Lead-free soldering

Last Update Time: 2019-01-05 14:18:20

    l  The lead pollution hazard

 

The lead pollution hazard in electronic products is highly dispersed on the component chip, the pin coating, the PCB protection layer, and the component solder joints, which cause great difficulties in recycling.

At present, when dealing with abandoned electronic products, when it is split into the printed board level, it is common practice to bury people underground as industrial waste, but with the erosion of acid rain, industrial waste buried underground in a weak acid environment, where the lead will be precipitated and dissolved in human groundwater, resulting in drinking water pollution

 

l  Development trend of lead-free welding technology

With the EU RoHS's regulations on lead-free, Japan's famous electronics manufacturers: PANASONIC/NATIONAL, SONY, TOSHIBA, PIONEER, NEC and so on. Since 2000, the lead free process has been guided. So far, the lead-free manufacturing has been basically implemented, and the "green environmental" household appliances are introduced in Japan and the European and American markets. In March 2003, the Chinese government was prepared by the Ministry of information industry for the management law on the prevention and control of pollution in the production of electronic information products. It banned electronic products containing lead (Pb) since July 1, 2006.

Therefore, due to environmental considerations, the use of lead-free solder electronic products will not enter the market. For electronic assembly enterprises, the application of lead-free soldering technology is a practical problem that must be solved before enterprises.

 

l  Lead-free soldering equipment

 

Due to the particularity of lead-free solders, lead-free welding process requires lead-free welding equipment to solve the welding defects brought by lead-free solder and the impact of solder on the equipment, preheating / tin furnace temperature rise, nozzle structure, oxide, corrosion, quenching after welding, flux coating, nitrogen protection and so on. The basic principle and process of lead-free soldering technology are the same as lead welding technology, but lead-free welding material, components and PCB have changed, so the process parameters must be changed. Mainly in the following aspects.

1.The lead-free thermal stability of the flux is required to be higher.

High Sn content and strong solubility of Fe at high temperature. The characteristics of lead-free solder determines the new lead-free soldering process and equipment.

 

2.The lead-free of components and PCB in the lead-free welding process, the lead-free technology of the components and PCB plating is relatively complex, it involves a wide range of fields, which is one of the reasons that the international environmental protection organization postpones the lead-free process, for a long time, the lead-free solder and the Sn-Pb PCB coating are included storage," lift-off " and other welding defects, equipment manufacturers have to overcome this phenomenon from the equipment. In addition, the requirements of the PCB manufacturing process are also relatively improved, and the material of PCB board and components requires better heat resistance.