摘要
部分设计工程师在印制电路板(PCB)上设计了压接孔,压接孔的孔径公差一般要求±0.05 mm,增加了制作难度.以一款PCB的压接孔制作为例,从PCB钻孔加工的钻头选择、电镀均匀性、不同电镀设备及电镀电流方式下的电镀深镀能力(TP)、表面处理厚度等方面对压接孔的影响因素进行分析.研究分析结果表明,表面处理为化学镀镍金、有机可焊性保护剂、浸银、浸锡等PCB产品,其影响压接孔孔径变化的主要因素是不同电镀设备及电镀电流方式下的TP.
Abstract
The design engineers design crimping holes on printed circuit board(PCB).The aperture tolerance of crimping hole is generally required to be±0.05 mm.The compensation value increases the difficulty of making the crimping hole.In this paper,taking the manufacture of a PCB crimping hole as an example,the influencing factors of crimping hole are analyzed from the aspects of drilling bit selection,electroplating uniformity,electroplating throwing power under different plating equipment and electroplating current modes,surface treatment thickness and so on.The research and analysis results show that for the PCB products with the surface treatment such as electroless nickel gold,organic solderability protectant,electroless silver immersion,electroless tin immersion,etc.,the main factor that affects the aperture change of the crimping hole is the electroplating throwing power under different plating equipment and electroplating current modes.
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