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1、DFM钢网&PCB设计电信学院电子工艺与管理2021/9/171SMT印刷工序中的DFM影响到印刷的设计因素：PCB的焊盘设计不同元器件所选用的开孔现状和尺寸不同焊点所需焊料量同一PCB上的开孔尺寸差钢网设计钢网厚度钢网的加工方法钢网开孔2021/9/172钢网设计钢网厚度钢网的加工方法钢网开孔2021/9/1732021/9/174钢网设计要求钢网开孔设计：宽厚比1.5面积比0.66开孔尺寸：焊盘尺寸J型和翼型引脚0.41.3mm pitch开孔宽度焊盘宽度（0.030.08mm）PBGA开孔直径焊盘直径0.05mmCBGA开孔直径焊盘直径（0.050.08mm）2021/9/1752021
2、/9/176QFP器件的引脚间距与钢网厚度加工对象引脚中心距/mmPCB焊盘宽度/mm钢网厚度/mmQFP0.650.330.15QFP0.50.250.15QFP0.30.150.12021/9/177开孔焊盘开孔焊盘开孔焊盘圆弧贴片阻容元件钢网开孔2021/9/178MELF和印胶钢网开孔MELF印胶开孔焊盘除此两处之外其他均为圆角印胶开孔焊盘1.印胶钢网厚度一般为：0.150.2mm2.开孔位置：元件两焊盘中心3.开孔宽度：1/3的焊盘内边距4.开孔长度：110的焊盘宽度钢网开孔尺寸应该与元件的具体尺寸一致。2021/9/1792021/9/1710工艺边和定位孔识别标志定位孔：用于机械
3、定位要求：孔壁光滑，不要有涂覆层；周围2mm内无铜箔工艺边：一般为58mm组装过程中设备夹持所需的距离工艺边内不可以布元器件2021/9/1711Fiducial Mark常用标识：作用：定位、位置校正设置原则：PCB定位时：至少需要两个应不对称设置？元器件定位时：仅针对贴片江都要求高的元器件？置于元器件对角上2021/9/1712拼板设计？拼板的连接方式？拼板的连接方式？拼板的工艺边？拼板的工艺边？拼板的定位孔？拼板的定位孔？拼板的？拼板的mark点点2021/9/1713元器件方向设计2021/9/1714焊盘与导线关系xx2021/9/1715元器件之间的间隙？2021/9/171620
4、21/9/1717Resistor Pad Design2021/9/1718Resistor Pad Design2021/9/1719Resistor Pad Design2021/9/1720SOT23 Pad Design2021/9/1721SOT23 Pad Design2021/9/1722SOT23 Pad Design2021/9/1723IC Pad Design2021/9/1724Electrical assembly types2021/9/17252021/9/1726Examples of typical package styles and package de
5、scriptive designators2021/9/1727Lead-form(or terminal-shape)examples2021/9/1728Profile tolerancing examples2021/9/1729Example of C1206 capacitor dimensioning for optimum solder fillet conditions2021/9/1730Profile dimensioning of a gullwing leaded SOIC2021/9/1731Recommended minimum land-to-land clear
6、ances2021/9/1732Component orientation for wave solder applications2021/9/1733Alignment of similar components2021/9/1734Fiducials 2021/9/1735Fiducial types for vision systems&clearance requirements2021/9/1736Fiducial locations on a printed circuit board2021/9/1737Land pattern to via relationships2021
7、/9/1738Examples of via positioning concepts2021/9/1739Vias under components2021/9/1740Conductor characteristics2021/9/1741Examples of modified landscapes2021/9/1742Typical copper glass laminate panel2021/9/1743Conductor clearance for V-groove scoring2021/9/1744Breakaway(routed pattern)2021/9/1745Rou
8、ted slots2021/9/1746Gang&Pocket solder mask window2021/9/1747Component temperature limits2021/9/1748General description of process validation contact pattern and interconnect2021/9/1749Photo image of IPC-A-49 test board for primary side2021/9/1750Flat ribbon,L,and gullwing lead joint description2021/9/1751Round or flattened(coined)lead joint description2021/9/1752Test via grid concepts2021/9/1753General relationship between test contact size and test probe misses2021/9/1754Test probe feature distance from component2021/9/1755