In the process of welding with high-temperature solder bars
, there will always be various problems of poor welding, such as problems with solder joints, problems with drawing tips, problems with Qiaolian, etc. So what are the reasons for these problems? Let's take a look at the reasons for the incomplete solder joints.
The solder bar shows poor soldering, mainly because the flux of the solder bar is too heated, and the other is that the PCB board or the components themselves have quality problems.
If the lubrication of the solder bar and the solder wire is poor during the use of the solder bar, the first thing to think about is whether it is because the surface of the PCB board is oxidized, and there is a relatively severe oxide film, and there is another possibility that the ionic impurities in the solder bar are too much. . For the production workshop of solder bars, it takes time to keep clean and pollution-free. It is best to keep a sealed dust-free workshop for production, which is very helpful for the lubricity of solder bars.
When using a solder bar for welding, if the appearance of tin coating appears, which is what we usually call poor tin eating, there are four reasons for the appearance of the solder bar: one is that the preheating temperature of the solder bar is not good, Or the temperature of its own tin furnace is too low; the second is that the flux used in the solder bar is not active enough to assist the welding; the third is that the over-tin depth of the solder bar is not clear; the fourth is that the solder bar is affected during the welding process. serious pollution.
The difference between the low temperature solder bar and the high temperature solder bar is mainly due to the unevenness of the antioxidant content involved in the solder bar. Usually when working at high temperature, the temperature can reach 400~480C. Low-temperature solder bars and solder wires are made of high-purity lead-free tin wire. Under strict quality control conditions, through vacuum deoxidation treatment, the degree of oxidation and the content of metal and non-metal zinc can be effectively controlled. The solder surface of the low-temperature solder bar is evenly lubricated, with high purity, and has very good fluidity and test run.
The high-temperature solder bar is specially used in the environment with high tin immersion temperature, which can resist the oxidation of the tin surface and avoid impurities such as tin slag oxides on the tin surface. , The resulting tin surface is as bright as a mirror, which is the preferred environmental protection material for high temperature welding work.
From the selection of high-quality pure tin to the close process monitoring, to the final product shipment inspection, it is necessary to fully ensure the high solderability and high quality of lead-free solder bars and solder wires, two of the EU ROHS directives. The content of harmful substances lead and chromium is far lower than the international standard. The higher the lead content, the higher the melting point and the higher the corresponding working temperature.