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Rigid Flex PCB Manufacturer 20L Rigid With 8L Flexible

Offering a variety of cost effective solutions and capabilities to manufacture single or double flex with multilayer rigid PCB, we will help you exceed all your applications requirements.

Rigid Flex PCB Manufacturing Service

Rayming Rigid flex PCB board manufacturing solutions are custom designed for many top electronic industry. Fabricated with dependable high stardard quality control and  reliability, our Rigid flex Board are built to withstand the rigors of aerospace, Robot control, medical, and military applications. As a reliability replacement for wire and wire harness assemblies,rigid flex circuit provide a significant cost saving with no reduction in performance.Our pcb engineer team can assist you from early rigid-flex design stages of your application all the way to final production for all your flex and rigid-flex circuit needs.

Rigid flex PCB capabilities: 

Rigid Board: Up to 20 layer ( accept buried or blind hole design)  

Flex Board: 8 Layer ( Accept PI,Aluminum, Fr4 stiffener, and other special materials requirement )

Need engineer support and want to estimate cost,pls send PCB file to sales@raypcb.com now 

Rigid flex PCB have been used in the military and aerospace industries for more than 20 years. In most rigid flex pcb boards, the circuitry consists of multiple flexible circuit inner layers selectively attached together using an epoxy pre-preg bonding film, similar to a multilayer flexible circuit. However, a multilayer rigid flex PCB incorporates a board externally, internally or both as needed to accomplish the design.

Rigid flex PCB combine the best of both rigid boards and flexible circuits integrated together into one circuit. The two-in-one circuit is interconnected through plated thru holes. Rigid flex circuits provide higher component density and better quality control. Designs are rigid where extra support is needed and flexible around corners and areas requiring extra space.

rigid flex pcb manufacturers

Flex and Rigid-Flex PCB applications also provide increased reliability. Mean time between failure rates (MTBF) typically exceed those of standard PCB sets with discrete wires and connectors, often becoming the choice of companies and engineers alike for its dependable and consistent performance.

Rigid-Flexible Circuit Board Manufacturing  & Assembly at RayMing Technology .Flexible Printed Circuit Boards are one of the most popular types of circuit boards used in a variety of industrial and commercial applications. At RayMing, we manufacture flexible printed circuits keeping the needs of our customers in mind. Our circuit boards provide quality and durable performance while being cost-effective in terms of manufacturing.

Our Standard Offerings We specialize in single and double-sided circuits, as well as multi-layer rigid and flex PCB assembly. The flex circuits are built to the exacting specifications of our customers.

  1. Flexible Printed Circuit Boards with 8 layers rigid PCB
  2. Single-Sided Flexible with rigid PCB board up to 6 layer
  3. Double-Sided Flexible Printed Circuit Boards  with 4 layer to 12 layer rigid pcb
  4. Multilayer Flexible Printed Circuit Boards with multilayer rigid PCB

Application of Rigid-Flex PCB

1.Industrial application

Industrial application includes rigid-flex PCB used in industry, military, and medical. Most industrial parts require the characteristics of accuracy, safety, and resistance to soil damage. Therefore, the characteristics required for rigid-flex PCB are high reliability, high precision, low impedance loss, complete signal transmission quality, and durability. However, due to the high complexity of the manufacturing process, the output is small and the unit price is relatively high.

2.Mobile phones

The application of rigid-flex PCB in mobile phones, such as folding mobile phone hinges, camera modules, keypads, and radio frequency modules, are common.

rigid-flex_pcb

3.Consumer electronic products

Among consumer products, DSC and DV are representative of the development of rigid-flex PCB, which can be discussed in terms of performance and structure. Rigid and flexible boards can connect different PCB rigid boards and components three-dimensionally. Under the same circuit density, the PCB total usable area and the circuit carrying capacity can be increased. The signal transmission limit of the contacts can be reduced, and reduced Assembly error rate. On the other hand, because the rigid-flex board is lighter and thinner, the wiring can be bent easier, so reducing the volume and weight will be helpful.

