Introduction: This article presents a comparative analysis of different conductive hole plugging processes for surface mount boards, particularly focusing on the challenges and requirements associated with achieving customer satisfaction.
Process 1: Plug hole process after hot air leveling

• Process flow: board surface solder mask → hot air leveling → plug hole → curing
• Description: Using aluminum or ink blocking screen to complete via hole plugging post hot air leveling, with plugging ink as photosensitive or thermosetting. Ensures no oil leakage post hot air leveling, but may lead to uneven surface contamination and potential issues with virtual soldering during BGA mounting.
  Process 2: Plug hole process before hot air leveling
• Process flow: pretreatment → plug hole → grinding plate → pattern transfer → etching → board surface solder mask
• Description: Utilizing CNC drilling to drill aluminum sheets, followed by screen plating and hole plugging to ensure flat via holes. This process demands one-time thickening of copper and high-performance grinding equipment, making it less commonly used in PCB factories.
  Summary: The utilization of the plug hole process after hot air leveling addresses concerns of oil leakage but poses challenges related to surface contamination and uneven plugging. On the other hand, the plug hole process before hot air leveling ensures flat via holes but requires stringent copper plating and high-performance grinding equipment. Each process has its advantages and disadvantages, necessitating careful consideration of the specific requirements and production capabilities.