Common Issues in FPC Printed Circuit Boards

• Small Air Bubbles Between Wire Frames

  The presence of small air bubbles between wire frames in FPC printed circuit boards can be attributed to narrow wire frame spacing and excessive wire frame height during screen printing. This results in the inability of solder mask material to be properly printed on the board, leading to trapped gas or moisture. To address this, ensure the solder mask material is fully printed on the board and control the electroplating process carefully.

• Solder Mask Issues in Holes

  Improper screen printing can cause solder mask ink to accumulate in holes due to delayed printing or low screen mesh. Using high mesh screens and high-viscosity printing materials can help prevent this issue. Adjusting the screen printing angle of the squeegee can also improve the printing quality.

• Skip Printing Problems

  Excessive electroplating current and thick coatings can lead to skip printing on FPC printed circuit boards. It is crucial to manage the electroplating process carefully and ensure there are no gaps in the squeegee. Additionally, inspecting for blackening signs on the copper foil wire frame can help identify potential issues.

• Pinholes in Patterns

  Pinholes in patterns can occur when there is debris on the photographing base plate, obstructing light exposure during the imaging process. Regularly checking the cleanliness of the base plate throughout the exposure process can help prevent the formation of pinholes.