In surface mount technology (SMT) assembly, there are various factors that can impact the final quality, such as the quality of surface mount components, the quality of PCB pads, solder paste, solder paste printing, placement accuracy of SMT machines, and the temperature profile of reflow soldering. Among these, an essential step in SMT assembly is the solder paste printing on PCB boards. Here are the methods of PCB solder paste printing:
- Manual Solder Paste Printing Machine:
- Secure the stencil accurately onto the printing machine according to the product model, ensuring compatibility between the stencil and the product.
- Place the appropriate amount of solder paste onto the stencil, ensuring that the solder paste is stored in a low-temperature environment.
- Place the PCB board accurately onto the solder paste printing machine, and use a specialized tool for paste application to print the solder paste onto the PCB board.
- Inspect the solder paste on the PCB board for uniformity. If there are areas with excessive or insufficient solder paste, remove the paste with a towel or cloth, and then reprint. Qualified boards proceed to the next process.
- Automatic Solder Paste Printing Machine:
- Secure the stencil accurately onto the printing machine according to the product model, adjusting the height as necessary, and ensuring compatibility between the stencil and the product.
- Place the appropriate amount of solder paste onto the stencil, ensuring that the solder paste is stored in a low-temperature environment.
- Place the PCB board accurately onto the solder paste printing machine, and lightly press the start button to print the solder paste onto the PCB.
- Inspect the solder paste on the PCB board for uniformity. If there are areas with excessive or insufficient solder paste, remove the paste with a towel or cloth, and then reprint. Qualified boards proceed to the next process.
Common considerations include:
- Store solder paste in a low-temperature environment and return it immediately after use.
- Clean the stencil immediately after use to prevent damage. A professional stencil cleaning machine like DEZ-C730 can be used.
- When operating the automatic solder paste printing machine, avoid placing hands under the stencil.
