Процесс производства SMT

The basic process components of SMT include: screen printing (or glue dispensing), mounting (curing), reflow soldering, cleaning, testing, and repair. 1. Screen printing: Its function is to leak solder paste or patch adhesive onto the solder pads of the PCB, preparing for the soldering of components. The equipment used is a screen printing machine, located at the front end of the SMT production line. 2. Glue dispensing: It is the process of dropping glue onto a fixed position on the PCB, primarily used to secure components onto the PCB board. The equipment used is a dispensing machine, located at the front end of the SMT production line or behind the testing equipment. 3. SMT: Its function is to accurately install surface assembled components onto the fixed position of the PCB. The equipment used is a surface mount machine, located behind the screen printing machine in the SMT production line. 4. Curing: Its function is to melt the patch adhesive, thereby firmly bonding the surface assembled components and PCB board together. The equipment used is a curing oven located behind the surface mount machine in the SMT production line. 5. Reflow soldering: Its function is to melt the solder paste and firmly bond the surface assembled components and PCB board together. The equipment used is a reflow soldering furnace, located behind the surface mount machine in the SMT production line. 6. Cleaning: Its function is to remove harmful soldering residues such as soldering flux on the assembled PCB board. The equipment used is a cleaning machine, which can be located in a non fixed position and can be online or offline. 7. Testing: Its function is to inspect the welding and assembly quality of the assembled PCB board. The equipment used includes magnifying glass, microscope, online testing instrument (ICT), flying needle tester, automatic optical inspection (AOI), X-RAY detection system, functional tester, etc. The location can be configured in a suitable place on the production line according to the needs of the detection. 8. Repair: Its function is to rework PCB boards that have been detected as faulty. The tools used are soldering iron, repair workstation, etc. Configure at any position on the production line. 1, Single sided assembly: Incoming inspection=>Silk screen solder paste (dot patch adhesive)=>SMT=>Drying (curing)=>Reflow soldering=>Cleaning=>Testing=>Repair 2. Double sided assembly: A: Incoming inspection=>Silk screen solder paste (dot patch adhesive) on the A-side of the PCB=>SMT=>Drying (curing)=>Reflow soldering on the A-side=>Cleaning=>Flip over=>Silk screen solder paste (dot patch adhesive) on the B-side of the PCB=>SMT=>Drying=>Reflow soldering (* Good only for B-side=>Cleaning=>Testing=>Repair) This process is suitable for use when larger SMD such as PLCC are attached to both sides of the PCB. B: Incoming inspection=>PCB A-side silk screen solder paste (dot patch adhesive)=>SMT=>drying (curing)=>A-side reflow soldering=>cleaning=>flipping=>PCB B-side adhesive patch=>SMT=>curing=>B-side wave soldering=>cleaning=>testing=>repair) This process is suitable for reflow soldering on the A-side and wave soldering on the B-side of PCB. When only SOT or SOIC (28) pins are present in SMD assembled on the B-side of PCB, this process should be adopted. 3, Single sided mixing process: Incoming inspection=>PCB A-side silk screen printing solder paste (dot patch adhesive)=>SMT=>drying (curing)=>reflow soldering=>cleaning=>plug-in=>wave soldering=>cleaning=>testing=>rework 4. Double sided mixing process: A: Incoming inspection=>PCB B-side dot patch adhesive=>SMT=>curing=>flipping=>PCB A-side plug-in=>wave soldering=>cleaning=>testing=>rework, suitable for situations where there are more SMD components than separated components. B: Incoming inspection=>PCB A-side plug-in (pin bending)=>flipping=>PCB B-side dot patch adhesive=>SMT=>curing=>Flip board=>Wave soldering=>Cleaning=>Testing=>Repair by inserting before pasting, suitable for situations where there are more separated components than SMD components. C: Incoming inspection=>Screen printing solder paste on the A-side of PCB=>SMT=>Drying=>Reflow soldering=>Plug in, pin bending=>Flip board=> The B-side of the PCB is coated with adhesive=>SMT=>curing=>flipping=>wave soldering=>cleaning=>testing=>repairing A-side mixed assembly, B-side mounting. D: Incoming inspection=>PCB B-side spot adhesive=>SMT=>curing=>flipping=>PCB A-side silk screen solder paste=>SMT=>A-side reflow soldering=>plug-in=>B-side wave soldering=>cleaning=>testing=>rework A-side mixed assembly, B-side mounting. First, apply two side SMD, reflow soldering, then insert and wave soldering. E: incoming inspection=>PCB B-side silk screen solder paste (dot patch adhesive)=>SMT=>drying (curing)=>reflow soldering=>flipping=>PCB A-side silk screen solder paste=>SMT=>drying=reflow soldering 1 (partial soldering can be used)=>plug-in=>wave soldering 2 (if there are few inserted components, manual soldering can be used)=>cleaning=>testing=>repairing A-side mounting and B-side mixing. 5, Double sided assembly process A: incoming material inspection, screen printing solder paste (dot patch adhesive) on the A-side of PCB, patching, drying (curing), A-side reflow soldering, cleaning, flipping; Пельянская паяльная паяная пая (точечный клей), монтаж, сушка, паялка для выбоя (* хорошо только для b - сторона, очистка, тестирование, ремонт) с обеих сторон печатной платы. Этот процесс подходит для использования, когда более крупные SMD, такие как PLCC, установлены по обе стороны печатной платы. B: Инспекция входящего материала, PCB A - боковая шелковая печать паяла (точечный патч -клей), исправление, сушка (отверстие), - боковой паяль, очистка, переворачивающая плата; Этот процесс подходит для пайки для рефиша и пайки волны на стороне a - и B - стороной печатной платы, включая клей, монтаж, отверстие, b - боковые волновые пайки, чистка, тестирование и ремонт. Когда в SMD есть только SOT или SOIC (28) PIN