Contents
Designing
The manufacturing process starts with the CAD design as usual, but the designer must take some extra steps to place key components and fragile circuitry away from the stress points.
The flex board design must align the components parallel to the direction of the intended bending position to minimize the stress on the solder joint and copper strip beneath it.
Flex Board Laminate Preparation
After the CAD design, the flex PCB manufacturing heads to copper laminates for the flex board.
A thin layer of heat-resistant polymer or similar material is prepared and cut to the desired shape and size.
The sheet of heat heat-resistant base is coated with a heat-induced adhesive on of sides.
A thin layer of copper sheet is placed over the adhesive layer and heat-pressed for several hours to bond them together.
A second protective layer is usually added to the flex board manufacturing process to strengthen the surface and allow the board to withstand the temperature and stress.
Circuit Etching Process
The PCB design is converted to a graphical image and imposed on the flex board laminate with UV-curable masking paste and a computerized UV exposure.
This step marks the copper for the circuit connection and leaves the unwanted copper exposed.
The sheet is carefully transferred to the chemical treatment bath for etching the excess copper way.
A powerful industrial solvent is used to etch the copper.
The flex board manufacturing includes the number of washes to ensure the elimination of chemical and flux residue.
For the solder mask, unlike traditional methods, the flex pcb manufacturing process covers the entire copper trace with a thin layer of the laminate sheet in which the required holes are pre-pressed.
Assembly and Testing in Flex Board Manufacturing
The next step in flex board manufacturing is silkscreen layer printing, which marks the component’s outline and alignment.
As these flex boards are usually tiny, high-resolution mostly do the assembly.
Some of the complex components are soldered by hand.
The flex PCB manufacturing tests the board in each layer for defects and misalignments.
