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How to build complex gadgets with 4 Layers HDI Rigid-flex PCB?


An Ultimate Guide to HDI PCB

Nowadays HDI has become one of the fastest-growing technologies in PCBs. Rigid-flex boards have made undeniable progress in the world of modern electronics. So, 4 Layers HDI Rigid-flex PCBs are ideal for all the latest and smart electronic devices.

Moreover, HDI rigid-flex boards are highly versatile and you can tailor your needs with these boards across a wide range of industries. PCB boards are extremely suitable for aerospace, military, medical devices and also useful to implement towards several commercial products.

We have prepared this guide for you so that you can easily understand the advanced features of HDI Rigid-flex PCBs. As well as, why high-density applications are not possible without HDI Rigid-flex PCB boards?

4 Layers HDI Rigid-flex PCB

What is rigid-flex PCB?

The rigid-flex PCB boards are hybrid circuit designs that integrate elements from both flexible and hardboard circuits. These are flexible at some points as well as rigid at others.

Moreover, PCB designers internally bury the flexible layers that completely penetrate into the rigid sections of the PCB. These two-in-one circuits have interconnected via plated thru-holes.

In fact, rigid-flex circuits can provide extremely better-quality control and higher component density. They are also a perfect choice to use in high-shock and high-vibration environments.

What is HDI technology?

HDI stands for High-Density Interconnect. Moreover, this technology has got extreme popularity in the field of modern electronic industry. HDI Boards consist of blind or buried vias.

This is ideal to use in 4 Layers HDI Rigid-flex PCBs. They often contain micro vias of. 006 or may have a lesser diameter. Basically, these boards have a higher circuitry density in comparison to traditional PCB boards.

What is HDI PCB?

Actually, circuit boards that contain a higher wiring density per unit area than the conventional boards are called HDI PCBs. Moreover, they have;

  • finer lines and spaces
  • minor vias and capture pads
  • and higher connection pad density.

What is a 4 Layer PCB?

the stack up in 4-layer PCB boards is completely elaborate. These boards contain two inner layers, designers have placed them in the following pattern.

Such as they have sandwiched the inner layer 1 and 2 between the bottom and top layers.

What are 4 Layers HDI Rigid-flex PCB?

4 Layers HDI Rigid-flex PCB boards are a special combination of rigid and flex circuits with four conductive copper layers. Generally, four-layer boards have two rigid layers and two flexible layers.

PCB designers have ideally designed these boards as they are rigid where you need extra support. In addition, they are flexible around corners and in those areas where you require extra spaces.

So, due to these additional features, you can fold or continuously flex these rigid-flex circuits to maintain the shape of areas that need extra support.

By using HDI technology in 4 layers of rigid-flex PCB boards, electronic designers can easily place much more components on both sides of the raw PCB.

As consumer demands are changing with each passing day, so technology must also have the ability to change.

How HDI technology can decrease the overall size of components?

With the help of HDI technology, you are capable to use multiple via processes, such as blind via technology and via in pad.

Moreover, these technologies also allow the electronic designers to place components that are closer together. As well as greatly smaller to each other. Using 4 Layers HDI Rigid-flex PCB boards can decrease the overall size of pitch and components.

Further, as it decreases the size, it allows for more I/O in smaller geometries. Hence, it is beneficial to faster transmission of signals along with the significant reduction in the signal loss and in crossing delays.

What is the material description of 4 Layers HDI Rigid-flex PCBs?

The HDI technology with rigid-flex circuits is extremely reliable as well as well-proven. The flex part of this PCB is very good at fixing problems with special freedom relating to weight and space.

Basically, PCB manufacturers etch flexible circuits or flexible wires on the polymer base material on a polymer film circuit or printed copper.

Moreover, for light and thin electronic devices that have complex and compact construction. The design solutions of 4 Layers HDI Rigid-flex PCB contain a single path for three-dimensional assembly of a multi-layered complex.

Total flexible assembly volume and weight of 4 Layers HDI Rigid-flex PCB

In fact, the total flexible assembly volume and weight are 70% lower in comparison to traditional wire rope. The flexible parts can increase their strength with the help of a liner or reinforcement material for extra mechanical stability.

These PCB boards can reduce the hardware required for Nellian, like,

  • common solder joints
  • body
  • cables
  • and wiring in conventional electronic packages.

Moreover, allowing flexible panels in these boards actually provide higher assembly reliability.

How 4 Layers HDI Rigid-flex PCB are ideal for high-vibration environments?

Actually, these HDI boards are ideal to use in high-vibration and high-shock environments. The 4 Layers HDI Rigid-flex PCB boards are extremely shock-resistant.

Further, they also have the great ability to survive in high-stress environments. So, they are ideal to use in comparison to several other PCB solutions.

Why high-density applications impossible without 4 Layers HDI Rigid-flex PCBs?

Nowadays there are various applications that have less space to integrate complex functions. And there are many assemblies that have less surface area for all the essential cables and connectors.

So, HDI Rigid-flex PCB boards can easily economize space to solve this issue. It will be right to say that PCB manufacturers have designed these boards for the high-density device population.

Additionally, by using these circuits electronic designers can design lighter conductors and denser device populations into their products. Moreover, 4 Layers HDI Rigid-flex PCBs also can provide freeing space for additional product features.

What are the 5 advanced features of HDI Rigid-flex PCB?

HDI Rigid-flex PCBs with 4 layers are ideal to use when assemblies get crowded with more than four connected boards. Additionally, these circuit boards provide the following most advanced features such as:

  • They can survive hundreds of thousands of flex cycles.
  • These boards also can survive high levels of shock and vibration.
  • Can highly increase the density of the circuit.
  • Also, can reduce the overall package weight.
  • As well as can decrease all necessary assembly operations.

Are 4 Layers HDI Rigid-flex PCB costly?

Basically, 4 Layers HDI Rigid-flex PCB boards may be more costly in comparison to standard boards. They are also expensive to produce and design. But they offer extreme benefits than standard boards.

For example, they highly reduce the size of the board, so are ideal to fit into smaller spaces. Moreover, these good characteristics help to decrease the overall system costs.

Rigid-flex circuits also can prove to be much more reliable as they need fewer interconnects, related parts, and components. So, they require less maintenance in the long run.

All in all, according to several electronic engineers these boards are not costly when they deeply observe their features (several believe they are expensive).

4 Layers HDI Rigid-flex PCB 2021


The 4 Layers HDI Rigid-flex PCB boards are an undeniable need for a compact package. Moreover, they can highly reduce the overall weight of electronic devices. Hence, it is only because of rigid-flex boards that the latest electronic gadgets are smart and light in weight.

Although, the utilization rate of raw materials and production of rigid-flex PCB boards have caused them to raise costs. But if you cooperate with PCB manufacturers in the early stages of the project, they can complete the design work at a lower cost.

So, you can easily avoid all excessive costs as well.

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