PCB plug hole technology~

The through hole plays the role of connecting and conducting lines . The development of electronic industry , It also promotes PCB The development of , It also puts forward higher requirements for PCB manufacturing process and surface mount technology , Plug hole technology came into being .

Detailed explanation PCB Plug hole process of circuit board ：

One 、 Plug hole technology after hot air leveling

Adopt non plug hole process for production , After hot air leveling, use aluminum plate screen or ink screen to complete the through holes and plug holes of all fortresses . The process flow is ： Plate surface resistance welding → Hot air leveling → Plug hole → curing .
This process can ensure that the through hole will not drop oil after hot air leveling , But it is easy to cause the plug hole ink to pollute the board 、 out-of-flatness .

Two 、 Hot air leveling front plug hole process

1、 Plug the hole with aluminum sheet 、 curing 、 After grinding the plate, transfer the graphics
This process uses CNC drilling machine , Drill holes in aluminum plugs , Make a screen version , Conduct plug hole . The process flow is ： Before processing → Plug hole → Grinding plate → Graphic transfer → etching → Plate surface resistance welding .
This method can ensure that the through hole plug hole is flat , Hot air leveling will not explode oil 、 Quality problems such as oil falling off the hole , But this process requires one-time thickening of copper , High requirements for copper plating on the whole board .  
2、 Plug the hole with aluminum sheet and directly screen the plate surface to resist welding
This process uses CNC drilling machine , Drill holes in aluminum plugs , Make a screen version , Install it on the screen printing machine to plug holes , Park no more than 30 minute , use 36T Screen direct screen printing plate surface resistance welding . The process flow is ： Before processing — Plug hole — Silk screen — Pre drying — Exposure and development — curing
This process can ensure that the oil on the cover of the through hole is good , The plug hole is flat , After hot air leveling, the through hole is not tin , No tin beads are hidden in the hole , But it is easy to cause the solder pad on the ink in the hole after curing , Poor weldability, etc .
3、 Aluminum plug hole 、 development 、 Pre curing 、 Conduct resistance welding on the plate surface after grinding
Use CNC drilling machine , Drill the aluminum sheet with the required plug hole , Make a screen version , Install it on the shift screen printing machine to plug holes , The plug hole must be full , After curing , Grind the plate for surface treatment . This process is ： Before processing — The plug hole is pre baked — development — Pre curing — Plate surface resistance welding
This process can ensure that oil does not fall out of the through hole after hot air leveling 、 Oil explosion , However, it is difficult to completely solve the problem of tin on through-hole tin beads and through-hole tin .
4、 The plate resistance welding and plug hole are completed at the same time
This method uses 36T(43T) Wire mesh , Installed on the screen printing machine , Use a backing plate or nail bed , While finishing the board surface , Plug all the through holes . The process flow is ： Before processing -- Silk screen -- Pre drying -- Exposure -- development -- curing .
This process takes a short time , High utilization of equipment , It can ensure that oil does not fall out of the through hole after hot air leveling 、 There is no tin on the through hole , However, due to the use of silk screen to plug holes , There is a lot of air in the via , Create voids , out-of-flatness , There is a small amount of tin in the through hole .

The above is the detailed explanation PCB Plug hole process of circuit board , I hope it will help my friends .
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