Flex PCB & its Types
A flex PCB, FPCB or flexible printed circuit board, is a type of circuit board that is made with a flexible material, usually a polymer or flexible composite. These circuit boards are designed to be bendable and flexible, which makes them ideal for use in applications where traditional rigid PCBs would be too stiff or inflexible. Flex PCBs are commonly used in a variety of industries, including consumer electronics, automotive, medical, and military, among others. Some common applications for flex PCBs include wearable devices, mobile phones, and smart watches. They are also used in applications where space is limited or where the circuit board needs to be able to move or flex, such as in electronic door locks or automotive components. Flex PCBs are typically made by etching copper onto a flexible substrate, and then adding layers of insulation and other components as needed. They are then tested and inspected to ensure they meet industry standards and specifications.
This article is all about flex PCB, its major types, manufacturing process and their advantages of use. ELE PCB is a leading manufacturer of Flex PCB and other types of PCB, and we aim to get you familiar with flex PCB before ordering your PCB.
Table of Contents
1. What Is a Flex PCB?
The IPC defines a flexible printed circuit as “a patterned arrangement of printed circuitry and components that utilizes flexible base material with or without flexible cover lay.” This definition, while basically, illustrates what you can expect from a flex PCB which is a bendable printed circuit that is made of a flexible film.
A flexible printed circuit consists of a metallic layer of traces, usually copper, bonded to a dielectric layer, usually polyimide. Thickness of the metal layer can be very thin (<. 0001″) to very thick (> . 010″) and the dielectric thickness can widely vary. Flex PCBs, however, have become far more complex over the years as they have been applied to industries across the board.
1.1 Applications of Flex PCB
In many applications, flexible PCBs can eliminate the need (and cost) of connectors and cables, improving connection reliability and reducing assembly time, assembly costs and overall device dimensions.
Flex PCBs are important in a variety of applications because of their unique properties and capabilities. Some of following applications of Flex PCB explain why these are important.
- Wearable Devices: Flex PCBs are essential for the design and production of wearable devices, such as smart watches and fitness trackers, as they allow for a slim, flexible, and durable design.
- Mobile Phones: Flex PCBs are used in many mobile phones to allow for folding and bending, as well as to save space and reduce weight.
- Automotive: Flex PCBs are used in a variety of automotive applications, such as electronic door locks, airbag systems, and fuel systems, to allow for flexibility and durability in harsh environments.
- Medical Devices: Flex PCBs are used in medical devices, such as catheters and endoscopes, to allow for flexibility and ease of use in the body.
- Military: Flex PCBs are used in military applications, such as communication and navigation systems, to allow for durability and flexibility in extreme environments.
- Consumer Electronics: Flex PCBs are used in many consumer electronics, such as laptops and game controllers, to save space and improve performance.
- Industrial: Flex PCBs are used in industrial applications, such as robotics and automation systems, to allow for flexibility and durability in demanding environments.
- FPC Antenna: By converting electric signals into electromagnetic waves, PCB antennas can facilitate long-range communication for devices operating at high frequencies.
2. Types Of Flex PCB
ELE PCB is the industry’s foremost flexible PCB provider, and as such, they are able to provide you with some of the most reliable flexible circuit designs available. Flex circuits come in a wide variety of forms, ranging from single to multi-layer alternatives and even more rigid design configurations in some cases. The most important flexible circuit possibilities are discussed in the following summary.
2.1 Single-Sided Flex PCB
This configuration has a single layer of conductive copper that may either be connected between two layers of insulation or constructed with one layer of polyimide insulation and an exposed side. Both configurations are possible. A chemical etching technique is subsequently used to the inside copper layer, which results in the production of the circuit design. Components, connections, pins, and stiffeners may all be included onto a single-sided flexible printed circuit board thanks to the layout’s accommodating architecture.
2.2 Double-Sided Flex PCB
A double-sided flex PCB is constructed with two conducting layers and an insulating layer made of polyimide in between them. It is possible for the exterior surfaces of the conductive layer to either be uncovered or have coverings, such as a copper pad. Plated through-holes are the most common way for connecting layers, although alternative approaches are also possible. Double-sided flex PCBs, just like single-sided flexible circuits, have the ability to support extra elements including pins, connections, and stiffeners.
