In the manufacturing process of printed circuit boards (PCBs), the lamination process of multilayer boards is crucial. As a key step in connecting the circuits of each layer, the quality of lamination directly determines the reliability, stability, and electrical performance of the final product. During this process, the press pad/cushion pad plays an indispensable role, as it not only affects the uniform distribution of pressure and temperature but also directly influences the flatness and interlayer bonding strength of the PCB.

In the lamination process of PCB manufacturing, it mainly involves the stacking structure of copper foil, semi cured sheet (PP), and substrate. In high temperature and high pressure environments, these materials must be firmly bonded to form a complete multi-layer PCB. Buffer pads play the following key roles in this process:

Uniform pressure distribution: During the PCB pressing process, if the pressure distribution is uneven, it can easily lead to local stress concentration, resulting in board warping, interlayer peeling, or internal voids. Buffer pads can effectively disperse pressure, ensure uniform force distribution in various areas of the PCB, and improve lamination quality. Optimize heat conduction: The buffer pad has good thermal conductivity, which can evenly distribute heat throughout the entire lamination area, ensuring sufficient resin flow and curing, and avoiding lamination defects caused by local high or low temperatures.

Reduce board deformation: Due to the high temperature and pressure involved in the PCB lamination process, the material may undergo thermal expansion or contraction. Buffer pads can effectively alleviate this thermal stress, keeping the PCB flat after cooling and reducing warping and deformation. Preventing damage to the outer copper foil: During the lamination process, the surface of the copper foil is prone to deformation or even breakage due to direct force. Buffer pads can form a protective effect on the outer layer, preventing damage to the copper foil and improving the electrical performance and appearance quality of the finished product.

The performance of the cushion directly affects the quality of the laminating process. When selecting and using it, the following factors need to be focused on:

High temperature resistance: The hot pressing temperature is generally between 180 ° C and 250 ° C. The buffer pad must be able to withstand high temperatures without deformation or degradation, otherwise it will affect the lamination stability.

Pressure dispersion ability: The elasticity and resilience of the cushion determine whether it can evenly distribute pressure and avoid local stress concentration after being compressed. High quality cushioning pads should have good pressure resistance to meet the requirements of PCB lamination with different thicknesses.

Thermal conductivity: Thermal conductivity can affect the flow and curing speed of resin. If the heat transfer of the buffer pad is uneven, it may lead to different degrees of curing in different areas of the PCB, affecting the interlayer bonding force.

Durability and Cost: Reusable cushioning pads (such as silicone pads and graphite pads) may have higher costs, but they have better long-term economy in high-end PCB manufacturing. Disposable cushioning pads (such as paper cushioning pads), although inexpensive, may incur additional replacement and storage costs.

As a key auxiliary material in PCB manufacturing process, buffer pads play an irreplaceable role in improving lamination quality, reducing defects, and optimizing production stability. Choosing the appropriate cushioning material correctly and optimizing it according to different PCB process requirements is the key to ensuring high-quality, multi-layer, and high-density PCB production. With the advancement of electronic manufacturing technology, buffer pad technology will develop towards higher performance, environmental friendliness, and intelligence in the future, driving the PCB manufacturing industry towards a higher level.