4.Automotive

Rigid-flex PCB is commonly used in the automotive industry. Here is a list of examples: the buttons on the steering wheel which connects to the motherboard, the connection of the car video system screen and the control panel, the operative connection of the audio or function keys on the side door, and the reversing radar imaging system, sensors (including air quality, temperature, and humidity, special gas regulation, etc.), vehicle communication systems, satellite navigation, rear-seat control panels, and front-end controller connection boards, vehicle detection systems, etc.

Rigid-flex PCB reduces the assembly size and weight of electronic products, avoiding wiring errors and increasing assembly flexibility. It also improves reliability and realizes three-dimensional assembly under different assembly conditions.Flexible Printed Circuits (FPC) flexible structure, small size, light weight, and flexibility can meet the needs of 3D assembly. Interconnection technology has been widely used and valued in the electronic communication industry. In recent years, the trend towards rigid-flex boards further shrinks the entire system, the volume, and enhance its function.

Advantages of Rigid-Flex PCB:

  • Space-saving: Save space without connectors
  • Flexible design: Flexible with 3D design
  • Enhancing product reliability (without connector)
  • Simple assembling process
Rigid-Flex PCB Design Guide By AutoTRAX

Disadvantages of Rigid-Flex PCB:

 

Comparison and analysis of different materials vs. Rigid-flex PCB

Design OptionsFPC Boards Build Up FPCThin Laminate circuit boardRigid-flex Circuit boardsMini Cable Wire HarnessCoaxial Cable
MaterialPolyimideThin LaminateFr4 Laninate and PolyimideCable/wire and connectorsCable and Connectors
ApplicationsDynamicStaticDynamicDynamicDynamic
Examples     

Key Message:

  • Rigid-Flex PCB can eliminate some connectors in the 3D assembly

Common structures of Rigid-flex PCB

rigid flex board
  1. The rigid flex board is to glue one or more rigid layers on the flexible board. The circuit on the rigid and flexible layersare connected through metallization. Each rigid-flex board has one or more rigid areas and a flexible zone
The circuit on the rigid and flexible layers
  1. The combination of one flexible board and several rigid boards, and the combination of several flexible boards and several rigid boards,

The electrical interconnection is realized by drilling, plating holes, and laminating processes. According to the design requirements, the design concept is more suitable for installing and debugging the device and the welding operation. The installation of the assembly is more flexible.

one flexible board and several rigid boards

Design Suggestions of Rigid-flex PCB

Rigid flex PCB board is a product segmentation that promotes technical level and application field of flexible circuit boards to help system products move to a broader space. Not only can the product be more miniaturized, but it also can solve many problems in assembly and wiring.

Structural considerations are the most critical factor in the design of Rigid-flex. It is necessary to make the process simple, highly reliable, and achieve low cost and application.

1.The thickness should be reduced as much as possible, and the types of materials must also be reduced.

Rigid Flex PCB that is too thick adversely affects the miniaturization of assembled thick products. It also causes inconvenience to the manufacturing process, especially pressing. In addition, the types of materials used by Rigid-Flex include copper foil, polyimide film, and acrylic glue. Different materials, such as different materials, will cause considerable challenges in dimensional accuracy. Simultaneously, due to the large difference in thermal expansion coefficient, the adhesion between the layers after thermal shock also needs attention.

2.Stress prevention at bending points

In addition to the process of hot pressing, it is necessary to reduce the stress on the contact edge of the flex and rigid board or provide additional reinforcement. The best policy is to avoid bending points.

  1. Consideration of folding resistance and shock resistance. Wiring deployment must meet folding resistance. Prior consideration is needed if the product is being used in a high-vibration environment.
  2. Process considerations Pre-imagine the problems that may occur in the process, simplify the process to reduce costs and increase yield

Design Tips for Rigid-Flex PCB

rigid flex circuit

There are many differences between the flex and rigid board in CAD design of rigid-flex PCB

1) Design requirements for flexible zone circuit:

1.1 Avoid sudden expansion or contraction of the line and adopt a tear shape between the thick and thin lines.

Design requirements for flex pcb hole

Use rounded edges to avoid sharp corners:

Use rounded edges to avoid sharp corners:

1.2 When the pad meets the electrical requirements, the maximum value should be taken. A smooth transition line is used to connect the pad and the conductor to avoid right angles. The independent pad should be added with a toe to strengthen the supporting effect.

connect the pad and the conductor to avoid right angles

2) Dimensional stability: Add copper design as much as possible.

