Laser Assist Gas Jet Tuning for Plasma-Free Melt Ejection
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Solution Overview
Problem
Existing laser processing systems face challenges in effectively blowing out melted material from workpieces using assist gases, often resulting in plasma generation and contamination due to the proximity of the nozzle and workpiece, which affects finishing quality and nozzle integrity.
Innovation Solution
A laser processing system with a nozzle that forms a maximum point of velocity of the assist gas jet away from the emission opening, allowing the gas to be blown at a higher velocity to the workpiece, and a jet observation apparatus to determine the optimal positioning of the nozzle based on measured sound data, ensuring the workpiece is placed within a Mach disk region for enhanced gas utilization and reduced plasma generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the nozzle is positioned close to the workpiece to effectively blow out melted material, then the assist gas can remove material more effectively, but plasma generation and nozzle contamination increase
Solution Approach 1:
The patent changes the physical parameters of the assist gas by creating a jet flow with a maximum velocity point at a specific distance from the emission opening. By positioning the workpiece at this maximum velocity point, the system achieves optimal material removal effectiveness while avoiding the harmful effects of plasma generation and contamination that occur at closer distances.
Solution Approach 2:
The assist gas jet acts as an intermediary between the laser beam and the workpiece. By forming a jet with a maximum velocity point away from the emission opening, the gas mediates the interaction in a way that maximizes material removal while minimizing harmful plasma generation and contamination of the nozzle.
2Productivity
If the assist gas is emitted at high velocity to blow out melted material, then material removal effectiveness improves, but the nozzle must be positioned at an optimal distance that is difficult to determine
Solution Approach 1:
The patent employs acoustic emission detection as a feedback mechanism to identify the optimal nozzle positioning. By measuring the sound generated by the jet flow, the system can detect the maximum velocity point of the jet, providing real-time feedback that guides the positioning of the workpiece or nozzle to achieve optimal material removal effectiveness.
3Reliability
If the nozzle is positioned away from the workpiece to avoid contamination, then plasma generation and contamination decrease, but material removal effectiveness reduces
Solution Approach 1:
The patent transforms the assist gas emission into a jet flow with a specific velocity profile that has a maximum velocity point at a distance from the emission opening. This parameter change allows the system to position the workpiece at this maximum velocity point, simultaneously achieving high material removal effectiveness and avoiding plasma generation and contamination associated with closer positioning.
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 effectively utilizes the assist gas to remove melted material, improves finishing quality by preventing plasma generation, and reduces nozzle contamination by positioning the workpiece in regions where the assist gas velocity is maximized, thereby enhancing the laser processing outcome.
Implementation Method 1
the nozzle being configured to form a maximum point of velocity of the jet at a position away from the emission opening
Implementation Method 2
a measuring instrument configured to measure a sound generated by the jet impinging on an object
Data Source
AI summary
A laser processing system that can effectively blow out a material of a workpiece melted by a laser beam by effectively utilizing an assist gas emitted from a nozzle. The laser processing system comprising a nozzle including an emission opening configured to emit a jet of an assist gas along an optical axis of a laser beam, the nozzle being configured to form a maximum point of velocity of the jet at a position away from the emission opening; a measuring instrument configured to measure a sound generated by the jet impinging on an object; and a position acquisition section configured to acquire information representing the position of the maximum point based on output data of the measuring instrument.