DFM_鋼網(wǎng)_PCB設(shè)計

1、DFM鋼網(wǎng)&PCB設(shè)計電信學院電子工藝與管理1SMT印刷工序中的DFM影響到印刷的設(shè)計因素：PCB的焊盤設(shè)計不同元器件所選用的開孔現(xiàn)狀和尺寸不同焊點所需焊料量同一PCB上的開孔尺寸差鋼網(wǎng)設(shè)計鋼網(wǎng)厚度鋼網(wǎng)的加工方法鋼網(wǎng)開孔2鋼網(wǎng)設(shè)計鋼網(wǎng)厚度鋼網(wǎng)的加工方法鋼網(wǎng)開孔34鋼網(wǎng)設(shè)計要求鋼網(wǎng)開孔設(shè)計：寬厚比1.5面積比0.66開孔尺寸：焊盤尺寸J型和翼型引腳0.41.3mm pitch開孔寬度焊盤寬度（0.030.08mm）PBGA開孔直徑焊盤直徑0.05mmCBGA開孔直徑焊盤直徑（0.050.08mm）56QFP器件的引腳間距與鋼網(wǎng)厚度加工對象引腳中心距/mmPCB焊盤寬度/mm鋼網(wǎng)厚度/mmQFP0

2、.650.330.15QFP0.50.250.15QFP0.30.150.17開孔焊盤開孔焊盤開孔焊盤圓弧貼片阻容元件鋼網(wǎng)開孔8MELF和印膠鋼網(wǎng)開孔MELF印膠開孔焊盤除此兩處之外其他均為圓角印膠開孔焊盤印膠鋼網(wǎng)厚度一般為：0.150.2mm開孔位置：元件兩焊盤中心開孔寬度：1/3的焊盤內(nèi)邊距開孔長度：110的焊盤寬度鋼網(wǎng)開孔尺寸應(yīng)該與元件的具體尺寸一致。910工藝邊和定位孔識別標志定位孔：用于機械定位要求：孔壁光滑，不要有涂覆層；周圍2mm內(nèi)無銅箔工藝邊：一般為58mm組裝過程中設(shè)備夾持所需的距離工藝邊內(nèi)不可以布元器件11Fiducial Mark常用標識：作用：定位、位置校正設(shè)置原則：P

3、CB定位時：至少需要兩個應(yīng)不對稱設(shè)置？元器件定位時：僅針對貼片江都要求高的元器件？置于元器件對角上12拼板設(shè)計？拼板的連接方式？拼板的工藝邊？拼板的定位孔？拼板的mark點13元器件方向設(shè)計14焊盤與導線關(guān)系xx15元器件之間的間隙？1617Resistor Pad Design18Resistor Pad Design19Resistor Pad Design20SOT23 Pad Design21SOT23 Pad Design22SOT23 Pad Design23IC Pad Design24Electrical assembly types2526Examples of typica

4、l package styles and package descriptive designators27Lead-form (or terminal-shape) examples28Pro examples29Example of C1206 capacitor dimensioning for optimum solder fillet conditions30Pro of a gullwing leaded SOIC31Recommended minimum land-to-land clearances32Component orientation for wave solder

5、applications33Alignment of similar components34Fiducials 35Fiducial types for vision systems & clearance requirements36Fiducial locations on a printed circuit board37Land pattern to via relationships38Examples of via positioning concepts39Vias under components40Conductor characteristics41Examples of

6、 modified landscapes42Typical copper glass laminate panel43Conductor clearance for V-groove scoring44Breakaway (routed pattern)45Routed slots46Gang & Pocket solder mask window47Component temperature limits48General description of process validation contact pattern and interconnect49Photo image of IPC-A-49 test board for primary side50Flat ribbon, L, and gullwing lead joint description51Round or flattened (coined) lead joint description52Test via grid concepts53General rel