Add copper design as much as possible

Design as many solid copper ponds as possible in the waste area.

3) Design of cover film window

  1. a) Add manual alignment holes to improve alignment accuracy.
  2. b) The window design considers the range of glue flow;usually, the window opening is larger than the original design,

The specific size is provided by the ME design standard.

  1. c) Small and dense windows can use a special mold design: rotating punch, jump punch, etc.

4) Design of rigid-flex PCB transition zone

  1. For the smooth transition of the line, the direction of the line should be perpendicular to the direction of bending.
  2. The wires should be evenly distributed throughout the bending area.
  3. The wire width should be maximized in the entire bending area.

Try not to use PTH design in the transition zone,

Design of Coverlay and No flow PP in the rigid-flexible pcb transition zone

Design of Coverlay

5) Design of flexible zone with air-gap requirements

  1. a) There must be no through holes in the part to be bent.
  2. b) Additional protection copper wires are added to the two sides of the line. If the space is insufficient, choose the inner R corner of the bent part.

Additional protection of copper wire.

  1. c) The connecting part of the line needs to be designed as an arc.
  2. d) It is better to have a larger bending area, which lessens the effectin

6) Other

The flex board’s tool holes cannot be shared, such as punch hole, ET, SMT positioning hole, etc.

Manufacturing Capability of Rigid-Flex PCB

Manufacturing Capability of Rigid-Flex PCB
ItemStandardLimit
1Min.Line/space3/3mil2/2mil
2Min.PTH/LAND150/450mm100/300um
3Min.Blind Via/Land100/300um80/250um
4Min.BGA Pitch500um400um
5Min.PTH Aspect ratio3:15:1
6Min.Via Aspect ratio0.75:11:1
7AvailablePlus IPlus II
rigid-flex pcb rigid side desig
PartSYM

ITEM

Standard (um)Limit (um)
On the rigid sideaCu(P/G0 to boarder600400
bPad edge to border800500
cParts edge to border800500
dS/M opening to border200100
eNon-PTH to border800500
fLegend to border500400
gAdhesive squeeze out1500800
On flex SidehDistance of rigid edge60004000
rigid-flex PCB flex side pcb design
ItemStandardLimit
1Min:outline tolerance±125um±100um
2PTH Diameter tolerance±75um±50um
3NPTH Diameter tolerance±50um±50um
4CVL opening to conductor (a)±200um±150um
5Center to center tolerance (b)±100um±50um
6SMD edge to outline tolerance±100um±75um

Material Characteristics of a Rigid-Flex Board

Typical Rigid-Flex PCB Material Feature

Material Description Specification Flexible Laminate Polyimide (adhesive-less or adhesive) Rigid Laminate FR-4 or glass-polyimide C-stage laminateCoverlay and Bond PlyAdhesive coated polyimide film Prepreg No-flow FR-4 or polyimide prepreg Build-up Material Resin costed copper foil or build up dielectrics

Rigid-flex material selection

Rigid PCBFlex PCB
Base substrate

Phenolic/Paper

Epoxy/Glass

Polyimide/Glass

Metal Core

Polyimide

Polyester

Adhesive layer

Expoxy

Phonolic

Polyimide

Acrylic

Epoxy

Conductor

ED Copper

High ductility

Copper

RA copper

High Ductility

Copper

ED copper

Introduction to Flexible PCB Materials

Introduction to Flexible PCB Materials

Base Raw Material

1). FCCL ( Flexible Copper Clad laminate)

