Cross-jet nozzle deflects splatters in laser machining heads
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Solution Overview
Problem
During laser welding, the formation of a metal vapor flame and weld gases leads to thermal lens formation, causing energy input inhomogeneities and degrading weld quality, while metal splatters damage focusing optics due to uncontrolled deposition and burning.
Innovation Solution
A cross-jet nozzle is positioned close to the workpiece to generate a transverse air flow that deflects metal splatters and reduces the metal vapor flame height, combined with a protective gas system that uses laminar gas flow to protect the weld bead and optics, with a nozzle body made of copper for easy cleaning and adjustable mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a transverse air flow is generated by a cross-jet nozzle to deflect metal splatters and reduce metal vapor flame height, then weld quality is improved and optics are protected, but compressed air consumption increases
Solution Approach 1:
The cross-jet nozzle is positioned at a specific location close to the workpiece (at least 10 mm away) to create a localized transverse air flow exactly where the metal vapor flame and splatters are generated. This targeted approach protects the focusing optics and improves weld quality without requiring excessive compressed air consumption throughout the entire system.
2Manufacturing precision
If the cross-jet nozzle is positioned close to the workpiece to reduce metal vapor flame height, then weld quality and process stability are improved, but the risk of splatter deposition on the nozzle increases
Solution Approach 1:
The cross-jet nozzle generates a transverse air flow that deflects metal splatters away from the focusing optics before they can reach and damage the optics. By positioning the nozzle close to the workpiece, the protective air flow is created at the source of the problem, preventing splatter deposition on critical components.
3Stability of the object's composition
If a gas flow is directed onto the focused laser beam to protect it from metal vapor and welding gases, then thermal lens formation is reduced and energy input homogeneity is improved, but the complexity of the gas delivery system increases
Solution Approach 1:
The cross-jet nozzle combines multiple functions into a single component: it generates the transverse air flow that protects the focusing optics from splatters, reduces the metal vapor flame height, and stabilizes the thermal conditions in the processing zone. This integration simplifies the overall system compared to having separate systems for each function.
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 configuration improves weld quality, reduces splattering and depth variations, protects optics, and lowers compressed air consumption while maintaining a stable gas flow for oxidation prevention.
Implementation Method 1
a cross-jet nozzle for generating a transverse flow that passes through the focused laser beam transversely
Implementation Method 2
focusing optics for focusing a laser beam in a direction of a processing zone of a workpiece
Implementation Method 3
laser beam focused onto the workpiece by a laser processing head
Implementation Method 4
A part of the laser beam focused onto the workpiece by a laser processing head is absorbed by the metal vapor particles
Implementation Method 5
heated and therefore emit thermal radiation due to their very high temperature
Implementation Method 6
a protective gas system that uses laminar gas flow to protect the weld bead and optics
Data Source
AI summary
A laser machining head includes a focusing optical unit for focusing a laser beam in a direction of a machining zone of a workpiece and includes a cross-jet nozzle for producing a cross flow that passes through the focused laser beam transversely (e.g., at a right angle to) a beam axis of the focused laser beam. The distance of the cross-jet nozzle from the workpiece is less than 20 mm (e.g., between 8 mm and 12 mm). A nozzle body having a bottom opening that faces downward toward the workpiece is provided laterally adjacent to the focused laser beam. A protective gas flows out of the bottom opening, which is arranged below the cross-jet nozzle in order to entrain the protective gas flowing between the nozzle body and the workpiece due to the cross flow of the cross-jet nozzle so that the protective gas flows over the machining zone.