Hello, friends, I hope all of you are enjoying your life. In today’s tutorial, we will have a look at Rigid Flex PCB. The PCB is an acronym of a printed circuit board, this board is used almost in each and every electronic circuitry and device like computers, GPS (Global Positioning System), mobile phones, etc. On this many conductive tracks are designed by the copper layer for assembly of different circuits. There are numerous types of PCB according to construction and uses like single sided PCB, double-sided PCB, rigid PCB, aluminum PCB, flex PCB, etc. In today’s post, we will explain its types called rigid-flex PCB (printed circuit board).
This category of printed circuit board is a combination of both rigid and flexible printed circuit boards. This board has features of rigidity and flexibility that exist in flexible and rigid circuit boards separately. In today’s post will have a look at its working, construction, advantages, practical uses, and some other related parameters. So let’s get started with Rigid-Flex PCB.
Rigid Flex PCB
- Rigid-Flex PCB is being manufactured by the combination of rigid and flexible printed circuit boards. This circuit board usually comprises of many layers of flexible substrate substance and one or more than one board of rigid PCB.
- The designing of this board is a little bit difficult compared to a rigid circuit board because this module is designed according to a three-dimensional environment that also provides high spatial efficiency.
- The main benefit of this board is that it provides highly flexible, decreases flex thickness and less expensive circuit board.
- As on the traditional printed circuit board we can assemble a large no of components on any side of a rigid circuit board. Since the incorporation that exits among rigid and flex circuitry, a rigid-flex assembly does not use connectors among the units. In its place, the flex circuitry electrically joins the scheme together.
- The absence of connectors provides some benefits that are mentioned here.
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- It increases the capability of circuitry to send a signal with less distortion.
- Houses precise impedance value.
- It reduces joining issues like cold connections.
- It also decreases the weight of the board.
- Each rigid-flex printed circuit board is divided into different parts that have different categories of layers and quantity.
- The number of layers can be larger than the flexible portion and construction substance can be FR4 (Flame Retardant) or polyimide.
Features of Rigid-Flex PCB
- These are some features of a rigid-flex printed circuit board that are mentioned here in detailed.
Feature | Parameters |
Quality Grade | It follows the IPC 2 protocol. |
quantity of Layers | This board can have two to twenty-four no of layers. |
Quantity for orders | One piece to one thousand plus pieces you can orders. |
creation Time | It takes two to five days for creation. |
Material | DuPont (PI25UM), FR4 (flame resistant) |
Board Dimensions | Its minimum dimensions are six milimeter x six millimeter and maximum are 457 milimeters x 610 millimeters. |
Board Thickness | The thickness of this board is 0.6 millimeters to five millimeters. |
Copper Weight | Copper weight is from 0.5 ounces to 2.0 ounces. |
Minimum Tracing | Three mil. |
Solder Mask Sides | According to file. |
Solder Mask Color | Its color can be green blue, white yellow, black. |
Silkscreen Sides | According to the file. |
Silkscreen Color | Its color can be white, black, and yellow. |
Surface Finish | HASL(Hot air solder leveling) Lead – free HASL – RoHS (Restriction of Hazardous Substances) ENIG – RoHS |
Min Annular Ring | Four-mil. |
Min Drilling Hole Diameter | Eight-mil. |
Impedance control | ±10 percent. |
Advantages of Rigid Flex PCB
- These are some benefits of this circuit board.
- This circuitry board permits you to purchase and construct a board according to your device’s requirements.
- This PCB is not heavy and has less size.
- This module can be very easily adapted to any working environment due to this feature it can easily twist and use other circuitry.
- The absence of a soldering connection from this board increases its reliability for different projects.
- It provides less damage to circuitries.
- This PCB board also bears higher temperatures as in its construction polyamide is used that helps to bear temperature. Due to temperature bear capability, it used in different medical devices.
- For the production of this board we not need to purchase large no of material so this makes it cost-effective.
- This board also can affect ultraviolet radiation and also resist oils and severe chemicals.
- The structure of this board is such that we can make circuits on any side of the board.
Applications of Rigid-Flex PCB
- These are some applications of this PCB board.
- This circuit board is used for numerous engineering projects for simple designing to complicated structures like the aviation system, military instruments, and mobile phones.
- Due to not heavyweight it used in medical devices like pacemakers.
Points to Consider to Buy Rigid-Flex PCB
- Before buying this circuit board you must consider some points that are described here.
- This PCB provides many specifications due to this it best option for many industrial applications.
- So it is significant that before selection this board follows the requirements of your circuitry.
- For less weight and place this PCB is the best option for your projects.
- If you are a regular project maker always try to buy groups of circuit boards that will be cost-effective.
Challenges in Designing Rigid-Flex
Complex Design
- Rigid boards follow a complicated design process as compared to rigid boards. There is a need to work for mechanical and electrical parameters for rigid and flexible parts of the board such as material selection, layer stack up, etc
Bend Radius
- The calculation of the proper bend radius for the flexible part of the board is important. The selection of a bend radius having a small value can cause damage and affect signal quality.
Material Selection:
- The use of accurate rights for rigid and flex parts of the board is important. Different materials come with different thermal expansion coefficients, that cause issues in handling different temperature conditions.
Signal integrity and EMI:
- The signal quality and EMI control needed for the flexible part is important since can cause issues. The flexible features of the substrate and signal proximity for the bend part have affected signal quality.
Connector Connection:
- The accurate position of connectors for rigid and flexible parts of the board is important for proper design. If not accurately connectors placed causes mechanical stress and problems with board reliability
Layer Transition:
- Accurately transitioning the signal from rigid to flexible board layers is a challenging process. If not accurately aligned, layers cause signal degradation.
Thermal Management:
- The proper heat dissipation for rigid-flex boards is difficult for conventional rigid boards. Substrate flexibility can restrict the application of the heat-sinking process.
Assembly :
- The assembly process of these boards is more complex than others. So follow some more instructions for board assembly and make sure that components can connect correctly and be soldered easily.
Testing and Inspection:
- Inspection and testing are also difficult since they have a complex structure. Certain types of tools are used for the testing board.
Mechanical Reliability:
- A flexible part of the board needed to handle repeated bending and flexing without damage is required, and it is best when the board is used for foldable devices.
Cost:
- These boards are high-cost to manufacture since they use complex designs and machines. Materials are also high-cost.
Design for Manufacturability (DFM):
- Getting good manufacturability for the board is difficult. Engineers must follow the features and limitations needed for the manufacturing process and work with manufacturers to get the required results.
What are the disadvantages of rigid-flex PCB?
- Rigid-flex board is high cost as compared to the conventional rigid board since it has a complicated design, materials, and difficult manufacturing process.
Related Posts
- Aluminum PCB (Printed Circuit Board)
- Multilayer PCB (Printed Circuit Board)
- Rigid PCB (Printed Circuit Board)
- Flex PCB (Printed Circuit Board)
- High Frequency PCB (Printed Circuit Board)
- Single Sided PCB (Printed Circuit Board)
- Rigid-Flex PCB (Printed Circuit Board)
- Double sided PCB (Printed Circuit Board)
This the complete post on the Rigid Flex PCB if you have any queries about it ask in comments. see you in the next tutorial. Have a good day.
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