Flexible Printed Circuit Manufacturers Handle Custom Orders
The fabrication of flexible printed circuit boards (FPBs) involves a lot of different steps. It is not a job for just any manufacturer, as they must be equipped with a team of highly skilled technicians to handle the challenges involved in producing high-quality flex PCBs. A reputable flexible PCB manufacturer will have a well-documented process and strict quality standards to ensure that their boards are of top-quality. They must also be able to meet their client’s deadlines and budgetary requirements.
Generally, the fabrication of a flex circuit begins with preparing the substrate materials. This includes cleaning and etching the surface to make it ready for the circuit patterns. Next, a photoresist material is applied to the substrate. A UV light is then used to expose the photoresist pattern to the substrate. This is known as photolithography. Once the pattern is transferred, etching removes the unwanted copper from the substrate, leaving behind the desired circuit pattern. The final step is applying a solder mask and surface finish, such as ENIG (Electroless Nickel Immersion Gold), to protect the copper circuits from oxidation and provide a good surface for soldering components.
Some flexible printed circuit manufacturers include a layer of insulating polyimide (PI) material in addition to the layers of copper. These insulating layers add to the ductility of the board and allow it to bend many times without damaging the circuits. Some flex circuits can even withstand 200,000 bend cycles!
How Flexible Printed Circuit Manufacturers Handle Custom Orders
In addition to insulating layers, a flex circuit may have one or more copper foil layers. These copper layers contain the circuit traces and pads. The flex circuit’s design often requires vias, or laser-drilled holes, to connect the copper layers together. These vias are then plated through to make them conductive. Using Microvias instead of blind and buried vias can help keep the thickness of the copper circuit layer low, which is especially important for flex circuits.
The flex circuit’s design may also require overlays, which are either acrylic or polyester covers that allow the user to interact with the PCB in certain ways. Some common overlays include LEDs, LCDs and switches. The overlays may be attached to the flex circuit with an adhesive or through a hot bar solder connection, which eliminates the need for a connector between hardboard and flex circuit.
A stiffener is a rigid material that attaches to the flexible PCB to provide support and prevent it from bending or flexing beyond its design limits. It can be made from a variety of materials, including FR4. Stiffeners also help with component attachment and handling.
A reputable flexible PCB manufacturer will provide their clients with a prototype before mass production. This will allow them to spot any errors in the design before they begin production. This will save time and money. Additionally, it will ensure that the final product is of top-quality and will be able to perform as intended.