Flexible printed circuits or flex PCBs are electrical circuits which offers mechanical support to the electrical components that are connected via the conductive copper wires.
Furthermore, it forms the main building block of a good number of electronic projects. In this article, we will be walking you through all you should know regarding the topic.
What are the Materials for the Flex Circuits?
The flexible circuit boards usually come in multi-layered, double-sided or single-sided forms, and each require different materials to help in functioning effectively. RayMing PCB & Assembly only teams up with the branded materials brought from trusted materials. Some of the materials for your flex PCB include
Adhesives: Requirements for a specific application, and the conductor’s dimensions helps you choose the right adhesive. Some well-known adhesives present on the PCB market are epoxies, acrylics, base materials that are adhesive, and adhesives that are pressure sensitive.
Finishes
To meet the project’s requirements, you can select from different finishes. Some of the very few you can select from are HASL, ENIG, Pb-free HASL, immersion tin, and immersion silver, as well as other organic materials. Every option presents different results. Also, it works well for different application. This is why it is advisable to reach out to us to deliver the best possible finish that suits your needs.
Insulators
It is a must to work with insulators. There is a need to work with the most appropriate insulating material which helps in supporting the application of your flexible PCB. Working with a wrong insulator can cause PCB failure later on.
The PCB insulators usually combine with flexible substrates and coverlay materials in different thicknesses and form factors. Some well known insulators are photoimageable coverlays, flexible solder masks, polyethylene naphthalate (PEN), polyester, Polyimides, polyethylene terephthalate (PET), solder masks, and screen printed dielectric insulators.
We advice that you reach out to us to tell the most appropriate material that suits your Printed circuit board needs. Below are a few more options for you to consider ahead of making that call.
Also, the flex circuit market keeps expanding, to include hot bar solder, graphic overlays, panelization, and more.
What are the Applications of the Flex PCB?
The flex PCB is just like the non-flex board. The only thing here is that flexible PCB makes use of a specific flexible base material that helps in making the circuit connections. Now, this move is very helpful especially for those products that may not serve as stationary devices.
Also, the size as well as the durability of flexible PCBs, coupled with electronics’ shrinking sizes has led to their adoption by many industries. A few of these applications and industries are outlined below.
Automobiles
The automotive industry has now turned increasingly towards the electronic components, the circuits, which have the ability to handle stresses and vibrations of the interior of a vehicle play a very important role today. The flexible circuit boards provide a more valuable option to the industry, and still provides a cost-effective and durable option.
Consumer Electronics
The flexible PCB is useful in smaller electronic products such as cameras, tablets, cell phones, video recorders, and more. These set of products are usually handled and transported regularly. This makes the resistance of the flexible PCB strong against vibration and shock a very important feature.
RF, High Speed Digital, &Microwave Applications
Flexible PCBs reliability is great. This usually makes them an ideal option for the handling of high-frequency signals.
LED
LED lighting is very popular today in the commercial and residential applications. Primarily, this is due to the great power efficiency of the LED technology. Usually, heat isn’t the only concern and can be mitigated with the help of the flexible printed circuit boards as well as its great properties for heat transfer
Industrial
Usually, industrial electronics are known to handle large amounts of stress and vibration. Therefore, the flexible PCBs having anti-vibration and shock absorption capabilities are very important.
Medical Systems
The dense and small electronic designs have become very important today in the medical field. In addition, using the surgical and handheld technology as well as electronic implants has become popular. You can apply the flexible PCBs in the two cases. This will meet the size and durability requirements of the surgical technology as well as the necessary flexing capability for the implants.
Power Electronics
This is another advantage of the flexible printed circuit board. You can couple it with very flexible and thin copper layers. This means that the circuit board has the ability to handle power currents that are heavier. Here, this point plays a very important role in any device that needs more power to be able to function at 100% capacity such as those present in our power electronics industry.
What are the Flex PCB Types?
As one of the best suppliers of flexible printed circuit boards, Rayming PCB & Assembly provides customers with some of the best flexible circuit designs. Flex circuits come in eight major types. Below is an overview of the major flexible circuit alternatives.
Single-Sided Flex PCBs
It includes one conductive copper layer which may be bonded in-between both insulation layers or also built using just an insulating layer of polyimide as well as the uncovered side. Furthermore, the copper layer in the interior passes through the process of chemical etching, thereby producing your circuit design.
The design of this flexible printed circuit board helps in supporting the addition of stiffeners, pins, connector, and components.
One-Sided Flex Circuits having Dual Access
There are some one-sided flex PCBs featuring a dual-access design, which permits users to become accessible to the conductive material present from the two sides of the printed circuit. Furthermore, the function of this design needs flexible circuit boards as well as some specialized layers which help in creating access for single copper layers via the base material’s polyimide layer.
Double-Sided Flex Circuits
This type of flexible printed circuit board has two conductive layers and having a polyimide insulation layer between them. Also, the outer sides of the conductive layer could have covers or become exposed just like the copper pad.
Typically, the layers are all connected through the plated through-holes. However, you can make use of other methods. Similar to single-sided flexible circuits, double-sided flexible PCBs also have the ability to support more elements like stiffeners, connectors, and pins.
Multi Layered Flex Circuits
When you go beyond the double-sided flex circuit and single sided flexible circuit are the multi layered flexible PCBs. This type of circuit helps in the combination of the multiple double- and single-sided flex circuit. It connects at least three conductive layers that are flexible with the insulating layers present between each.
These units’ outer layers usually have covers while the through-hole (copper plated) usually runs via the whole thickness of the flexible PCBs. Furthermore, the Multi-layered flexible circuits offer the most appropriate solution to pass through impedance and crosstalk, crossovers, as well as shielding requirements.
For the multi-layered circuits, it comes with many design options. Take for instance, just like FR4, the multi-layered flex boards may be built making use of buried and blind vias.
In addition, the multi layered circuit layers may be laminated continuously for more protection. However, usually this step is skipped once flexibility is the most important.
Rigid-Flexible Circuits
The rigid flex PCBs or rigid circuit boards come with a little different design in contrast to other types already explained. Also, they cost more compared to other options of flexible PCB. However, the option they serve is similar to majority of other printed circuit boards.
Furthermore, these models may make use of at least two conductive layers. However, the insulation material which sandwiches every conductive element could be a flexible or rigid insulation.
Rigid flex PCBs (rigid flex circuit boards) are much different from the multi-layered circuit due to the fact that conductors are present on the rigid layers. This provides the rigid circuit boards with higher strength compared to the similar units, which relies only on the stiffeners. With this feature, the rigid-flex PCBs are now desirable in aerospace and military industries.
Aluminum Flexible Circuits
The flexible aluminum Printed circuit boards are very important for the high-powered industries like automotive and medical industries, coupled ith those requiring lighting usage and substantial power and lighting usage.
Microcircuits
The flexible PCB microcircuits are very important for the small electronic devices. Furthermore, their vibration-resistant and shock-resistant properties make them better choices for the consumer electronics.
HDI Flexible Circuits
The HDI boards feature one of the industry’s fastest-growing technologies. Also, the high density interconnect flex pcbs possess higher wiring densities compared to the conventional printed circuit boards. Therefore they will be able to enhance their speed and electrical performance thereby reducing the size and weight of the equipment.
Ultra-Thin Flexible Circuits
This flexible printed circuit board feature a thin, small board and materials. This flex circuits are great for applications calling for very lightweight boards, like the medical devices (implantable) and portable electronics.
Conclusion
In summary, the significance of the flex pcb cannot be overemphasized. We can see why it comes in so many types and has different applications.
