Why does reflow soldering need to measure oxygen?

With the increase of assembly density and the emergence of fine pitch assembly technology, nitrogen-filled reflow soldering process and equipment have been produced, which has improved the quality and yield of reflow soldering, and has become the development direction of reflow soldering. Nitrogen reflow soldering has the following advantages:

  　(1)Prevent reduction of oxidation

  　(2)Improve welding wetting force and speed up wetting speed

  　(3)Reduce the production of solder balls, avoid bridging, and get better welding quality

How much oxygen concentration is appropriate?

Oxygen in nitrogen furnace, the basic standard is generally to achieve a certain oxygen contentPPMNot strictly.1%（10000PPM）,strict0.1%（1000ppm) below. It is particularly important that solder paste with lower active flux can be used, which can also improve the performance of solder joints and reduce the discoloration of the substrate. However, its disadvantage is that the cost increases significantly, and the increased cost increases with the amount of nitrogen. When you need to reach in the furnace1000ppmOxygen content and50ppmOxygen content, the general nitrogen content test is carried out by a matching online oxygen content analyzer. The oxygen content test principle is that the oxygen content analyzer is first connected to the collection point through nitrogen reflow soldering, then the gas is collected, and the oxygen content value is tested and analyzed by the oxygen content analyzer to obtain the purity range of nitrogen content.

How many points of oxygen monitoring?

There is at least one nitrogen reflow soldering gas collection point and more than three high-end nitrogen reflow soldering gas collection points. Different requirements for welding products and different requirements for nitrogen are very different. Solder paste manufacturers are now committed to the development of high oxygen content in the atmosphere can be good solder paste, so that you can reduce the consumption of nitrogen.

Here,recommend for everyone.2The sensor that detects oxygen is used together.

      1、O2S-FR-T2-18X

Temperature:

This zirconia sensor is threaded for easy fixing. Can be used in high temperature environment in reflow soldering, temperature range-100℃~250℃。

Range:

collocationOXY-LC-485, the board range is0.1%-100%They can work in air.

Input:

      8-28V

Output:

RS485 digital signal

      2、SO-B0-001

Temperature:

This Austrian limiting current oxygen sensor can be used in high temperature environments in reflow soldering with the highest temperature range350℃。

Range:

When the oxygen concentration in the reflow is lower0.1%When, on, range0.001%-0.1%, I .e.10ppm-1000ppm。

Input:

collocationGSBboard, a complete set of models namedEGa0202std-B0001。

Output:

Analog voltage:0-5V

Analog current:4-20mA

Digital signal:RS232