第1页共113页编号:时间:2021年x月x日书山有路勤为径,学海无涯苦作舟页码:第1页共113页SMT整个工艺流程细讲一、SMT工艺流程简介.........................................................................................................4二、焊接材料..........................................................................................................................6锡膏..........................................................................................................................................6锡膏检验项目..................................................................................................................9锡膏保存,使用及环境要求...........................................................................................9助焊剂(FLUX)....................................................................................................................9焊锡:....................................................................................................................................11红胶........................................................................................................................................11洗板水....................................................................................................................................12三、钢网印刷制程规范.........................................................................................................13锡膏印刷机(丝印机).........................................................................................................13SMT半自动印刷机(PT-250)作业规范.........................................................................13刮刀(squeegee)...............................................................................................................14真空支座........................................................................................................................14影响因素................................................................................................................................151.钢网/PCB精确对位:.............................................................................................152、消除钢网支撑架的厚度误差:...............................................................................153、消除PCB的翘曲:.................................................................................................164、印刷时刮刀的速度:.............................................................................................165、刮刀压力:............................................................................................................166、钢网/PCB分离:.....................................................................................................167、钢网清洗:............................................................................................................178、印刷方向:..............................................................................................................179、温度:......................................................................................................................1710、焊膏图形的印刷后检测:.....................................................................................17焊膏图形的缺陷类型及产生原因........................................................