PCBA Tech - PCBA electronic equipment assembly and placement process

Basic requirements for PCBA electronic equipment assembly

The assembly and connection technology of PCBA electronic equipment is abbreviated as electronic assembly technology. It is a combination of multiple technologies for assembling electronic parts and components into a complete machine according to design requirements. It is the main production link for manufacturing electronic complete machine products according to design requirements.

Assembly refers to the use of fasteners, adhesives, etc., to attach the electronic components of the product to the specified position as required, and assemble them into a new component until the final assembly of the product. The main connection methods include screw mounting, riveting, and Bonding, crimping, winding and surface mounting, etc.

The basic requirements for installation are as follows:

l. The installed parts, components, and entire parts must be qualified and meet the process requirements. There should be no scratches on the appearance and no damage to the coating.

2. When installing, the lead direction and polarity of the electronic components and mechanical mounting parts should be correct, and they should not be skewed, and the packaging shells of electronic components should not touch each other.

3. Electronic components to be mechanically installed should be fixed before welding, and should not be adjusted and installed after welding.

4. When installing various packages, they cannot be opened unless there are special requirements.

5. The moving parts of the machinery in the installation must be made to move smoothly and freely without blocking.

6. When installing, the foreign objects in the machine should be cleaned up to prevent the hidden danger of short circuit failure.

7. The places where lubricants, fasteners, and adhesives need to be coated during installation should be in place, uniform and appropriate.

8. When the insulated wire passes through the metal frame hole, there should be no tip burrs to prevent tip discharge.

9. When installing the ground wire welding piece with fasteners, remove the paint layer and oxide layer at the installation position to make good contact.

PCBA four major mounting process flow

With the development of PCBA assembly of electronic products in the direction of miniaturization and high assembly density, the electronic assembly technology is also dominated by surface SMT mounting technology. However, there are still a certain number of through-hole plug-in components in some PCB circuit boards. The assembly of both plug-in components and surface mount components is called hybrid assembly, or hybrid assembly for short, and assembly that uses all surface mount components is called full surface mounting.

The PCBA assembly method and its process flow mainly depend on the type of assembly components and the conditions of the assembly. It can be roughly divided into four types: single-sided mounting technology, single-sided mixed mounting technology, double-sided mounting technology and double-sided mixed mounting technology.

1. Single-sided mounting process

Single-sided mounting refers to the assembly where all components are mounted on one side of the PCB. The main flow of the single-sided mounting process: printing solder paste - patch - reflow soldering - cleaning - inspection - rework.

2. Single-sided mixed process

Single-sided mixed assembly refers to the components not only mounted components but also plug-in components, and the components are assembled on one side of the PCB. The main process of single-sided mixed assembly process: printing solder paste - patch - reflow soldering - plug-in -Wave soldering-cleaning-testing-rework.

3. Double-sided mounting process

Double-sided mounting refers to the assembly where all components are mounted and the components are distributed on both sides of the PCB. The main process of the double-sided mounting process: A side printing solder paste - patching - reflow soldering - plug-in - pin bending - flipping board - B surface point patch glue - patching - curing - flipping board - wave soldering - cleaning -Inspection-Rework.

4. Double-sided mixed packaging process

Double-sided mixing refers to the assembly of components not only mounting components but also inserting components, and the components are distributed on both sides of the PCB board . The main process of the double-sided mixed assembly process: A side printing solder paste - patch - reflow soldering - plug-in - pin bending - flipping - B surface point patch glue - patching - curing - flipping - wave soldering - cleaning -Inspection-Rework.