In an SMT line, reflow soldering is one of the most critical processes. Solder paste oxidizes easily at high temperatures, and oxidation causes defects such as cold solder joints, tombstoning, and solder voids — directly dragging down yield. To prevent oxidation, high-purity nitrogen (typically 99.9%–99.99%, depending on the product grade) must be injected into the reflow oven chamber.
Another key process is purging protection: using high-pressure, high-purity nitrogen to blow flux residues, particulate contaminants, and moisture off the PCB surface. This step directly affects the board’s surface insulation resistance and long-term reliability, and the nitrogen purity requirement is even higher here — usually ≥99.99%.
In addition, nitrogen is used in wave soldering, PCB/FPC baking, precision component storage, and other applications. Nitrogen can truly be called the “invisible shield” on an electronics manufacturing floor.
Three major pain points of liquid nitrogen
1. High cost with large fluctuations
The unit price of liquid nitrogen includes multiple cost layers: liquefaction, transportation, storage, and natural boil-off losses. Take a typical single SMT line as an example — nitrogen costs alone can reach RMB 200,000–300,000 per year (depending on gas consumption and local electricity rates). For a whole factory with multiple lines, the cost easily exceeds a million RMB. Moreover, liquid nitrogen pricing is subject to market volatility, making operating costs uncontrollable.
2. Unstable supply — the line waits for gas
Liquid nitrogen tanker deliveries are vulnerable to typhoons, blizzards, and logistics shutdowns during holidays like Chinese New Year. Once supply is interrupted, reflow soldering and purging stations come to a halt, and the entire production line is forced to slow down or even stop.
3. Uncertain purity, unpredictable yield
The purity of purchased liquid nitrogen cannot be monitored batch by batch in real time. If a particular batch falls short of the required purity, purging is incomplete and solder joints oxidize — yet the resulting batch defects often go unnoticed until final testing, at which point the damage is already irreversible.
A better solution: On-site nitrogen generation
1. Stable purity, visible in real time
On-site nitrogen generators provide real-time online monitoring of output purity, with immediate alarms if any abnormality occurs. The factory can verify nitrogen quality at any time, no longer relying on a supplier’s “batch certificate.”
2. Lower electricity cost — the air-to-nitrogen ratio is key
The core operating cost of on-site nitrogen generation is electricity. The key metric that determines electricity cost is the air-to-nitrogen ratio — the amount of compressed air consumed (at standard conditions) to produce one cubic meter of nitrogen. The lower the ratio, the more you save on power.
It’s important to understand that PSA nitrogen technology has a physical limit: the higher the purity, the faster the air-to-nitrogen ratio rises. Moving from 99.9% to 99.99% often causes the ratio to double; reaching ultra-high purity of 99.999% typically requires several times the energy consumption with a conventional design.
Take the Jiamai K-series nitrogen generator as an example. At 99.999% purity, its air-to-nitrogen ratio can be as low as 3.00, whereas achieving the same purity in the industry normally requires a higher ratio. This means that, at the same nitrogen output, Jiamai equipment saves more electricity than conventional designs.
3. Independent gas supply — no more waiting
Once the equipment is operational, as long as power supply is stable, it can produce nitrogen continuously 24 hours a day, 7 days a week — unaffected by weather, transport, or supplier issues.
The shift is happening
From Foxconn, Kinwong Electronic to Victory Giant Technology, numerous leading electronics manufacturers have already switched the nitrogen supply for their core processes — including reflow soldering and purging protection — to on-site generation.
Recently, a major international FPC manufacturer also chose the Jiamai K-series nitrogen generator (99.99% purity), specifically for the purging protection process on its production lines. Behind this order lies deep collaboration between a professional gas trader and the equipment manufacturer, and it further reflects a consensus that is forming across the electronics manufacturing industry: on-site nitrogen generation is more cost-effective, more stable, and more controllable.
