Why should PCB be baked? Understand in one article

Everyone in the PCB manufacturing industry knows that a copper foil is attached to the insulating material on a copper-clad board, and then it is baked dry. If you look carefully, you will see that there will be shrinkage during the drying process, and stress in all directions will be generated. This is the source of stress. Secondly, the purpose of drying the PCB before drilling is actually the main dehumidification. The drying before PCB drilling is In order to remove the moisture in the board and reduce the internal stress; there is also printed solder mask after pressing, including characters, etc., which need to be baked. Before shipping and packaging, there is also a process of baking the pressing plate, which is also to remove moisture. The warpage of the baked plate has been greatly improved. The baking mentioned above can eliminate the internal stress of the PCB board, that is, stabilize the size of the PCB. Its most significant advantage is that it can dry the moisture in the pad after baking, strengthen the welding effect, and reduce the false welding and repair rate. However, baking will cause a change in the color of the PCB board, which will affect the appearance. Generally, the baking time is 100-120°C, and the baking time is about 2H. Don't bake for too long! If it is exposed to the air, it needs to be used up within a day, otherwise oxidation is prone to occur. Of course, this is not absolute. It also depends on the supplier's production capacity. Some OSPs have a relatively longer storage time. The following editor provides the PCB baking instructions for your reference: 1. If the PCB is sealed and unpacked for more than 5 days within 2 months of the manufacturing date, please bake it at 120 ±5°C for 1 hour. 2. If the PCB exceeds the manufacturing date 2 Please bake at 120 ±5℃ for 1 hour before going online. 3. If the PCB is 2-6 months past the manufacturing date, please bake at 120 ±5℃ for 2 hours before going live. 4. If the PCB is past the manufacturing date 6 Month to 1 year, please bake at 120 ±5℃ for 4 hours before going online. 5. The baked PCB must be used up within 5 days (put into IR REFLOW), and the PCB must be baked for another hour before it is used. It can be used online. 6. If the PCB is more than 1 year from the manufacturing date, please bake it at 120 ±5℃ for 4 hours before going online, and then send it to the PCB factory for re-spraying tin before going online. The above is why the PCB editor talks about PCB The reason why the circuit board needs to be baked, I hope it can help everyone. PCB has always insisted on using superb technical force, sophisticated production equipment, perfect testing methods, product quality higher than industry standards, and warm and thoughtful service to win Praise and welcome from merchants and users worldwide.