynamic Process Gas Flow Control for Laser Welding

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Solution Overview

Problem

Existing methods for laser machining, such as welding of plate-like workpieces, tubes, and profiles, consume excessive process gas without optimizing gas usage, affecting the quality of the machining result and requiring complex control devices.

Innovation Solution

A method that initializes process gas supply based on a first default value during machining and automatically reduces it to a second, lower value after a stabilization time, allowing for significant gas savings without compromising the machining quality, using default values and stabilization times determined through testing and stored for automatic control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a high quantity of process gas is supplied per unit time during the entire machining process, then the machining quality is maintained, but the process gas consumption is excessive

Engineering Contradiction:
Improvemachining qualityVSAvoidprocess gas consumption
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The process gas supply is divided into two distinct periods: an initial period with higher gas flow rate to establish stable machining conditions, and a subsequent period with reduced gas flow rate to minimize consumption. This periodic variation in gas supply quantity resolves the contradiction between maintaining quality and reducing consumption.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

A sufficient quantity of process gas is supplied in advance during the initial period to establish stable gas flows and protect the machining area before the actual machining begins. This preliminary action ensures that when machining starts, the protective gas atmosphere is already in place, allowing for reduced gas consumption during the main machining phase.

Inventive Principle:
Principle #10Preliminary action

2Loss of substance

If the process gas quantity is reduced to save gas, then the process gas consumption decreases, but the machining quality may deteriorate

Engineering Contradiction:
Improveprocess gas consumptionVSAvoidmachining quality
Core Design Contradiction:
Loss of substanceVSManufacturing precision

Solution Approach 1:

The process gas supply quantity is made dynamic rather than static, adjusting automatically based on the machining phase. The system transitions from a high gas flow rate during the initial stabilization phase to a lower gas flow rate during the steady-state machining phase, ensuring quality is maintained when needed while reducing consumption when the process is stable.

Inventive Principle:
Principle #15Dynamics

3Stability of the object's composition

If the process gas quantity is reduced gradually, then the process stability is maintained, but the gas savings are less compared to abrupt reduction

Engineering Contradiction:
Improveprocess stabilityVSAvoidprocess gas consumption
Core Design Contradiction:
Stability of the object's compositionVSLoss of substance

Solution Approach 1:

The gas supply operates in periodic phases: an initial period with higher flow rate for stabilization, followed by a transition to a reduced flow rate period. This structured periodic action maintains process stability while achieving significant gas savings compared to continuous high-flow operation.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3013508B1Process for machining, in particular for mechanical welding, and control apparatus for a setting device of a process gas feed
Publication Date: 2020.04.15 TRUMPF LASER & SYSTEMTECHNIK GMBH
  • EP3013508B1 patent drawingFigure 1
  • EP3013508B1 patent drawingFigure 2
  • EP3013508B1 patent drawingFigure 3

AI summary

What is described is a process for machining, in particular for mechanically welding, workpieces, in particular plate-like workpieces, tubes and/or profiles, by means of a thermal processing beam (18), in particular by means of a laser beam, in which process a workpiece is processed with a relative movement between the processing beam (18) and the workpiece (3), wherein a process gas is fed to a processing zone (20) in a settable quantity of process gas per unit time. After an intended stabilization time, in which the processing of the workpiece is continued with a relative movement between the processing beam (18) and the workpiece (3), the quantity of process gas fed per unit time is reduced automatically. What is furthermore described is a control apparatus (24) of a setting device (23) for a process gas feed in accordance with such a process.