Label:PCBA, Quality Control
Jul 13, 20236780
Nowadays, PCBA manufacturing is a mature processing method, which is mainly used for the high integration of electronic equipment processing. However, before the manufacturing, we must hold a pre-production meeting to plan everything. It is necessary to do well in the procurement and inspection of pcba electronic components. We strictly inspect related items to ensure that the parts are not faulty. Every operation is guaranteed to be regulated without extensive rework and maintenance.
1. Quality control of PCBA manufacturing
Pre-production meeting
It is especially important to hold a pre-production meeting after receiving an order. Many small manufacturers do not take this seriously. Not only is it easy to cause issues of quality and safety due to poor PCB design, but it also lead to a large number of rework and repair.
Procurement and inspection of electronic components
The procurement channels of electronic components must be strictly controlled. Avoid the second-hand and counterfeit materials. In addition, it is necessary to set up an inspection team to check everything to ensure that the components are free from failure.
For printed circuit board, check the temperature test of the reflow oven. Make sure that there is no defects such as flying filament through-hole blockage or leakage, board surface bending, etc.
What about integrated circuit? Check if the silkscreen is good. BOM should be stored at constant temperature and humidity.
SMT assembly
Solder paste printing and reflow furnace temperature control management system are the key points of assembly. We need to develop laser templates with high quality standards and high processing technology requirements. According to the needs of PCB, some enterprises need to continuously increase or decrease the steel wire mesh or U-shaped holes, and only need to make the steel wire mesh by themselves according to the process design requirements.
Among them, the temperature control system of the reflow oven is important for the wetting of the solder paste and the firmness of the steel mesh, which can be self-adjusted according to the normal SOP operation guidelines. In addition, strict implementation of AOI test data greatly reduces the defects caused by human influence factor analysis.
Plug-in processing
When talking about plug-in processing, the design of the wave soldering mold is the key. Sports engineers must continue to practice and summarize how to use molds to greatly improve productivity.
PCBA processing board test
According to the pcba test requirements, the tests include circuit test, functional test, combustion test (aging test), temperature and humidity test, drop test, etc.
2. Precautions in PCBA manufacturing
The minimum space distance between the copper foil and the board edge is 0.5mm. The minimum distance between the component and the board edge is 5.0mm. The minimum target distance between the pad and the board edge is 4.0mm.
The minimum gap between copper foils is 0.3 mm for single board and 0.2 mm for double board. When designing a double-sided board, pay attention to the components of the metal case. The case should be in contact with the pcb board. The top pad cannot be opened and must be sealed with silkscreen oil or solder paste oil.
There shall be no copper foil and components (or according to the requirements of the structural diagram) within the radius of the screw hole of 5 mm.
The pad size (diameter) of through-hole mounted components is generally twice the hole diameter, with a minimum value of 1.5 mm for double-sided boards and 2.0 mm for single-sided boards. If you can't use a round pad, you can use a round pad.