2.3 Multi-Layered Flex PCB
The multi-layered flex PCBs are an advancement that goes beyond the single-sided and double-sided flex circuits. These circuits integrate a number of single-sided and double-sided circuits, and they accomplish it by linking three or more flexible conducting layers with insulating layers in between each one. The outer layers of these units often have coverings, and flexible circuits typically feature a through-hole that is copper-plated and spans the length of the full thickness of the circuit. The most effective way to circumvent restrictions pertaining to crossovers, crosstalk, impedance, and shielding may be accomplished by utilizing multi-layered flexible circuits.
2.4 Rigid-Flex PCB
Although rigid-flex PCBs have a somewhat different layout from the ones described above and often cost more than other flexible PCB alternatives, they accomplish the same goals as the vast majority of other types of PCBs. These models often make use of two or more conducting layers, although the insulating material that surrounds each conductive element can be either stiff or flexible, depending on the application. They vary from multi-layered circuits in that they have conductors on rigid layers, which gives them higher strength than comparable units that just rely on stiffeners for support. Because of this, rigid-flex PCBs have become particularly attractive in the aerospace and military industries.
2.5 Aluminum Flex PCB
PCBs made of flex aluminium are best suited for high-powered businesses like the medical and automotive sectors, in addition to other sectors that need significant power and lighting consumption. Because of their tight and compact shape, they may also readily fit into extremely small areas. Their layers of aluminium give them the important property of being able to transport heat, and in addition to that, they are lightweight, sturdy, and cost-effective.
2.6 HDI Flex PCB
One of the technologies in the PCB market that is expanding at the quickest rate is included on high-density interconnector, or HDI, boards. Because they feature a higher wire density than standard circuit boards, they are able to improve electrical performance and speed while simultaneously lowering the weight and size of the equipment. They work wonderfully for consumer goods such as laptops, mobile phones, and video gaming consoles.
2.6 HDI Flex PCB
One of the technologies in the PCB market that is expanding at the quickest rate is included on high-density interconnector, or HDI, boards. Because they feature a higher wire density than standard circuit boards, they are able to improve electrical performance and speed while simultaneously lowering the weight and size of the equipment. They work wonderfully for consumer goods such as laptops, mobile phones, and video gaming consoles.
2.7 Ultra-Thin Flex PCB
The board characteristics and materials used in ultra-thin flex PCBs are very tiny and very thin. They are an excellent choice for use in applications that need extremely lightweight circuit boards, such as those found in implanted medical devices and portable electronic equipment.
As can be shown, the use of flex PCBs is not restricted to designs employing a single layer. In comparison to standard FR4 circuit board designs, ELE PCB’s ability to manufacture double-sided and even multi-layered flexible PCBs for your more complicated layouts gives you access to a wider variety of connection options. Get in touch with us so that we can put you in touch with a Customer Concierge who can advise you on the kind of design that will work best for the specific needs of your application.
In conclusion, the circuit connections on flex PCBs are made with the help of a base material that is flexible. Flex circuits come in a wide variety of configurations, ranging from single-sided to double-sided and multi-layer possibilities, and even more stiff designs are a possibility. Because of the longevity and size of flexible printed circuit boards, in addition to the reducing sizes of electronic components, flexible PCBs are being used by an increasing variety of sectors. These industries include LED, medical, power systems, and others.
3. Manufacturing Of Flex PCB
Flex circuits are typically manufactured using a polyimide material and one to multiple layers of copper. Popular suppliers of flexible materials are DuPont and Panasonic (we typically stock both). A flexible printed circuit board material will bend without snapping.
The manufacturing process for flex PCBs typically involves several steps:
3.1 Design
The first step in manufacturing a flex PCB is to create a design for the circuit layout. This involves placing the components on the PCB and routing the traces (conductive pathways) between them. The design is typically created using computer-aided design (CAD) software.
3.2 Photolithography
Once the design is complete, a photolithography process is used to transfer the circuit layout onto a flexible substrate. This involves coating the substrate with a layer of photoresist, which is a light-sensitive material. The design is then printed onto the substrate using a light source, and the photoresist is developed to create a pattern of exposed and unexposed areas.
3.3 Etching
The exposed areas of the substrate are then etched away using a chemical etching process, leaving behind the desired circuit pattern.
