Commom Quality Issues of SMT Processing and Solutions
Publish Date:2017-12-29 18:38:34
Clicks: 330
| Quality Issues | Solutions | |
Gluing Process | Gluing wire/spillover | Revise the gluing process parameters; Control the amount of gluing; Adjust the process parameters of SMT patch; |
| Plugging of glue mouth | ||
| Empty gluing | ||
| Components displacement | ||
| Components lost after waving soldering | ||
| Fixed components pins are flost or shift | ||
SMT Soldering Quality Defective | Tombstone | Change the pad design and layout. |
| Select higher activity of solder paste;improve the solder paste printing parameters,especially the hole size of the stencil | ||
| Adjust the processing parameters of the SMT Machine | ||
| Adjust the approprite temperature curve according to each different product | ||
| Solder Joint | Attention to the heating rate and take a moderate preheat and provide a good platform to make the most of the solvent volatilization | |
| Flying solder joint | Select the high quality solder paste, and pay attention to the storage and use of solder paste | |
| Solder Bridge | Adjust the proportioning of solder paste or use a good quality solder paste | |
| Printing machine has poor repeatability and uneven alignment | Adjust the printing press and improve the coating layer of PCB welding disk | |
Wave Soldering Quality Defective | Solder icicle | Adjust the transmission speed to the right place, adjust the preheating and tin pot temperature, revise the PCB transmission angle, optimize the nozzle, regulate the wave shape, change the next flux and solve the weldability problem of the lead |
| Solder short | Solve the weldability of the lead, adjust the preheating temperature, test the tin and impurity content of solder, revise the flux density, reduce the hole of the pad, eliminate the oxide of PCB, clean the panel, adjust the transmission speed and adjust the temperature of the tin pot | |
| Insufficient solder | Solve the weldability of the lead, reduce the pads and pads holes in the design, reduce the welding angle, adjust the transmission speed,the tin pot temperature, check the pre coating flux device and test the solder content. | |
| Missing solder | Solve the weldability of the lead, check the wave crest device, replace the flux, check the pre coating flux device, solve the PCB solderability (cleaning or return), check and adjust the transmission device, use the flux together, and adjust the technological process. | |
| Blistering of solder film after welding | Strictly control of each production link, the purchased PCB should be checked before sending to storage, usually PCB in the temperature of 260℃ should not appear in the 10s bubble phenomenon | |
| PCB should be stored in a ventilated and dry environment with a storage period of not more than 6 months. | ||
| PCB should be pre-baked in a oven at 120℃ for 4 hours before welding | ||
| The preheating temperature in wave soldering shall be strictly controlled, and it should reach 100~140 degrees before the wave soldering. If the water containing flux is used, the preheating temperature should reach 110~145 degrees. |
