SMT钢网开孔规范(锡膏 红胶)

5.7mil宽度开7.2mil(0.18mm),内切4mil,外扩4mil.如长度超过80mil,则只内切,不外扩.0.5pitch19.7mil宽度开8.8-9.0mil(0.22-0.23),内切4mil,外加4–6mil.0.65pitch25.6mil宽度开12-12.5mil,长度内切4-6mil,外扩6-8mil.QFN0.4pitch15.7mil宽度同上,内切4-6mil,外拉6-8mil.0.5pitch19.7mil宽度同上,内切6-8mil,外加6-10mil.0.65pitch25.6mil宽度同上,同切6-8mil,外加8-12mil.BGA0.4pitch15.7mil直径开8.8mil.0.5pitch19.7mil直径开12mil.0.8pitch32mil直径外二圈做17mil,其餘做15mil1.0picth40mil直径外三圈做22mil,其餘做20mil1.27picth50mil直径外三圈做28mil,其餘做24mil2,点胶开口规范:CHIPC、R、L、D、F等零件LW1L1WW1=1/3WL1=1.1L若W低于30mil时,W1=1/2W三极管WW1L1LW1=1/3WL1=1.1L若W低于30mil时,W1=1/2W功率晶体管比照此做法排阻WW1LW1=1/3W长度与L相等LICL圆数量圆大小间距D150mil以下21/4W三等分151~400mil31/4W四等分401~600mil41/4W五等分600mil以上51/4W六等分WDDDQFP1/41/41/41/41/4圆大小以QFP短边为主做1/4W,平均放中央五颗。W1/41/41/4钢板厚度的选择:⑴一般点胶钢板厚度在0.2mm以上⑵点胶开口宽度小于8mil时,钢板厚度必须改为0.18mm⑶点胶开口宽度小于7mil时,钢板厚度必须改为0.15mm⑷开口宽度≧钢板厚度