电烙铁的温度（The temperature of the soldering iron）.doc

电烙铁的温度（The temperature of the soldering iron） The basic process of lead-free soldering assembly includes: A. Lead-free PCB manufacturing process; The 96.5 Sn / 3.5 Ag and 95.5 Sn / 4.0 Ag / 0.5 Cu cocrystallization and near-eutectic alloys for soldering paste. C. The 99.3 Sn / 0.7 Cu eutectic alloy system for wave peak welding application; D. for manual welding of 99.3 Sn / 0.7 Cu alloy system. Although these are all feasible process, but there are several big problems, implement such as raw material cost is still higher than the standard Sn/Pb process, the limitation on the moisture increased, requirements in wave soldering process maintain inert air condition (there should be adequate nitrogen Gas) and is likely to reflow soldering temperature up to the limit temperature range (235 ~ 245 ℃) and improve the hot requirements for various components and so on. In terms of lead-free alternatives, there is no set of universally accepted norms, and after many discussions with many professionals in the field, we have come to the following technical and application requirements: Many assembly manufacturers of metal prices require that the price of lead-free alloys cannot be higher than that of 63Sn / 37Pb, but unfortunately the cost of all unleaded substitutes is at least 35% higher than that of 63Sn / 37Pb. Metal cost is the most important factor in choosing lead-free solder and solder wire. When the solder paste is made, the cost of the technology is relatively high in total manufacturing cost, so the price of metal is not so sensitive. Melting point is big Most assembly manufacturer (not all) are minimum requirements solidus temperature is 150 ℃, in order to satisfy the requirement of the electronic equipment working temperature, liquid temperature is highest depends on the specific application. Wave solder welding rod: in order to successfully implement wave soldering, liquid phase temperature should be low In the furnace temperature 260 ℃. Manual/machine soldering tin