Comparative Analysis of Conductive Hole Plugging Processes for Surface Mount Boards
Process 1: Plug Hole Process After Hot Air Leveling
- Process Flow: board surface solder mask → hot air leveling → plug hole → curing
- Description: This process involves using aluminum or ink blocking screen to plug via holes after hot air leveling. The plugging ink used can be photosensitive or thermosetting. While it prevents oil leakage post hot air leveling, it may result in surface contamination and potential issues 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: This method utilizes CNC drilling on aluminum sheets, followed by screen plating and hole plugging to ensure flat via holes. It requires thickening of copper and high-performance grinding equipment, making it less common in PCB factories.
Summary: The plug hole process after hot air leveling addresses concerns of oil leakage but may lead to surface contamination and uneven plugging. On the other hand, the plug hole process before hot air leveling ensures flat via holes but demands stringent copper plating and high-performance grinding equipment. Each approach has its pros and cons, so it’s crucial to consider specific requirements and production capabilities when choosing the right method.
