rigid flex pcb fabrication

Rigid flex is a PCB that features rigid and flexible sections. It’s ideal for high-speed connections and can withstand a wide range of mechanical stresses and environmental conditions. It’s a powerful design technology that’s used in a variety of applications, including smart watches, mobile devices, and industrial electronic equipment. However, it can be challenging to understand the different components, layers, and processes involved in rigid flex fabrication. This guide is intended to help you better understand how these boards are made and the benefits of using them in your designs.

Multilayer rigid-flex PCBs can have anywhere from 2 to 20+ layers, with a mix of both rigid and flexible areas. They can also feature blind and buried vias, as well as via in pad technology. In addition, they can use controlled impedance traces to minimize electrical reflections and interference. This specialized construction makes them an excellent choice for high-speed electronics and IoT wearables.

The standard configuration of a rigid flex pcb fabrication has the conductive copper layer sandwiched between two insulating layers of polyimide and an adhesive on both sides. This is known as a coverlay and is similar to the solder mask layer in traditional multilayer rigid boards. The flex circuit is then bonded to the coverlay with pressure sensitive adhesive, or PSA. This allows the flex circuit to bend in multiple directions and conform to the bending radius of the underlying rigid section.

How many layers does an rigid flex pcb fabrication typically have?

Next, the flex circuit is etched to expose the copper. This can be done by dipping the laminate in an etch bath or spraying it with an etchant solution. Once the etch process is complete, it’s time to drill all of the required holes, pads, and vias. To do this, manufacturers often use precision laser drilling tools, such as Excimer YAG and CO2 lasers.

Once all of the necessary holes are drilled, it’s time to add the conductive elements. Rigid-flex manufacturers usually plate the copper with an anti-corrosion finish to ensure that it will withstand the harsh environments and extreme temperatures found in ruggedized devices. They can also add plated through-holes or pins, also called button plating, to make it easier to mount component parts.

The insulated flex circuits are then laminated to the top and bottom of the rigid-flex board with another layer of prepreg. This creates a solid surface for the assembly of components and connectors. In addition, the insulating layers protect the flex circuits from chemicals and harsh weather.

Once the rigid and flex circuits are assembled, the manufacturer must test them for functionality. They can be tested in a variety of ways, including grid and flying probe tests. Once the rigid-flex PCBs pass these tests, they are ready for use. To ensure that the rigid-flex PCB meets the requirements of your specific application, it’s important to work with a knowledgeable supplier. This supplier can advise you on the best materials, processes, and testing methods to get your product off the ground.