Printed circuit board is often referred to as PCB. PCB component is called PCB assembly service. Components on board can be SMT (surface mount) component, plug-in component, pressure component or assembly part. Today, take a common motherboard as an example to share the assembly process and common problems of PCBA factory.

After the ICT test station, it needs to go through an assembly station to install button battery, radiator, CPU base bracket, CPU backplane, handle, some isolating Mylar, plastic column for limit, screw, etc. Figure 1 shows the server motherboard with assembly.

When assembling parts, some external forces should be applied on PCBA, so PCBA should be fixed and supported on the assembly fixture before assembly. Some PCBA need to assemble the bottom surface of PCBA board, so two

supporting fixtures need to be made. The support fixture also needs to pass electrostatic protection and stress test before delivery to production line. The standard of electrostatic protection can refer to ANSI / ESD s20.20. Refer to ipc-jedec-9704a (L) for stress test.

The following describes the process and common problems of pcb assembly service according to the type of components. Battery:

There are two types of batteries on this motherboard: discrete type and horizontal type, as shown in Figure 2. Button batteries should be placed horizontally and can not be stacked or taken with bare hands. The battery stack and the bare hand take may cause the low power due to the discharge, reduce its service life. The battery needs to be stored in the original disk, as shown in Figure 3. The original battery tray is made of plastic material, which is easy to generate static electricity. It needs to use an ion blower to dissipate static electricity. Ion fan can produce a large number of positive and negative charge air flow, and neutralize the charge on the charged object.....More