HDI rigid-flex PCB is a type of rigid-flex printed circuit board that incorporates blind and buried vias. Therefore, it not only retains all the advantages of a conventional rigid-flex PCB, but also possesses the distinctive features of an HDI (High-Density Interconnect) board, including:
Feature
Integration of rigid and flexible PCB advantages
HDI rigid-flex PCBs combine the strengths of rigid printed circuit boards (PCBs) and flexible printed circuits (FPCs) through specialized manufacturing processes. They maintain the high mechanical strength, structural stability, and multilayer routing capability of rigid PCBs, while also providing the flexibility to bend or fold in designated areas.
Lightweight and compact design
Rigid-flex circuit boards are lightweight and compact, making them ideal for electronic products that require thin, light, and space-saving designs. This provides a significant advantage in portable devices and applications with limited installation space.
High signal transmission efficiency
With shorter signal transmission paths, finer line widths, and smaller via diameters (blind and buried vias), HDI rigid-flex PCBs offer higher signal transmission efficiency. This reduces signal attenuation and electromagnetic interference, making them suitable for applications with high signal integrity requirements.
Adaptability to complex spatial layouts
The flexible sections allow HDI rigid-flex PCBs to conform to complex three-dimensional structures. This enables 3D wiring and efficient use of space, meeting the demands of intricate and compact electronic designs.
Excellent temperature resistance and flame retardancy
HDI rigid-flex circuit boards exhibit strong resistance to high and low temperatures and possess excellent flame-retardant properties. These characteristics ensure reliable performance in harsh environments and high-reliability applications.
Foldable without affecting signal performance
The combination of rigid and flexible structures allows the circuit board to be folded or bent without compromising signal transmission, making it especially suitable for devices that require repeated folding, movement, or mechanical deformation.
The structure of a rigid-flex circuit board typically consists of the following parts
Double-layer FPC substrate
This forms the core flexible section of the rigid-flex PCB and is typically designed with gold fingers for reliable electrical connection with other electronic components.
01
Gold fingers
Located at one end of the FPC substrate, the gold fingers provide stable electrical connectivity and high wear resistance, ensuring dependable insertion and signal transmission.
02
Two-layer rigid PCB substrate
Positioned at the opposite end of the FPC substrate, the two-layer rigid PCB acts as the circuit board's input and output interface, supporting component mounting and signal distribution.
03
FR4 reinforcement layers
FR4 material is applied between the double-sided gold fingers at the FPC end and between the two FPC layers at the rigid PCB connection area. This reinforcement enhances mechanical strength, rigidity, and overall structural stability.
04
FPC layer structure design
The section of the double-layer FPC substrate sandwiched between two FR4 layers features a hollow structure. This design ensures sufficient thickness and rigidity at the gold finger end, while maintaining excellent flexibility in the middle section where the FPC connects to the rigid board.
05
Application
Rigid-flex PCB is mainly applied in following area:
Consumer electronics
In devices such as smartphones and tablet computers, rigid-flex PCBs enable three-dimensional interconnection between multiple rigid boards and components. This increases circuit integration density, improves signal transmission reliability at interconnection points, and reduces assembly errors.
Industrial control and high-reliability systems
Rigid-flex boards are widely used in applications requiring high reliability, high precision, and low impedance loss, including industrial automation equipment, military systems, and medical devices.
Automotive electronics
In automotive applications, rigid-flex PCBs are commonly used for steering wheel controls, infotainment display systems, control panels, reversing radar and imaging systems, sensors, and in-vehicle communication systems, supporting compact layouts and reliable performance.
Aerospace and aviation
Due to their high mechanical strength, stability, and ability to adapt to complex spatial layouts, rigid-flex PCBs are extensively used in aerospace and aviation applications where flexible wiring and lightweight designs are critical.
Medical electronics
In medical PCB design, HDI rigid-flex PCBs are increasingly adopted for their high wiring density, compact size, and excellent signal integrity, making them suitable for advanced diagnostic, monitoring, and therapeutic equipment.
Lead time
Normally, a 4-layer HDI rigid-flex PCB prototype requires more than 25 days for fabrication.
With quick-turn rigid-flex PCB services, the lead time can be significantly reduced; however, it still typically requires around 10 days to complete.
Customized product
Most of our products are customized based on the original Gerber files provided by our customers.
After receiving the original Gerber files, we convert them into working Gerber files for production use.
During this conversion process, we adjust certain parameters-such as hole diameter, trace width, and trace spacing-to optimize manufacturability and ensure smooth production.
Package and warranty
All our products are vacuum-packaged with desiccant to ensure optimal protection during storage and transportation.
The shelf life of vacuum-packaged circuit boards varies depending on the surface treatment process, typically ranging from 3 to 12 months. The details are as follows:
Shelf Life for Different Surface Treatment Processes
ENIG (Electroless Nickel Immersion Gold)
Can be stored for up to 12 months under vacuum packaging with desiccant protection.
Lead-Free HASL (Hot Air Solder Leveling)
When no special storage adjustments are made, the shelf life is typically about 3 months.
OSP (Organic Solderability Preservative)
Has a shelf life of 3–6 months under vacuum packaging with desiccant protection. However, if stored improperly (e.g., without desiccant or with insufficient vacuum sealing), the shelf life may shorten to around 3 months.
Immersion Gold (Chemical Gold Plating)
Shelf life can reach 6–12 months, provided that sealed packaging and desiccant are used.
Company advantage
1. We guarantee a response within 24 hours to all customer inquiries and complaints.
2. Our factory offers 1-day sample production for 2-layer boards and provides rapid manufacturing services for small and medium orders, ensuring short lead times and on-time delivery.
3. We support multiple payment options, including EUR, USD, RUB, and CNY, through PayPal, T/T, and other convenient methods.
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