PCBA Tech - Double-sided PCB and PCBA processing and assembly

As products have higher and higher requirements for functions, ordinary single panels are no longer sufficient to meet the needs of functionalization. What emerged at the historic moment is the double-sided printed PCB circuit board. It means that there are conductive lines on both sides of the circuit board. It is usually made of epoxy glass cloth copper clad laminate. Used in the fields of communication electronic equipment, advanced instruments and meters, high-performance electronic computers, etc. The typical process for manufacturing double-sided plated-hole printed boards is the bare copper-clad solder mask process (SMOBC). The process is as follows:

Double-sided copper clad laminate blanking - composite board CNC drilling through hole inspection, deburring, brush electroless plating (through hole metallization) - (full board electroplating of thin copper) - inspection and cleaning of screen printing negative circuit patterns, curing (dry Film or wet film, exposure, development)-Check and repair circuit pattern plating-Plating tin (anticorrosive nickel/gold)-Remove printing material (photosensitive film)-Etching copper-(Removing tin) and cleaning brush a layer of thermal curing green oil wire Screen printing solder mask pattern (photosensitive dry film or wet film, exposure, development, heat curing, ordinary photosensitive heat) curing and oil recording)-cleaning, drying screen printing marking character graphics, curing-(spray tin or organic solder mask Mold)-shape processing clean, dry, electrical switch test, packaging inspection, finished product delivery.

Assembly of finished PCBA processing products

1. Prepare the materials, equipment and tools needed for circuit board assembly

1. One DC stabilized power supply and one multimeter;

2. The circuit board that has been welded;

3. The kit and shell of the product to be assembled, and the list of related accessories of the machine;

4. Electric screwdriver, rag, electronic label (product identification code);

2. Inspection before assembly

1. Detailed inspection and circuit board inspection of the list to be assembled

2. Check the product shell

3. Check the outer shell of the product kit for defects and damage.

4. Inspect the printed board. Visually check whether the printed board is intact, whether the solder resist coating on the surface is intact, and whether there are obvious short circuits and short circuit defects. Use a multimeter to detect whether there is a short circuit between the power supply and the ground on the printed board.

Three, final assembly and shipment

1. The board with BGA and IC should use heat-dissipating glue and anti-collision pad;

2. Align the printed board and put it in the shell. Align the screw holes, pay attention to the floating resistors and other components not to collide with the shell;

3. Install the screws to fix the printed circuit board, cover the shell and screw the final assembly screws;

4. Check the appearance for damage and other appearance defects;

5. Put the product label;

6. Transfer to the back-end such as aging test;

The entire PCBA assembly process is roughly like this. If there are special process requirements, it can be improved according to the relevant technical requirements of DFM.