  • Polyimide: KaptonÔ (12.5 mm/20 mm/25mm/50mm/75mm)
  • High flex life, good thermal management, high moisture absorption, and good tear-resistant
  • Polyester (25mm/50mm/75mm)
  • Most cost-effective, good flex life, low thermal resistivity, low moisture absorption, and tear-resistant

2).For FPC Material Status 2L FCCL

FPC Material Status 2L FCCL
Suppliers MaterialCharacteristicsCurrent Status
Taiflex2lpsHigh FlexibilityHVM
Rogers2 seriesHigh FlexibilityHVM
Nippon steelMCLow DimensionHVM
DupontACHigh FlexibilityHVM

3).For FPC Material Status 3L FCCL

FPC Material Status 3L FCCL 
Supplier MaterialCharacteristicsCurrent Status
TaiflexI X NHigh FlexibilityHVM
Rogers7 seriesLow DimensionHVM
MicrocosmPSBRLow DimensionHVM
ArisawaLASWHigh FlexibilityHVM

1.Dielectric Substrates dielectric film: polyimide (PI), polyester (PET)

Characteristics of PI:

  1. Good heat resistance: The long-term use temperature is 260℃.In the short term, it can withstand high temperatures above 400℃.
  2. Good electrical and mechanical properties.
  3. Good weather resistance and chemical resistance.
  4. Good flame retardancy.
  5. The water absorption rate is high, and the size changes after moisture absorption. (Defect)

IQC must regard the dimensional change rate as an important acceptance index for PI incoming materials. The environmental control requirements of the production process are also stricter than rigid boards.

Polyester film PET has good mechanical and electrical properties such as tensile strength, water resistance, and dimensional stability after moisture absorption. However, it has a large shrinkage rate when heated and has poor heat resistance. It is not suitable for high-temperature soldering (Now the lead-free soldering temperature is 235+/-10 ℃), and its melting point is 250 ℃. Less used

Polyimide (PI) is the most widely used, and 80%  is made by DuPont in the United States.

2.Cover Layer

Function: Protect circuit, insulation, electrical demand, and board deflection.

Features: 1. Good electrical characteristics, 2. Good processability, 3. Excellent flexibility

Cover Layer from ½ mil to 5 mils (12.7 to 127µm)

Polyimide: (12.5 mm/15 mm/25mm/50mm/75mm/125mm)

High flex life and high thermal resistivity.

Cover Layer

1) Other protective films and covering film materials

2) Flexible solder mask

The most cost-effective, lower flex life, and better for registration.

3) PIC—Photo Imaging covercoat

Lower flex life, better for registration.

3.Adhesive Sheet

Bond-ply insulation combination layer with bonding effect.

Cover layer Glue overflow

Cover layer Glue overflow

Pressing conditions: 190℃/85(kg/cm2) gauge pressure/forming pressure 60sec

4.Conductive Layer

Rolled Annealed Copper (9mm/12mm/17.5mm/35mm/70mm)

  • High flex life, good forming characteristics.
  • Electrodeposited Copper (17.5mm/35mm/70mm)
  • More cost-
  • Silver In
  • Most cost-effective, poor electrical characteristics. Most often used as shielding or to make connections between copper layers.

5.SF-PC5000 Electromagnetic Wave Protective Film Thickness Characteristics

1) Ultra-thin – Total thickness is only 22 microns.

The hot-melt process is used for compound processing between the two insulating films.

The inner insulating layer is extremely flexible, and the outer insulating layer has excellent wear resistance.

2) The sliding performance and flexural performance greatly improved.

Since it has a better sliding performance than silver paste, it further promotes the thinning of the slide-type mobile phone.

3) Adapt to moisture-resistant reflow soldering.

Due to the improved insulating resin, the thinning is realized, and the gas penetration ability is greatly improved.

It is fully suitable for lead-free reflow soldering.

4) Good dimensional stability.

Compared with previous materials, the thermal shrinkage rate of the insulating resin in this product is less than one-tenth of the original.

As a single-sided shielding material for thin FPC and COF, it can significantly reduce the warping problem caused by material shrinkage.

