Your Reliable Rigid PCB Manufacturer in China

The characteristics of rigid PCB are as follows:

• It does not fold or twist like a flexible PCB. Rigid PCB comes with FR4  reinforcement, and therefore it comes with extra stiffness.
• It comes with high density. The high density helps to integrate integrated circuits for the advancement of mounting technology.
• It is made of copper trances and paths that help connect various board components. The base material of rigid PCB is built with rigid substances to provide extra rigidity.
• It provides high reliability. A well-designed and tested Rigid board can be operated for many years.

Rigid PCB Properties

• Much modern equipment and devices use rigid PCB in various devices. For example computers, mobile phones.
• Flexible PCB is expansive, and a rigid printed circuit board is cheaper. Most electronics devices use rigid circuit boards, which is a big reason for the reduced price of electronic devices.

Various layers are joined together to make a rigid PCB. Manufacturers use adhesive and heat to merge those layers, which provide a rigid shape to the material.

The layers used in a rigid PCB are as follows:

1st: Substrate Layer

The substrate layer is made of fiberglass, and it is the base material of a rigid printed circuit board.

FR4 is common fiberglass and the most common substrate material to make a rigid printed circuit board. That provides rigidity to the PCB board.

Other types of substrate materials that are also used in rigid PCB are Phenilcs and epoxies.

But they are not as good as F4. They are cheap and deliver a bad smell.

Phenolics have a low decomposition temperature which delineates the layer after placing solder for a long time.

Rigid PCB Layers

2nd: Copper Layer

After placing the substrate layer manufacturer placed a laminated copper foil on the board. They use adhesive and heat to set the copper layer.

Typically manufacturers laminate both sides of the board with copper.

You can find Some rigid PCBs that come with only one copper layer on the board, but they are cheap and of low quality.

The thickness of the board varies, and the unit for this thickness is ounces per square foot.

3rd: Solder Mask Layer

After putting the copper layer comes the solder mask layer. This layer protects the copper layer from any kind of damage when a conduction material touches the copper layer.

4th: Silkscreen Layer

The silkscreen layer comes after the solder mask layer. This layer adds symbols or characters on the board to provide a better understanding.

Mainly white-colored silkscreen is used in this layer, but you can find other colors also such as red, gray, yellow, and black.

There are three major types of rigid printed circuit boards (RCBs):

Single-Sided PCB: This is the most basic rigid PCB that manufacturers offer to customers. Here the circuit board has only one layer of copper on one side.

This type of rigid printed circuit board has a simple design and quick manufacturability, therefore best for rapid production

Double-Sided PCB: This type of PCB comes with copper conductive layers on both sides, and so, they are called double-sided PCB. This type of PCB has become industry standard now.

You will find double-sided PCBs in various applications such as fine line surface mounting, coating, solder, and high copper builds.

Multi-layer PCB: As the name suggests, these PCBs come with numerous copper conductive layers separated by equal dielectric layers.

These PCBs can contain up to 14 to 16 conductive copper layers. These PCBs offer you the flexibility to the designers that no other PCB can.

Rigid PCBs can hold up to 40 layers. Want to know more about the manufacturing process of multi-layer PCB? Read our guide to the multilayer PCB manufacturing process.

To know more about the types of PCBs watch the below video

The coating that joins the bare board and the components of the rigid PCB is called the surface finish. This is applied for two reasons, ensuring solderability and guarding exposed copper circuits.

A wide range of materials is used in the surface finishing process of rigid PCB.

The surface mounts are becoming complex day by day, and new regulations are changing the industry standard. Therefore, you should pick the right surface finish for rigid PCB.

Manufacturers use different materials in the rigid PCB surface finishing process. We have listed some of the most popular surface finish materials below:

Electrolytic Gold: Electrolytic Gold is also called ‘hard gold.’ In this surface finishing process, manufacturers apply a gold layer over a nickel coat.

This is a highly durable finishing process. The process is applied in those areas where the risk factor is high.

