光模块PCB板边插头发白的改善研究

Research on improving the whitening around the outline of edge-board contact for optical module PCB

应用于光模块的印制电路板(PCB)通常有板边插头设计,现有加工工艺在插头外形成型时,周边的基材区容易产生发白不良。通过试验分析铣板叠数、叠构设计和铣板参数对发白不良的影响,最终确定叠构设计为导致发白不良的主要因素。从叠构设计着手进行改善,拼版设计时将板边插头前端排成与覆铜板材玻纤纬向平行,使插头前端铣削路径垂直于板料玻纤经向,铣削后发白位置集中在插头前端,再通过斜边去除白边。结果表明,上述方案可有效改善板边发白。

Printed circuit boards(PCBs)used in optical modules usually have a edge⁃board contact design plug design.When milling the shape of the edge⁃board contact design with the existing process technology,the base material area around the fingers is prone to whitening defects.In this study,the influence of the number of milling stacks,stack-up design,and the milling parameters on the whitening defect was analyzed through experiments,and finally the stack-up design was determined to be the main factor of the whitening defect.Therefore,the stack-up design needs to be improved as follows.For the panel design,the front end of the edge⁃board contact design is arranged parallel to the weft direction of the glass fiber of the copper clad laminate,so that the milling path of the front end of the edge⁃board contact design is perpendicular to the warp direction of the glass fiber of the base material.The whitening position after milling is concentrated in the front end of the edge⁃board contact design,and then the white edge is removed by beveling.The results show that the above method effectively solves the problem of board edge whitening.