6 .Additional Material & Stiffeners

The hard material is additionally pressed on the local area of the soft board for welding parts or adding reinforcement for installation.

Stiffeners types: FR4, Aluminum, PI

7. No / Low Flow PP

TYPE (usually very thin PP) is used for lamination of rigid and flexible boards.

  • 106(2mil)
  • 1080(3.0mil / 3.5mil)
  • 2116(5.6mil) w/o micro-via

Flow PP Manufacturers:       TUC, Panasonic, Arlon, Hitachi, Doosan

No / Low Flow PP

How are rigid flex PCBs made?

rigid flex pcb design

1.Drilling

When drilling a single-sided soft board, pay attention, and ensure the glue side is up to prevent nail heads. If the nail head faces the glue surface, the bonding force will be reduced.

2 Desmear

Generally, there are four methods for removing drilling pollution: sulfuric acid method, plasma method, chromic acid method, and potassium permanganate method.

PI produced less drilling stains in the rigid-flex board, while modified FR4 and acrylic acid produced more drilling stains.

Modified epoxy drilling dirt can be removed with concent rated sulfuric acid, while acrylic acid can only be removed with chromic acid. Polyimide is inert to concentrated sulfuric acid and is not resistant to strong alkalis (potassium permanganate). PI will swell in strong alkalis. The same chemical treatment method cannot remove the drilling dirt of the rigid-flex PCB.

Plasma uses a radiofrequency energy generator to make ions, electrons, free radicals, free radicals, etc., lose their electrical properties under vacuum, and show neutrality. At this time, the drilling of various resin types can quickly and evenly pass from the hole. The wall is removed, and a certain bite is formed to improve the reliability of the metalized hole.

When using Plasma to remove the hard and soft board hole drilling dirt, the biting speed of various materials is different, from large to small:

Acrylic, epoxy, polyimide, glass fiber, and copper,

From a high-power microscope, it is evident that there are prominent glass fiber heads and copper rings. In order to remove the fiber heads and copper rings, it is usually adjusted with a very low concentration of alkali after degreasing of PTH (usually KOH), of course. Rinse with high-pressure water. (PI is not resistant to strong alkalis)

3.Chemical copper deposition:

PTH of flex board commonly used black hole process or shadow process (Shadow)

The electroless copper of the rigid flex PCB is the same as the principle of the chemical copper of the rigid board.

The flexible material polyimide is not resistant to strong alkalis. As a result, the pretreatment of copper sinking should use acidic solutions. Acid colloidal palladium should be used for activation rather than alkaline ion palladium.

At present, most chemical copper deposits are alkaline, so the reaction time and the concentration of the solution must be strictly controlled. If the reaction time is long, the polyimide will swell. The insufficient reaction time will cause cavities in the holes and poor mechanical properties of the copper layer. Although the board can pass the electrical test, it often fails to pass the thermal shock or the user’s assembly process.

4.Copper plating:

To maintain the flexibility of the flex board, sometimes choose the plated copper, called Button Plate. (The pattern transfer of the plated hole is done before the selective plating)

The electroplating principle is the same as the hard board.

5.Graphics transfer:

Same process as the rigid board.

6.Etching and film removal:

Etching: The etching solution mainly includes acidic copper chloride and alkaline copper chloride etching solution. Since there is polyimide on the flexible board, acid etching is mostly used.

Film removal: same process as rigid PCB

Pay special attention to the infiltration of liquid at the rigid-flex joint, causing the rigid-flex pcb joint board to be scrapped.

7.Laminating:

Laminating is to press copper foil, P sheet, inner flexible circuit, and outer rigid circuit into a multilayer board.

The lamination of the rigid-flex board is different from the lamination of the soft board or rigid board. It is necessary to consider the problem of easy deformation of the flexible board during the lamination process. Also, the smooth surface after the rigid board is laminated is of concern as well. For the issue of sex, we must also consider the protection of the flexible window at the junction of the two rigid areas.