Hard Gold

This type of surface finishing is highly expansive and demands extra processing and intensive labor.

Immersion Tin: ISn or immersion Tin is a metallic finish and applied on the copper circuit board. Manufacturers collect the ISn using a chemical displacement reaction.

The primary purpose of this finishing is to extend the lifespan of the copper board by shielding it from oxidation.

Moreover, the finishing creates a flat surface and is reworkable. But one disadvantage of this finishing is it can be damaged from handling.

Electroless Nickel Immersion Gold: Probably the most popular material for surface finishing. This metallic coating consists of two layers. Here 2-8 μin Gold (Au) is used over 120-240 μin Nickel (Ni).

The Nickel layer guards the copper, and the gold layer takes care of the Nickel layer. Soldered components are used over the Nickel layer.

ENIG coheres to RoHS regulations, and for this reason, this finishing is arguably the most popular in the industry.

You should know this is an expansive finishing process.

Hot Air Solder Levelling: It is also referred to as Lead-free HASL, and this is the most dominating surface finishing process most manufacturers use.

The circuit board is immersed in a molten pot of a lead/tin alloy in this process.

Then the air knives blow hot air across the board surface to remove the excess solder.

The HASL provides an unintentional benefit in the manufacturing process. Here the PCB is exposed up to 265°C temperature.

If there are any potential delamination issues, the temperature will identify that before attaching any expansive components to the board.

The finishing process is low cost and provides a long lifespan.

Moreover, you can rework any error that happens through the manufacturing process.

Wire Bondable Gold: Gold and electrolytic nickel consist of this surface finish. The Nickel provides a higher level of hardness for appropriate protection.

The Gold does not contain grain stiffeners as it is bonded to electrical wire. Thermal or Aluminum wedge welding can bond the surface finish to wires.

Like any other PCBS manufacturer, use a specific procedure for rigid PCB boards. Here is the sum-up of the entire manufacturing process:

• Material Preparation: The manufacturing process begins with a bare production board. Manufacturers clean the production board using various chemicals and send it for the application of photoresist film. Proper precautions are taken in the transportation process to protect the board from damage.
• Circuit Pattern Exposure: After finishing the photoresist application, manufacturers lay the board for numerous circuit artwork patterns. They use UV light for transforming circuit images over the production panels. The process is performed either on a single side or both sides of the board.
• Etching: After transforming the circuit pattern on the board, etching begins. In this process, manufacturers chemically etched the circuit patterns onto the board. Manufacturers use specialized automatic chemical etching machines and other special handling equipment to perform the operation.
• Drilling: After etching the circuit pattern onto the board, it’s time to drill holes for the circuit patterns. All the holes must adhere to the specifications and must be of a specific size. Manufacturers use special drilling machines or laser drills to accomplish the size. Laser drills can cut a clean hole quickly.
• Copper Plating: After completing the drilling process, it’s time for the copper plating process. In this process, manufacturers apply additional copper onto the circuit board for creating a layer-to-layer connection. Manufacturers use an automatic copper plating system for this operation.
• Mounting: Now it’s time to prepare the PCB. Typically manufacturers use Routing or CNC technology for rigid PCBs. Manufacturers pass the leads of the components through the drilled holes and solder to pads on the circuit board’s opposite side.
• Testing: Before declaring the rigid PCB fit for any application, it must go through several testing procedures: Automated Optical Inspection (AOI), Electrical,  and Functional. The electrical test ensures every electrical connection of the rigid PCB is working fine. AOI tests assembling and soldering Functionality test confirms that the rigid PCB is functional and ready for production.

Rigid PCB designers consider various performance features to pick and choose materials to manufacture rigid PCBs. Some of the popular choices are:

FR4 epoxy laminate: FR4 is the most commonly used material in rigid PCBs. They have excellent electrical, mechanical, and thermal properties. Besides, they provide ideal strength to weight proportion.

Teflon laminates: For high-speed circuitry applications, Teflon laminates provide superb electrical characteristics. Teflon laminates are pricier than polyamide laminates but deliver high-speed capabilities to the designers.

