Controlled Flow Composite
Partially cured epoxy-glass bonding sheets formulated with high viscosity prevent the resin from running into cutouts and onto flexible regions during lamination. Utilizing no flow prepreg ensures that the resin stays where it is placed during the lamination of rigid-flex boards. This material is designed to fill the spaces around rigid cores without spilling over the boundary line of the flexible sections.
Proper selection of this adhesive is necessary for maintaining the flexibility of the circuit.
Rigid Flex Assembly
Standard prepreg materials flow too easily under heat and pressure, which can ruin the flex area of a circuit board. Selecting no flow prepreg prevents this squeezeout from contaminating the active bending zones. This ensures the mechanical performance of the flex circuit is not compromised.
Manufacturing Parameter Control
Precise temperature and pressure profiles during the press cycle must be maintained to match the limited flow characteristics of the resin. When using no flow prepreg, the lamination machine operates under narrower tolerances than are required for standard glass-epoxy layups. This control prevents the formation of voids while ensuring the resin does not overflow the critical layout boundaries.
The resulting assembly exhibits flat, clean rigid-to-flex transitions that are free from excess cured resin.