Lamination control points:

1)The amount of glue flowing in No-Flow PP prevents excessive glue from

2) Because No-Flow PP has an opening, there will be a loss of pressure during lamination, so use a conformal sheet and release film when laminating.

No Flow’s PP needs to open a window at the rigid-flex joint (using a gong or punching method). After the outer green oil is completed, the rigid part of the rigid-flex joint is uncovered and laminated during the appearance processing.

3) Before lamination, the rigid outer layer and flexible inner layer must be baked to eliminate latent thermal stress and ensure the quality and dimensional stability of the hole metallization.

4) Appropriate cushioning materials should be selected. The ideal cushioning material should have good conformability, low fluidity, and non-shrinking characteristics during cold and hot processes to ensure that the lamination is free of bubbles and flexible materials during the lamination process. This is to make sure no deformation can occur.

Quality inspection after lamination: Check the appearance of the board to see if there are quality problems such as delamination, oxidation, and glue overflow. Also, the peel strength test should be carried out to ensure quality.

8.Surface Finish

After the protective film (or solder mask) of the flexible board is laminated, the bare copper surface to be soldered must be made of organic soldering preservatives (Organic Solderability Preservatives; OSP), hot air leveling (HASL), nickel gold or Electric nickel gold)

Quality control points on the surface of the rigid-flex board

  1. Thickness,
  2.  Hardness,
  3. Porosity,
  4. Adhesion

Appearance: exposed copper, copper surface pinhole/dent/scratch/yin and yang color.

9.Profile processing:

Most of the profile of high volume flexible board is mold-cutting.small volume is laser. The process is as follows:

Mold design → mold making → test beer → (first board) measurement of size → production.

When CNC the rigid-flex board, special attention should be paid to the uneven shape and rough edges caused by the easy distortion of the flexible part.

In order to ensure the accuracy of the outline processing size, the process method of adding the gasket and the thickness of the rigid plate is adopted and should be fixed or compressed when CNC.

In addition, low feed and high speed will cause the edges of the board to be burnt. Meanwhile, the high feed and low speed will break the knife and the edge of the board.

Rigid-flex board and flexible board are glued to open windows, cover film open windows, base materials open windows, and reinforced processing with CNC and punching methods can also be used.

Manufacturing Flow for different Rigid-Flex PCB Project

Case 1: Motorola 1+2F+1 Mobile Display & Side Keys

1+HDI design, BGA Pitch: 0.5mm RIGID FLEX PCB

PCB features: 1+HDI pcb design, BGA Pitch: 0.5mm

Flex board thickness: 25um with IVH hole design, PCB thickness: 0.295 +/- 0.052 mm

Inner LW/SP: 3/3mil

Surface treatment: ENIG

Process flow of Rigid-Flex PCB 1

 
Process flow of Rigid-Flex PCB 1

Case 2: Motorola 1+2F+1

Motorola 1+2F+1 rigid flex pcb

PCB features: 1+HDI design

BGA Pitch: 0.5mm

Flex board thickness: 25um without IVH hole design, the whole

PCB thickness: 0.275+/-0.028mm

Inner LW/SP: 3/3mil

Surface treatment: ENIG + Silver Paste

Process flow of Rigid-Flex PCB 2

Process flow of Rigid-Flex PCB 2

Summary of Rigid-Flex PCB

8 layer rigid flex pcb
  1. The PCB design trend is the development of light and thin. In addition to high-density circuit design, there are also three-dimensional connection and assembly methods of rigid flex PCB.
  2. The design structure of the flexible board and rigid flex board is complicated, and the production process is difficult.
  3. The Cover-lay, No-Flow PP,and finished boards of the rigid-flex board need to be stamped with a mold. The mold size design and the size expansion control of the material are very critical.
  4. The material variety of the rigid-flex board is expensive.
  5. It is difficult to control the alignment accuracy of the rigid-flex board, and it requires high dimensional stability of the material.
  6. The manufacturing process of the rigid-flex PCB has strictrequirements for the operation workers.

