We can’t deny that flexible PCBs are a suitable circuitry solution for most devices. Their flexibility, design, and assembly are the foremost factors that make them reliable and durable. Yet, what other factors determine the suitability of flexible PCB? Another crucial factor is the right choice of material for the PCBs to enhance performance.
Therefore, this article highlights the different materials you can select for your PCB with the reasons for choosing them. We will also discuss the factors that you should consider before choosing a suitable material for your PCB.
So, keep reading to learn more about your concerns regarding the topic.
Components of Flexible PCB
There are different types of PCBs: rigid, flex, and rigid-flex PCB, having similarities and differences. The manufacturing of flexible PCBs is slightly different from traditional rigid PCBs. Also note that you can find single, double, or multiple layered flexible PCBs and choose according to your need. The single-layer flexible PCB includes the following elements:
- Substrate Base
It is normally dielectric and uses non-conductive materials like polyimide, PEEK, and PTFE. However, the manufacturers generally prefer PI as a dielectric substrate base for their flexible PCBs, owing to its strong resistance to heat.
The electric conductors are spread throughout to make the traces and pads on flexible PCBs pass the current. These are generally of copper because of its conducting nature.
Most manufacturers now avoid using adhesives like epoxy or polyethylene. Yet, it is part of the PCBs as a circuit connector.
The last element is the cover laying of the flexible PCBs. It’s only a thin film-like protective layer for additional resistance and final finishing.
Perks of having Flexible PCB
The popularity of Flexible PCBs has us thinking about the several advantages it offers to users. It is generally because tech advancement calls for flexibility without compromising quality. Their small size, compact fitness, and lightweight make them outshine the traditional rigid PCBs. The bending and twisting nature allows them to fit in the narrow spaces provided by smartphones, wearable gadgets, and other small devices. The flexible PCBs reduce the stress of choosing a suitable fit for your device.
For good measure, these are also light in weight, so they don’t add weight to the device. These are also slightly more cost-effective than other PCBs, owing to the use of material and assembling techniques. More to this, although flexible PCBs are thinner, small, and light than rigid PCBs, they have stronger EMI and resistance to environmental and electrical shocks. The rationale is the thin overlaying doesn’t produce much stress on the electrical components. Plus, it lowers the wiring incorporation to around 60%, so reduces human error; improves the integration.
The most common Substrate Materials for Flexible PCB:
The materials of flexible printed circuit boards are different from the rigid PCBs because of the difference in design and assembly. The manufacturers employ the material that ensures flexibility and optimum performance, irrespective of the provided space and conditions. Following are the types of materials that the manufacturers generally use in the flexible PCBs:
You should consult renowned companies for the more effective suggestion. Yet, if you need our recommendation, we will strongly suggest Polyimide as the right choice of material for your standard flexible PCBs. It presents a dual package of credibility, affordability, and performance. It also offers substantial chemical and thermal protection. Plus, it offers specific features like reduced humidity absorption and enhanced tear strength over other materials, so most people prefer this material for their PCB for their various industrial equipment. One of the reasons is their impressive thermal resistance. So, if, for instance, you use CCL as a cladding component and Polyimide as a substrate material, it works wonders as it doesn’t let the CCL get soft if faced with high temperatures. It ensures that the PCB stays elastic and flexible for a long time. So, the manufacturers mostly use polyimide material with CCL or copper-clad laminate in PCB for mobile phones, tablets, smartwatches, mini cameras, and small calculators.
This material is also shortly known as PTFE. If you require the PCB to sustain high temperatures and low dissipation, choose PTFE. Besides, it offers strong stability to the devices. You can generally find this material in the machinery of automotive companies or aerospace equipment. You can also use this PCB material for devices designed for driving guidance, antennas, and telemetry guiding applications. Likewise, you can also find it on non-stick crockery.
- Polyether ether Ketone
Another PCB material is Polyether ether Ketone or PEEK. It makes the suitable substrate base for the PCB if you need radiation and chemical resistance. For good measure, it can also sustain extensive thermal temperatures without melting as its minimum temperature is high, ensuring reliable and durable performance. You can find this material in the flexible PCBs employed in medical equipment like X-ray machines that are prone to radiation.
Conducive PCB materials
If you want to experiment with PCB material, you can consider the conducive flexible PCB material according to your system requirements. Copper comes to our minds immediately when we discuss the conducive materials. There are two types of copper material: rolled and annealed and electro-deposit. The RA copper foil offers a flat array-shaped layer, while ED provides tough but smooth fish-scale copper foil. Rolled and annealed copper material is suitable for greater flexibility. So, manufacturers who need high-density flexible PCBs opt for electro-deposit copper material.
Yet, the manufacturers also use aluminum, gold, nickel, and silver as conducive flexible PCB materials. Many also employ photosensitive polyimide material as a conducive substrate for the PCB if they demand a more dense and stable PCB.
Go Halogen-free with Liquid Crystal Polymer
Although Polyimide offers a long list of advantages and most manufacturers prefer it over others, it has some cons also. Liquid crystal polymer serves as a substitute substrate material for the flexible PCB. The European Union has significantly taken this step of banning the polyimide substrate due to environmental conditions. Industries now prefer well-functioned and eco-friendly PCB materials to tackle growing climate change. The plus point is Liquid crystal Polymer is renewable. So the manufacturers can use it more than once. It is halogen-free, so it is safe for the atmosphere and equally efficient in performance.
Factors to consider before choosing flexible PCB material
- Performance Level
It should be the foremost priority when choosing the material for flexible PCBs. We can’t compromise on the functionality of our system after paying bucks. Choose the material that suits your device’s needs to let it function efficiently.
- The right fit
If you want a flexible PCB, you must have a restrained space. So, ensure that the material offers enough bending and flexibility to perfectly fit in the provided space of your device. Here, perfect fit doesn’t imply dimensions, but bending nature.
Cost also becomes a vital aspect of performance and fitting. It is a treat to find the material for flexible PCB that’s both efficient and cost-effective, making it an all-in-one package.
The weight of the PCB matters for the manufacturers designing equipment that can’t carry weight like satellites. Ensure that you choose the material for your flexible PCBs that doesn’t add much to its weight.
- Required protection
It is significant to choose the material considering their aspects. The two things that affect the PCB the most: thermal and chemical energy. Ensure what your system needs and choose accordingly. If you need chemical and radiation protection, polyether ether ketone is best. However, Polyimide is best for strong thermal protection that offers a 3.6 dielectric constant.
- LED lighting
LED lights generate heat when functioning. So, the manufacturers employ metallic base materials like aluminum, silver, or copper. These conducive substrate materials restrict the heat generation from getting stuck and heating the PCB, enhancing the lightning. It enables heat dissipation. So the components don’t melt or soften at high temperatures. Remember that conducive or metal substrate materials are used for flexible PCBs, having LED lights to enhance their performance.
The material plays a significant role in determining the performance and capability of the flexible PCB. So, it is crucial to choose the right material for your PCBs to ensure optimal functionality. Above all, no one wants to waste their bucks on PCBs that don’t meet their needs. Yet, this search requires a comprehensive analysis of the application’s needs, so you can choose the flexible PCB that suits your system. We humbly suggest you ensure the durability, flexibility, and quality of the flexible PCB material before buying one.
Above all, after considering the suitable PCB material, you should look for the manufacturers that offer you qualitative flexible PCBs as it makes the final step of the design. Anyway, who doesn’t want to avail of suitable solutions, all at an affordable cost without compromising the quality?
Hopefully, it will help you in deciding what suits you best. Yet, if you are confused, you can consult an experienced manufacturer for your flexible PCBs to get what you want.