Flexible PCB( FPC): The New Trend in Electronic Design
Abstract: With the constant upgrading of items, conventional printed printed ciruit
board can no more satisfy the demands of the PCB market, so flexible PCBs have been introduced, and
their market demand is expanding. Medical, aerospace and customer electronics use FPCs.Flexible PCBs are
magical circuit card that can bend, cover, and fold flexibly and move in a slim area like a serpent.
Exactly how does it do this? This write-up will reveal the answer to your question.
What is FPC?
Flexible circuit board, additionally called soft boards. There are several insulating substrates for
versatile setting up, such as polyimide (PI), polyester movie (FAMILY PET), aramid fiber paper (Nomex),
and polyvinyl chloride (PVC).
By embedding circuit design on plastic sheets, even more digital parts can be arranged in order on the
circuit board, therefore realizing an flexible circuit board. The birth of flex-PCB breaks through the
typical interconnection technology. It is prominent due to its light-weight, high versatility, thin
density, bendability, and foldability. It is easy to install.
flexible printed circuit appeared in the United States in the 1970s to create space rocket technology.
It is used in several areas because of its excellent residential properties.
Benefits of FPC
1) High Adaptability
This feature enables the circuit board to be curved and folded up openly without damages. It can be set
up in any type of spatial design, relocated, and stretched in a small space. It contributes to SMT
assembly.
2) Lightweight and Slim
It makes the circuit card design much more compact, therefore lowering the item size, minimizing the
item weight, and making it less complicated to carry. It likewise promotes the development of
high-density, high-reliability, and miniaturization of digital items.
If the item requires to consider the area concern, then flexible printed ciruit board are the very best
choice.
3) Boost Design Flexibility
Due to its light-weight, thin thickness, and versatility, there are multiple circuit card design
strategies throughout circuit design. It raises the PCB’s manufacturability, integrity, and
efficiency.
Furthermore, flex pcb also has the advantages of great heat dissipation and solderability, easy setup,
and reduced general expense.
Flexible Circuit Board Classification
1) Single-Sided Flexible Board
Use single-sided PI flexible copper-clad board product. After finishing the circuit, cover it with a
protective movie to create a single conductor circuit board. It has the lowest expense. When the
electrical efficiency demands are low or taking on single-sided electrical wiring, single-sided flexible
boards should be chosen– as an example, printer inkjet cartridges and computer memory.
2) Double-Sided Versatile Board
Use double-sided PI flexible copper-clad laminate product. After finishing the circuit, a layer of
safety movie is covered on both sides to create a dual-conductor circuit board.
3) Multilayer Flexible Board
Multilayer flexible boards stack up three or even more layers of circuit card with each other, forming
metalized holes with drilling and electroplating to form conductive courses between layers. Although the
variety of PCB layers is endless, we must consider component setting up and PCB manufacturability during
PCB layout design.
4) Rigid-Flex PCB
Rigid-flex PCB is a mix of stiff PCB and flex-PCB uniquely piled with each other. It has the advantages
of both inflexible and flexible circuit board (bendability and durable rigidness). Nevertheless, the
cost is greater, so when producing this PCB, you need to take into consideration lowering the number of
layers.
Flexible PCB Manufacturing Refine
The manufacturing process below is for double-layer boards. The difference in between the single-layer
board and the double-layer board process is that single-layer boards do not need boring and
metallization holes.
Cutting: Cut the product right into the required dimension according to the job order
size needs. The key equipment is an automated reducing equipment and a hand-operated cutting device.
Baking: Dry the dampness in the substratum to stay clear of shrinkage, stratification,
and other effects on subsequent production.
Drilling: It refers to drilling openings and vias on the substrate. It prepares for
succeeding procedures or opening metallization. The main gadget is a CNC drilling maker.
Black hole: Via the great void in this step, a layer of conductive carbon powder is
directly transferred on the hole wall PI, changing the standard copper deposition. It plans for copper
plating.
VCP: It’s vertical conveyor plating, which uses copper electroplating to thicken
the hole wall surface and surface copper according to the customer’s demand.
Dry film pre-treatment: Clean the board surface
utilizing chemical cleansing to remove oxidation and surface roughening.
Dry film pasting: A layer of photosensitive dry movie is pasted on the surface of the
copper aluminum foil.
Exposure: According to the movie direct exposure representing the job order, the image
of the circuit pattern movie is transferred to the dry movie. The device is the automated exposure
machine.
Advancement: Use sodium carbonate remedy to liquify the unexposed completely dry movie
to form a completely dry movie pattern.
Etching: The copper aluminum foil not safeguarded by the completely dry film is
engraved away to create a circuit.
Removing: Remove the subjected completely dry film on the safety circuit. The
developing, etching, and stripping devices is a horizontal DES line.
Pre-treatment of covering film: the result and approach are the same as
those of pre-treatment of dry movie.
