Description

<style>.e_editor{font:14px/24px Roboto,Helvetica,Tahoma,Arial,'Microsoft YaHei','b8bf53';}.e_editor div,e_editor p,e_editor td,e_editor th,e_editor li{font-weight:inherit;font-size:inherit;font-style:inherit;font-family:inherit;}.e_editor ul{margin:-10px 0 20px;}.e_editor li{padding:5px 0;}.e_table{width:96%;border-collapse:collapse;empty-cells:show;}.e_table th,.e_table td{padding:5px;border:2px solid #eee;}.e_img{padding:10px 0;text-align:center;}.e_p{line-height:20px;padding:0 0 20px;text-indent:0em;}</style><p> Via holes paly the role of interconnected conduction. The development of the electronics industry promotes the development of PCB, putting forward higher requirements on <a href="https://www.allpcb.com/pcb_production" target="_blank">PCB production</a> process and surface mount technology. The plug hole process appears and meets the following requirements: </p><p> (A) the inner hole can be copper; solder can be plug can not plug; </p><p> (B) must have tin lead lead, there is a certain thickness requirements (4 microns) and shall not have <a href="https://www.allpcb.com/soldermask/soldermask_types.html" target="_blank">solder resist</a> ink into the hole, resulting in tin beads in the hole; </p><p> (C) vias must have solder mask ink plug hole, not light, no tin ring,and have tin beads and leveling requirements. </p><p><img src="https://jpfile1.oss-cn-shenzhen.aliyuncs.com/allpcb/web/image/20190605/6369534681993134755204046.png" alt="150700447.png"/></p><p> There are five main roles of plug hole: </p><p> (A) to prevent PCB a short circuit caused by tin from the through-hole to the element surface in <a href="https://www.allpcb.com/sns/how-flexible-board-are-manufactured_26249.html" target="_self" title="How Flexible Board Are Manufactured?">wave soldering</a>; especially when we put the vias on the BGA pad, you must first do plug hole, and then gold-plated for easy BGA welding. </p><p> (B) to avoid the flux residue in the vias; </p><p> (C) after electronic plant surface mount and component assembly, the PCB will be only finished in the test machine to form a negative pressure in vacuum </p><p> (D) to prevent the surface of the solder paste into the hole, affecting the placement; </p><p> (5) to prevent the wave soldering tin beads when the pop-up, resulting in short circuit. </p>