The electronics industry keeps advancing and so is PCB production. Rigid flex PCB circuit boards have been used in several applications for over 20 years. Most consumer products like cell phones, cars, batteries, and laptops make use of these PCBs.

Rigid flex PCB are commonly utilized in the manufacturing of most electronics today. In this article, we will talk about rigid flex PCB, their features, benefits, and a lot more.

What is Rigid Flex PCB?

A rigid flex PCB combines a hardboard and a flexible circuit. The manufacturing process involves the use of traditional rigid boards; however, some layers are flexible circuits that run through the hardboards. The board fabricator attaches PTH to connect layers of rigid boards to areas of the flexible circuit.

These pcbs comprise both flexible and rigid circuit substrates. In most cases, rigid flex PCB boards feature flexible substrates of many layers. These substrates are fixed to rigid circuit boards.

The substrates are attached externally or internally. The attachment of these substrates depends on the application of the board. A rigid flex PCB can resist many flex cycles without any failure. The components of a rigid flex board are constantly flexible.

Rigid flex circuit boards offer a greater component density and improved quality control. Rigid designs are useful where support is required and flexible designs come in handy in applications that extra space is necessary.

Rigid Flex PCB Types

Rigid flex boards come in various types which include;

Single side Rigid Flex PCB

These boards come with a layer of conductive material. Its side gives space for the integration of different electronic components. Single side boards feature a layer of flexible and rigid substrates.

Double side Rigid Flex PCB

This type of semi flex pcb is made of a layer of flexible substrate and rigid substrate. Flex substrate helps to enhance flexibility while rigid layer boosts compactness. Double-sided rigid flex PCB ensure greater routing traces due to the via within the two layers.

Multiple-layer Rigid Flex PCB

Multilayer rigid flex pcbs feature three or more conductive layers. The substrates in these boards serve as insulators.

Rigid Flex PCBs Advantages

Rigid flex boards provide a solution for limited space conditions. This type of board ensures the secure connection of components in devices while assuring contact stability and polarity. Rigid flex PCBs have several advantages which includes

Space saving: A rigid flex board is used in applications where space is important. For instance, rigid flex materials are utilized for thermal scanners. This device needs less space to fit in connectors and wire harnesses. Using rigid flex boards enables you to build circuitry that fits your device.

Flexibility: Rigid flex board offer flexibility which makes it easy to produce a board for an existing device instead of producing a device with board’s specifications.

Reliability: These boards are more durable and reliable. Fewer interconnects helps to reduce potential failure, hence, improving reliability. The low mass of these boards also minimizes the effect of vibration and shock.

Low cost: Utilizing rigid flex PCBs helps to reduce the cost of production. Rigid flex boards required a fewmaterials for their assembly. Rigid flex boards are much cheaper than rigid boards. These boards are a complete circuit as there is no need for wire harness installation in the enclosure you mount it on.

Resistance to harsh temperature: Rigid flex circuit boards can withstand varying temperatures. These PCBs can withstand exposures to UV rays and radiation. They also resist harsh oils and chemicals.

Ease of testing: These boards are very easy to test since all the sub-circuits are interconnected. The ability to get rid of connectivity issues before assembling the components prevents unnecessary expenses and wastage.

Great thermal stability: Polyimide is utilized during rigid flex circuit board assembly process. Polyimide is known to have great thermal stability. This makes these boards ideal for defense and military applications.

Rigid Flex Boards Limitations

Although rigid flex boards have several benefits, they also have their own limitations.

Requires intensive labour: Rigid flex boards manufacturing is labor intensive due to the PCB sensitivity and variations in flex and rigid substrates.

Elaborate production: Since two separate substrates are involved in the production of rigid flex board the production is time-consuming and elaborate.

Complex production process: The fabrication of rigid flex boards is complex, unlike other PCBs. It requires the utilization of suitable and effective software which makes production cost expensive.

