Thermal Script
Multi-stage settings for heat, suction and vertical force define the operating conditions of the lamination machinery. Every vacuum press profile includes the specific timings required to remove gas from the stack before the resin starts to melt and fill internal cavities. This plan ensures that the epoxy cures fully without leaving behind stresses that could lead to delamination later in the thermal life of the board.
It specifies exactly when the atmospheric air is removed to prevent the inclusion of humidity and oxygen at the bonding interfaces.
Segment Control
The initial phase holds the boards under a deep vacuum at low temperatures to clear trapped air between the glass fibers. As the heat rises according to the vacuum press profile, the material enters a flow state where it moves into the open areas created by the circuit layout. Force is then increased gradually to compress the sheets together without crushing the delicate glass fabric or pushing the resin out of the edges too quickly.
The hold time at the top temperature usually lasts for ninety minutes to allow the chemical reaction to lock the layers into a permanent lattice.
Stability Limit
Deviation from the established parameters results in boards that display inconsistent thickness or inner-layer bubbles. These failures appear during thermal stress testing where internal gases expand and force the layers apart at high temperatures.
