Before the lamination process of high‑ layer count multi‑layer PCBs, the inner core sheets and prepregs (PP) need to be locally fused together for pre‑fixation. The stacked assembly can then be sent into the hot press together with outer‑layer copper foils for final lamination. Compared with the traditional riveting process, which tends to cause defects such as inner‑layer short‑circuits, uneven stamping pressure, board surface indentation and scratches, the hot‑melt pre‑bonding process effectively eliminates these drawbacks of riveting, and greatly improves production efficiency and product quality.