Processus de production 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=>Réparation d'un montage latéral - et b - mélange latéral . 5, processus d'assemblage à double face A: inspection des matériaux entrants, pâte de soudure d'impression à l'écran (Patch adhésif) sur le côté A - de PCB, séchage, séchage), un - retourner; Écran d'impression de pâte de soudure (adhésif du patch de points), montage, séchage, soudure de reflux (* bon uniquement pour b -, nettoyage, test, réparation) des deux côtés du PCB. Ce processus convient à une utilisation lorsque des SMD plus grands tels que PLCC sont montés des deux côtés du PCB. B: inspection des matériaux entrants, PCB A - Pâte de soudure d'impression de la soie (adhésif de patch à points), patch, séchage (durcissement), a - Soudeur de reflux latéral, nettoyage, carton de retournement; Ce processus convient au soudage de reflux et à la soudure d'onde du côté A - et b - d'un PCB, y compris l'adhésif, le montage, le durcissement, B - Soudeur d'onde latérale, le nettoyage, les tests et la réparation. Lorsque seules des broches SOT ou SOIC (28) sont présentes dans SMD assemblé sur le côté b - du PCB, ce processus doit être adopté