3/10/2023 0 Comments Solder paste reflowAppropriate cooling can restrain redundant intermetallic compound formation or thermal shock to the components. And the practical reflow process refers to the flux to reduce the surface tension at the metal joint so that achieve metallurgical bonding, allow the individual solder powder spheres to combine and melt.Ĭooling : it needs to be done in a way without any stress to the components for the cooling boards after reflow. The solder is melting here and create the necessary solder joints. Reflow : the area of reflow is the area where get to the highest temperatures in the soldering process. The other is to active the flux and remove the solder paste solvents or volatiles. There are two reasons why the card us maintained at temperature, one is to make sure any areas that are not fully heated due to shadowing effects come up to the necessary temperature. Thermal soak : after the board is rising in temperature, it will go into the thermal soak area. In general, the temperature rise for infrared reflow soldering is between 2 and 3℃ per second, but it may be down to 1℃ per second on some occasions. However, it may not achieve the necessary temperature if it’s too slow. In addition, some areas may not get to the necessary temperature due to the thermal mass if the temperature of PCB is too quick. However, it may be damaged by the thermal stress if the rate is too high. Preheat : the board need to be steadily up to the necessary temperature. There are usually four stages as follows: It can make sure the resultant solder joints have the highest quality if correctly analyse the temperature of the reflow tunnel or chamber. The reflow process is made up of a lot of individual processes, which make sure there will not be any acceptable levels of thermal shock since the board is up to the correct temperature for reflow soldering. It will be difficult to rework if the components glue to the board, then what’s worse, all the components in place will move to the reflow soldering machine. In fact, it is enough for normal handing, but there are some tips you need to know. The pick and place machine places the components onto the board, and it can remain in place with the surface tension of solder paste. As usual using the automatic pick and place machine as it can’t work when using the manual placement to the numbers of components and necessary accuracy. Pick and place : it can fix the components in place with the solder paste on the board. Then having been added the solder paste to the board after adding, it can go on to the next stage. And it only allows the solder paste to be added to the PCB areas where it’s required. There is the solder resist layers on the board, but it’s essential to only add solder paste to the areas that require soldering, which is done by using the solder mask and solder paste machine. And the solder paste is only used for the areas that require soldering. Solder paste : substantively applying the solder paste to the board. Now PCBGOGO will explain the stage what is it. Use the solder paste and components to the board is the first stage in reflow soldering for PCB assembly. And it’s the best for use with components used in mass produced electronics products. Reflow soldering technology, making it possible to reliably solder surface mount components, especially the components with very fine pitch leads. What’s more, heating can be done by passing the assembly with the reflow oven as well as under an infrared lamp or by soldering individual joints with a desoldering hot air pencil. The solder paste reflows in a molten stage to create the permanent solder joints. Reflow soldering is a process, which using the solder paste to connect one or thousands of tiny electrical components to their contact pads, and then it will control the whole assembly by heating. The purpose of reflow soldering is to be acceptable soldering joints with pre-heating the components/PCB/solder paste first and then melting the solder, which instead of overheating without damage. It offers credible soldering for the all kinds of the sizes of component and pad required, as well as making it easy to control. When it comes to PCB assembly process, reflow soldering is the most widely used method of soldering, which is widely used for PCB assembly. Explaining Reflow Soldering for PCB Assembly by PCBGOGO
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