Paste the cover film: line up the cover movie with the noting line. After
that, paste the cover movie on the board and use high warmth to pre-fix the cover film. The cover movie
plays a shielding and safety function on the circuit. The devices consists of an automated cover film
laminating device, iron, etc.
Pushing and curing: With heat and high-pressure pushing and high-temperature baking,
the glue in between the covering film and the board is treated to attain the purpose of close bonding in
between both. The main tools consists of a pressing device and oven.
Surface area therapy: Flexible printed circuit surface treatment mainly consists of
immersion gold or gold plating. According to client needs, metals such as nickel and gold are
transferred on the exposed pads of FPC making use of chemical or electroplating principles. It protects
the pads and maintains their solderability.
Electric screening: Inspect whether there are open short circuits or four-wire problems
with mechanical tools. The main gadget is an electric testing maker and a flying probe tester.
Assembly: According to the placement markings or hole placements, the reinforcement or
electro-magnetic movie is connected to the product.
Silk screen printing: Printing text ink onto products through the screen printing
principle, mainly printing product models, production cycles, various component logos, etc. The primary
equipment includes a silk screen printer, oven, text inkjet printer, etc.
Molding: The end product form of the consumer is developed through mechanical or laser cutting.
Final check: Check the appearance and surface condition of the product through manual
visual inspection and equipment to separate good products from defective products.
Perform reliability testing on the item to verify whether it meets client demands. The devices consists
of CCD, AVI, dependability screening devices, etc.
From the above intro of each manufacturing process, we can be seen that FPC manufacturing calls for
different modern technologies.
The manufacturing procedure is troublesome and hard. As a result, compared to average PCB, the
production price of flexible circuit card is higher. And it takes more time.
Nevertheless, FPC’s excellent flexibility, lightness, and integrity, FPC provides a lot more
possibilities for devices and items in many fields. And it is significantly favored by engineers.
Rigid-PCB vs Flexible PCB
1) Base Material
They make use of various substrates. Rigid printed ciruit board use glass fiber and epoxy resin, while
flexible circuit card utilize polyester movie or polyimide.
2) Plasticity and Bendability
Flexible printed ciruit board have good bendability, can be folded up and curved at will, and have solid
plasticity. Rigid circuit card can not be curved and are used to set up and maintain electronic
components.
3) Suitable Circumstances
flexible printed circuit board is mainly used in flexible circuits, such as flexible display screens,
vehicle panels, and various other items that require to be folded, bent, and decreased dimension. PCB is
suitable for general circuit card of numerous requirements, such as control circuit boards, audio
printed ciruit board, signal printed ciruit board, and so on.
4) Features
Advantages of flex-PCB: light-weight, tiny size, can be used in a smaller space; high reliability, can
withstand larger flexing and folding.
The downsides are high expense and facility production process; strong plasticity, very easy build-up of
fixed fee, and vulnerable to short circuits and failings.
The benefits of PCB: PCB assembly is easy and steady. Manufacturing costs are reduced. A high level of
automation can enhance production effectiveness.
The negative aspects are plus size, hefty weight, not resistant to dropping, and restricted area
framework.
In recap, various kinds of circuit boards have their advantages and downsides. So, we think about which
circuit board to select based upon our product requirements, cost, efficiency, and environmental
management. After that, the PCB maker will certainly create it.
Application of Versatile Printed Ciruit Board
Flexible printed printed ciruit board is widespread in lots of fields due to its exceptional
characteristics. The certain applications are as follows:
1) Consumer Electronics
In consumer electronics, versatile printed ciruit board are extensively utilized, such as smartphones,
laptops, and so on. Taking smartphones as an example, they can accomplish extremely integrated design,
making the phone thinner, a lot more attractive, and much more reputable.
2) Clinical Area
Flexible circuit card are used for interior links of wearable tools, medical tools, and various other
products to boost the comfort and portability of the tools.
3) Car
In the vehicle area, versatile circuit card can deal with intricate circuit formats and resonance
settings, improving the safety and security and reliability of vehicles.
4) Aerospace
In aerospace, versatile circuit boards have come to be an essential selection for inner circuit
connections in airplane due to their light-weight and high reliability.
What to Consider When Selecting a Flex-PCB Manufacturer?
Some questions you require to ask prior to picking a flex circuit producer:
• What are the specs of your flexible circuit card, and can the maker satisfy them?
• Is the Flex-PCB producer a specialist proofing, small batch, or mass cpu?
• Does the flexible printed circuit quality fulfill your requirements?
• Does your FPC spending plan cost match the manufacturer’s quote?
• Exactly how promptly can FPC suppliers deliver products?
Orinew Technology has actually been working in the PCB market for 12 years. We supply you with one-stop PCB
assembly solutions. You can trust Orinew Technology with whatever from element purchase to PCB assembly. We have a
specialist technical group and multiple PCB factories and PCB distributors. If you need any type of PCB
services, you can call us.
