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SMT钢网通用开口规范1，无铅锡膏开口规范：CHIP元件元件名称开孔形状内距开孔PAD0402S16时，S=1616S18时，1：118S时，S=18W1：1，L20时，L外括2mil,大于22时1:1，最大为24*280603S28时S=2828S34，S1：1S34时，S=34宽度1:1开孔，长度外加3-4mil.裸铜宽加2-3mil.0805S38时S=3838S44，S1：1S44时，S=44宽度1：1开孔，长度外加4mil，裸铜宽度加3-4mil.1206及以上当S70时，内距1：1，当小于70时内距加大6mil.内距小于50时，加大8-12mil.宽度1：1开孔，长度外加5-6mil,裸铜板宽度加4mil.二极管0805)，当S40时，内中扩大8-12mil.大于40时，加大4-8mil.宽度1：1，长加4-6mil1206):内距大于78时，1：1，内距小于78时，内切至78。最大内切不超过10mil.宽度1：1，长加6-8mil三极管当S40时，PAD两边外移至40mil.焊盘一般1：1开孔，裸铜板外加2-3mil.高电容内距各内切4mil宽度1：1开，长度外加6-8mil.电晶体固定脚内切三分之一，如果大于120mil时，需要用0.3线宽做架桥处理.引脚可外括4-6mil.单排连接器引脚宽度可根据ICpitch值来开,如pitch值大于0.5mm时,外扩6-12mil,内切4-6mil.固定脚,即耳朵外移4mil,上下各加2mil.四脚晶振类长宽各外移2mil,中间切三分之一的方角.五脚IC三只脚宽度按ICpitch值为标准或略大,然后两边脚外移1mil,长外加6-8mil.两只脚按1:1,或略缩2mil,再外扩4-6mil.大电感内距各内切4-6mil宽度1:1.长外加8-12mil,裸铜板宽加4mil,中间架0.3宽度板.0402排阻排容Pitch值为0.5mm,内距保持到18-20mil.脚宽度8.8mil,长外加6-8mil.如外四脚较大,则相应缩小,并向两边外移缩小的二分之一.0603排阻排容Pitch值为0.8mm,内距保持到30-32mil.脚宽度16mil,长外加8mil.如外四脚较大,则相应缩小,并向两边外移缩小的二分之一.SW开关内切2mil,外扩6-8mil,如两边有小脚,小脚外扩2-4mil.如要求锡量多,靠上下两侧可再扩4mil.0.4pitch15-.7mil宽度开7.2mil,长度可外扩4-6mil.开金手指状内切2mil0.5pitch19.7mil宽度开8.8-9.2mil,长度可外扩6-8mil.开金手指状.内切2mil0.65pitch25.6mil宽度开12-13mil,长度可外扩6-10mil.开金手指状.内切2mil0.8pitch31.5mil宽度开16-17mil,长度可外扩8-10mil.内切2mil1.0pitch39.37mil宽度开20-22mil,长度可外扩8-10mil.内切2mil1.27pitch50mil宽度开24-27mil,长度可外扩8-12mil.内切2milQFP0.4pitch15.7mil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等零件三极管LW1L1WW1=1/3WL1=1.1L若W低于30mil时，W1=1/2=1/3WL1=1.1L若W低于30mil时，W1=1/2W功率晶体管比照此做法WW1LW1=1/3W长度与L相等WLDL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DD1/41/41/41/41/41/41/41/4W圆大小以QFP短边为主做1/4W，平均放中央五颗。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