How to Monitor Nitrogen Purity in Laser Cutting Applications

Nitrogen is a critical component in laser cutting processes, used primarily to shield the material from oxidation and create clean, precise edges. For manufacturers and engineers, ensuring the purity of nitrogen is not merely a technical requirement but a quality of laser cut and operational efficiency. Even small variations in purity can significantly affect the final output, making stringent monitoring essential for maintaining cutting standards.

Understanding the Role of Oxygen Analyzers 

Oxygen analyzers are specialized instruments that measure the concentration of oxygen in nitrogen gas. Since nitrogen is typically used in high-purity applications, even a small amount of oxygen can significantly impact performance. Lower oxygen levels correspond to higher nitrogen purity.  

Setting Oxygen Threshold Levels 

Establishing acceptable limits involves defining the maximum permissible oxygen level that ensures the required nitrogen purity, with this threshold varying based on the specific requirements of the laser cutting application. When the oxygen concentration exceeds this set threshold, it indicates a decrease in nitrogen purity, allowing for immediate detection and prompt corrective actions to prevent potential quality issues in the cutting process.  

Using Portable Oxygen Analyzers 

Portable oxygen analyzers are designed for ease of use, making them suitable for quick spot checks and short, defined periods of continuous monitoring. These analyzers can be easily introduced into the gas supply line near the laser cutting machine, facilitating real-time monitoring of nitrogen purity precisely where it matters most (see Oxygen Monitoring Location below). This ensures that the nitrogen used in the cutting process maintains the required purity levels, which is crucial for achieving optimal cutting performance and quality. 

To effectively use portable oxygen analyzers, there are several important considerations: 

Oxygen Monitoring Location 

Ensuring the purity of nitrogen used in laser cutting involves strategically placing oxygen analyzers at various points in the gas delivery system. First, installing analyzers at the nitrogen source is essential. This initial check measurement confirms that the nitrogen being supplied, from a nitrogen generator or bulk liquid supply, is of the required purity before it enters the supply line. By monitoring at the source, any issues with the primary nitrogen supply can be immediately detected and addressed, preventing contaminated gas from entering the N2 distribution system. 

Next, placing analyzers along the supply line is crucial. As nitrogen travels through the delivery system, it can potentially pick up impurities. By installing analyzers at various points along the supply line, you can detect any contamination introduced during gas transportation. This step helps identify and isolate sections of the supply line where impurities might enter, allowing for targeted maintenance and repairs. 

Finally, monitoring nitrogen purity at the point of use, near the laser cutting machine, ensures that the gas maintains its purity throughout the entire delivery process. This final check is critical as it verifies that the nitrogen reaching the laser cutting machine meets the required standards, ensuring optimal cutting performance and quality. 

PST’s Inert Gas Analyzer Solutions

SenzTx Oxygen Transmitter can be installed in the gas supply lines to continuously monitor the oxygen concentration within the nitrogen gas. The SenzTx is a compact and robust O2 transmitter that utilizes zirconia or electrochemical technology to give a reliable measurement of oxygen concentration.

Microx-OL is a wall-mounted analyzer specifically designed to measure oxygen concentrations in inert gases supplied under positive pressure. It uses zirconia or electrochemical technology, providing a dependable solution for measuring oxygen levels in both % and ppm ranges.

GPR-1600 Oxygen Analyzer can be integrated into the nitrogen gas supply system to continuously measure and ensure that the nitrogen used is free of oxygen impurities. The GPR-1600 provides real-time data on oxygen concentration, allowing for the early detection of oxygen contamination in the nitrogen supply. This proactive monitoring prevents issues like material waste, rework, or machine downtime caused by impure nitrogen, ultimately leading to more efficient operations.

Maintaining Gas Quality 

Regular calibration of oxygen analyzers is essential to maintaining the quality of nitrogen used. Accurate readings depend on proper calibration, which should be performed using reference gases. Regular calibration ensures the analyzers' reliability, providing consistent and accurate monitoring of nitrogen purity. 

In addition to calibration, routine checks help detect any fluctuations in gas quality and allow for timely interventions to correct any issues. By regularly monitoring the nitrogen supply, you can ensure that the gas remains within the acceptable purity levels required for laser cutting. 

When the oxygen level exceeds the acceptable threshold, immediate action is required. Developing a protocol for prompt corrective actions is essential. This protocol may include purging the system to remove contaminated gas, inspecting the supply line for leaks, or replacing the gas supplies. By having a clear and immediate response plan, you can quickly address any deviations in nitrogen purity, ensuring a continuous, high-quality gas supply for the laser-cutting process. 

For more information, read The Essential Role of Nitrogen in Laser Cutting Operations