Contract PCB Assembly Tablet PC PCB
1. Process flow of PCB soldering
1.1 introduction for PCB board soldering process: manual plug-in, manual welding, repair and inspection are required during PCB board welding.
1.2 the technological process of PCB soldering is classified as component - plug-in - welding - cutting - inspection - dressing according to the list.
2. Process requirements for PCB soldering
2.1 process requirements for components
2.1.1 components must be treated for solderability before insertion. If the solderability is poor, component pins should be plated with tin.
2.1.2 after pin shaping, the requirement of pin spacing is consistent with that of pad hole spacing on the PCB.
2.1.3 the shape of component pins shall be conducive to the heat dissipation during components soldering and the mechanical strength after welding.
2.2 process requirements for insertion of components on PCB boards
2.2.1 the order of inserting and installing components on PCB board is first low then high, first small and then big, first light and then heavy, first easy and then difficult, first general components and then special components, and the installation of the last procedure cannot affect the installation of the next procedure.
2.2.2 after the component is inserted, its logo should be read in an easy-to-read direction and read from left to right as much as possible.
2.2.3 polar components shall be installed in strict accordance with the requirements on the drawing and shall not be misassembled.
2.2.4 the components insertion on PCB board should be evenly distributed and arranged in a neat and beautiful manner. Diagonal arrangement, three-dimensional crossing and overlapping arrangement are not allowed. One side is not allowed to be higher than the other side; Also do not allow long pins on one side and short pins on the other.
2.3 process requirements of PCB welding spot
2.3.1 strength of welding joint should be sufficient
2.3.2 reliable welding and electrical conductivity shall be guaranteed
2.3.3 solder joint surface should be smooth and clean
3. Electrostatic protection during PCB welding
3.1 principle of electrostatic protection
3.1.1 prevent the accumulation of static electricity in places where there may be static electricity, and take measures to control it in a safe range.
3.1.2 existing electrostatic accumulation should be quickly eliminated and released immediately.
3.2 electrostatic protection method
3.2.1 leakage and grounding.Grounding to any part that may or has produced static electricity, providing an electrostatic release channel.The buried ground line is used to establish "independent" ground line.
3.2.2 elimination of non-conductor static electricity: positive and negative ions can be generated by ion fans, which can generate static electricity.