Due to the rapid development of electronic technology, printed circuit technology has also seen continuous advancements. PCB boards have evolved from single-sided and double-sided to multi-layered boards, with the proportion of multi-layer boards increasing annually. The performance of multi-layer boards is progressing towards high precision, density, fine details, and varying sizes. A crucial step in the manufacturing of multi-layer boards is the lamination process, making the control of lamination quality increasingly important. Therefore, a thorough understanding of the multi-layer board lamination process is essential to ensure high-quality lamination. After years of lamination practice, the following process technology recommendations have been summarized to enhance the quality of multi-layer board lamination.
A. Designing the inner core board to meet lamination requirements:
With the advancement of laminating machine technology, heat presses have evolved from non-vacuum to vacuum heat presses. The heat press process occurs in a closed, invisible system, making it imperative to appropriately design the inner layer board before lamination. Here are some essential considerations:
1. Choose the core board thickness based on the total multi-layer board thickness ensuring uniform thickness with minimal deviation. Particularly for multi-layer boards with more than 6 layers, ensure consistency in the latitude and longitude directions of each inner core board to prevent unnecessary bending.
2. Maintain a significant distance between the core board’s outer dimensions and the effective unit, minimizing material wastage. For instance, a four-layer board should have a spacing greater than 10mm, increasing to 15mm for a six-layer board, and even more for higher layer numbers.
3. Design positioning holes to minimize layer deviation in multi-layer boards. For a four-layer board, include at least 3 positioning holes for drilling. For boards with more than 6 layers, add over 5 layer-to-layer overlapping positioning rivet holes and tool plate positioning holes for rivets. The number and positioning of these holes should correspond to the board’s layer count, placed as close to the edge as possible for improved alignment and production efficiency. Design the holes in a shape suitable for automatic identification by the shooting machine, typically a complete or concentric circle.
4. Ensure the inner core board is free of openings, shorts, open circuits, oxidation, cleaning surface, and residual film.
A. Designing the inner core board to meet lamination requirements:
With the advancement of laminating machine technology, heat presses have evolved from non-vacuum to vacuum heat presses. The heat press process occurs in a closed, invisible system, making it imperative to appropriately design the inner layer board before lamination. Here are some essential considerations:
1. Choose the core board thickness based on the total multi-layer board thickness ensuring uniform thickness with minimal deviation. Particularly for multi-layer boards with more than 6 layers, ensure consistency in the latitude and longitude directions of each inner core board to prevent unnecessary bending.
2. Maintain a significant distance between the core board’s outer dimensions and the effective unit, minimizing material wastage. For instance, a four-layer board should have a spacing greater than 10mm, increasing to 15mm for a six-layer board, and even more for higher layer numbers.
3. Design positioning holes to minimize layer deviation in multi-layer boards. For a four-layer board, include at least 3 positioning holes for drilling. For boards with more than 6 layers, add over 5 layer-to-layer overlapping positioning rivet holes and tool plate positioning holes for rivets. The number and positioning of these holes should correspond to the board’s layer count, placed as close to the edge as possible for improved alignment and production efficiency. Design the holes in a shape suitable for automatic identification by the shooting machine, typically a complete or concentric circle.
4. Ensure the inner core board is free of openings, shorts, open circuits, oxidation, cleaning surface, and residual film.