Rigid Flex Boards Material

Rigid flex pcb comprise several materials which are discussed below;

Substrate and Coverlay Films

Woven fiberglass is one of the commonest materials used in the production of rigid flex boards. Epoxy resin impregnates this woven fiberglass. This makes the fiberglass resistant to sudden shock and constant vibrations. Therefore, these materials are utilized:

  • Polyimide:Polyimide has a great thermal resistance and as such can withstand constant movements and vibrations. This type of material that can resist heat. It is a great option for applications that are subjected to fluctuating temperatures. Polyimide is very tough and flexible.
  • Polyester: Polyester is a common material for rigid flex boards. Polyester is known for its flexibility. This material resists moisture and chemicals. It is useful in applications exposed to harsh environments. When you use the appropriate substrate, the lifespan and strength of the substrate are guaranteed.

Coatings

  • Cover lays:Cover lays are created by combining adhesives with flexible films. Cover lays are very important in rigid flex PCB assembly. They provide inclusive shielding for the assembly.
  • Cover coats:Cover coats are coatings applied on a circuitry’s surface. Polyurethane is utilized in this case.

Adhesives

Adhesives play a significant role in the production of rigid flex circuit boards. Adhesives enable secured connections to be formed between the substrate and the materials for conductor. There are different types of adhesives used in the production of rigid flex boards.

  • Polyester adhesives:Polyester adhesives are mostly used in the rigid flex boards’ fabrication. These adhesives have low bond strength and are less likely to withstand unpredictable and high temperatures. However, these adhesives are now modified to resist heat.
  • Polyimide adhesives: These adhesives have the ability to resist different temperatures. It can withstand about 500°C. This capability makes it an ideal option for use in sensitive applications. It is used in applications such as military and defense.
  • Epoxies:Epoxies are a kind of adhesive used for the production of the rigid flex board. They can resist corrosion and varying temperatures. Epoxies are flexible and have bond stability. To enhance flexibility, small amounts of polyester are included in epoxies.
  • Acrylic adhesives:Such types of adhesives offer thermal stability. They can withstand chemicals and corrosion. They are much cheaper and easy to use.

Conductor Materials

Copper is the most preferred and commonest material for assembly of this PCB. This is because copper is a good conductor of electricity. The two major types of copper used are rolled copper foil and electrodeposited copper foil.

These foils vary in thickness and weight. Surface treatment of the board is required before the assembly process. Chemical treatment is also important. This helps to enhance bond strength and increase adhesiveness. Chemical treatment on the foil also prevents oxidation and reduces the likelihood of bond degradation.

Insulators

Polyimide film is the most preferred insulator. This film is utilized on the flex circuits’ base. Polyimide is utilized in the internal parts of the multiple layer circuits.

Applications of Rigid Flex PCBs

Rigid flex circuit boards are commonly used in many applications due to their features and benefits. They are utilized in the following applications

Military equipment: Most of the military equipment is designed with rigid flex boards. This is due to the reliability of these boards and their ability to withstand varying temperatures. A rigid flex board is used in communication devices, tracking and surveillance systems, and weapon guidance systems.

Aerospace equipment: Rigid flex PCB manufacturers design these PCBs to withstand harsh temperatures. Therefore, a rigid flex board is made use of in the production of radar communication systems and radar equipment.

Automotive devices: In the automotive industry, rigid flex PCB help in the manufacturing small devices like comfort control units and control modules. Rigid flex boards are used for transmission control, music systems, and navigation systems.

Consumer appliances: Rigid flex PCBs play a significant role in the production of most consumer appliances. Consumer appliances such as washing systems, remote controllers, electronic irons, and lighting systems are made with these PCBs.

Telecommunication systems: The telecommunication industry also utilizes rigid flex boards. These boards are used in applications such as handheld devices, wireless communication devices, routers, base stations, and communication satellites.

Conclusion

In today’s electronic industry, rigid flex PCBs play a vital role. These PCBs combines rigid and flexible substrates, making them an ideal option for most applications today. Rigid flex PCB manufacturers design this PCB with effectiveness and reliability in mind. These PCBs are specifically designed for use in high-performance and high-speed applications. With these types of PCBs, a lot is achieved.