Analyzing of the poor PCBA device
一：Reasons for poor PCB device:
1.The Layout design problem Poor package design
2.The layout is too dense, resulting in links, misplaced
3.The patch pad copper foil is severely asymmetrical or large-area copper-clad, resulting in poor 4.soldering, monument, and displacement
5.There are holes on the pad to cause solder joint
6.Too large PCB can cause rocker, which leads to poor placement
二： Poor materials:
1.The welding of components and PCB causes poor soldering
2.The PCB board is short-circuited, open circuit, short, slightly open
3. PCB board rocker, national standard requires a rocker degree of less than 0.75%, the general requirements are 0.5%, depending on the size of the board and the ability of the processor
三：Improper PCB surface treatment：
1.PCB surface treatment is not proper, the pad is not flat
2. Assembly can not withstand high temperatures, resulting in cracking, deformation, damage
3.The stencil is too thick or too thin, resulting in solder joints, links