3.4 Lamination
The etched substrate is then laminated with additional layers of insulation and conductive material to create the desired number of layers in the flex PCB.
3.5 Drilling
Vias (tiny holes through the PCB) are then drilled through the layers of the PCB using a laser or mechanical drilling process.
3.6 Soldering
The components are then soldered onto the flex PCB using a soldering process such as wave soldering or selective soldering.
3.7 Testing
The flex PCB is then tested to ensure it meets the required specifications and performance criteria.
3.8 Finishing
The flex PCB is then finished with a protective coating or other treatment to improve its durability and lifespan.
4. Advantages Of Flex PCB
Flexible printed circuit boards come with numerous advantages over a rigid PCB. This has made them common in consumer electronics yet comes with some drawbacks. As a result, rigid and flexible PCBs both have their place, and are often used in conjunction with each other in rigid-flex circuits.
- The majority of the benefits that come along with flex PCBs are attributable to the fact that they take up less space and are lighter. In point of fact, switching from a rigid PCB to a flexible printed circuit board (PCB) can result in a reduction of space of more than fifty percent and a decrease of weight of ninety-five percent, all while retaining the functionality and dependability of the circuit.
- They are able to tolerate shifting external stresses and enhance their resistance to shock and vibration thanks to the flexibility, decreased weight, and reduced number of interconnects in the PCB.
- Signals will continue to operate normally regardless of the circumstances outside thanks to the flexibility of flex PCBs, which work in a broad variety of settings. Because of this, the PCB’s signal dependability is improved.
- Because of their thinner flex layers and fewer component components, flex PCBs are able to handle larger circuit densities than traditional PCBs.
- As a result of the thinner flex PCB materials, the ratio of surface area to volume may be increased, which results in improved heat dissipation.
- Flex PCBs are often less expensive than other types of printed circuit boards due to the reduced number of assembly processes required to produce them.
- Wiring faults are significantly decreased on flex PCBs as a result of the removal of mechanical connectors and the reduction in the number of different assembly techniques.
ELE is able to meet all of your flexible PCB and rigid-flex PCB requirements, from the prototype stage all the way through manufacturing. We have a competitive advantage in the printed circuit board business because to our expertise and experience in producing flexible printed circuit boards. In addition, we never guarantee a price that is higher than our competitors and never mandate a minimum quantity of a product that must be purchased with each order.
5. ELE Technology Co. the Leading PCB Manufacturer
Prototyping printed circuit boards (PCBs) is a useful technique for designers since it helps save time and money while guaranteeing a high-quality result. Get in touch with us right away if you need PCB prototype services for an upcoming venture.
Over 6,000 engineers and 200 contract assemblers from across the world rely on ELE PCB for their PCB prototype services. We pride ourselves on our dedication to quality and our ability to consistently provide fully functional prototypes that meet or exceed your requirements. Whether you need a simple two-sided FR4 board or a very complicated multi-layered prototype, our PCB design professionals have you covered. Your prototype may be provided by ELE PCB promptly, proficiently, and cheaply, with no hidden expenses.
Our method is straightforward; we utilize CAD software to plan the layout of the prototype, select the manufacturing material, and then cut and assemble the board. After that, the circuit board is complete and ready for testing. And when the time comes, we’ll assist you in making the jump from prototype to production.
ELE PCB is here to assist you if you’re in the market for professional PCB prototype services. Get in touch with us now and talk to a member of our service team about your PCB prototyping needs and how ELE PCB can fulfill them.
ELE Flex PCB Product Details
| Product name | FPC Board |
| Materials | PI/PET |
| Type | Flex pcb |
| Layers | 1-8L |
| Finished board dimensions | 1500 x 500mm |
| Finished surface | OSP/ENIG |
| Board thickness | 12.5um to 50um |
| Finished board thickness tolerance | ±2 mils |
| Drill hole diameter | 0.15 to 6.7mm |
| Production Needed Files | Gerber files |
| Minimum line space/width | 0.1mm |
| Finished via diameter | 0.1mm (minimum) |
| Inner layer dielectric thickness | 0.0275 to 0.1mm |
| Hole diameter tolerance of PTH | ±2 mils |
| Hole diameter tolerance of NPTH | ±1 mil |
| Hole position tolerance (compared with Gerber data) | ±1 mil |
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