For both large and small-sized rigid PCB customers will get the following advantages:

Compact Size: Rigid PCBs are compact in design and therefore small. With the compact size, customers can create a wide range of complex circuitry for their desired applications. For its size, it occupies minimal space in a piece of application equipment. As electronic devices are becoming smaller day by day, rigid PCBs are playing a very crucial role there.

Rigid PCBs are compact

Low Electronic Noise: Rigid PCBs reduce the electronic noise in the application. The electronic components of the circuit board are assembled in a way that minimizes the in-between electrical current.

And the result is low radiation emissions. Intense radiation and electricity reduce the chance of picking electromagnetic waves by the PCB.  As a result, cross-talking between the components is very low.

Movement or Immunity: The manufacturers fix all the components to the board by using solder flux. The manufacturing process is very precise, and no components can move, even in a challenging environment.

That’s why devices that are often shaken and moved use rigid PCB.

Easy Repair and Diagnostics: Repairing and maintaining the rigid PCB is straightforward because of the design and manufacturing process.

Every PCB component is marked clearly, and therefore the assembling, and dissembling process is straightforward. Moreover, the signal paths are exposed very well and organized.

As a result, technicians can trace them easily while performing a repair or maintaining a task.

They are ideal for many applications for their features like easy maintenance and immunity to movement.

Those industries that require fixed components, face application stress and higher temperature use rigid PCBs. Here are some examples of applications:

Electronics and Automation Industry

Rigid PCBs can handle both light and heavy-duty applications. Many industries use multilayered PCBs as they can create buried connections and provide controlled impedance. Heavy-duty PCBs can tackle applications that generate high frequency and voltage.

Robotics uses Rigid PCB.

Here are some examples of automation applications that use rigid PCBs:

• Gas and pressure controls
• Robotics
• surge suppressors, etc.

Medical Industry

Medical applications prefer flexible PCBs, but in some cases, the medical industry also needs rigid PCBs. You will find Rigid PCBs in Non-Profitable and larger-sized medical equipment.

Here are some examples of equipment that use rigid PCB:

• EMG or Electromyography machines
• MRI or Magnetic Resonance Imaging machine,
• tomography equipment, etc.

Aerospace Industry

The aerospace industry has to deal with high-temperature and harsh environments. Therefore, you will find rigid PCBs quite a lot in the aerospace industry.

Rigid PCBs are built with aluminum and copper substrates and covered with elevated temperature laminates.

Rigid PCBs are used in Cockpit

You will find  some examples of equipment built with rigid PCBs Bello:

• Cockpit instruments,
• APUs or auxiliary power units,
• Power converters,
• Control Tower Instruments
• Temperature sensors, etc.

Automotive Industry

You will find rigid PCBs in nearly every vehicle. Like the aerospace industry, these PCBs are built with aluminum and copper substrates. Moreover, PCBs used in automobiles contain high-temperature laminates to protect them from engine overheating and harsh environmental conditions.

Here are some examples of rigid PCB applications in the automotive industry:

• ECUs or Electronic Computer Unit
• AC/DC power converter
• Junction boxes for power distribution
• Transmission sensors, etc.

The examples we provided are very among the wide range of applications that use rigid PCB.

As the name suggests, rigid PCBs are more rigid than flexible PCBs. But there are some other notable differences between rigid and flexible PCBs. They are:

• Manufacturing process: Manufacturers use an overlay or overlay process for protecting exposed circuitry of flexible PCBs. Rigid PCBs, on the other hand, use solder mask procedures to protect their circuitry.
• Conductive material: Flexible PCBs are meant to bend. To achieve that, property manufacturers use rolled annealed copper in flexible PCB. Rigid PCBs don’t need those flexible characteristics and use electro-deposited copper.
• Costing: Rigid printed circuit board for its compact nature reduces the weight and size of the design. Flexible PCB, on the other hand, gives the flexibility to shrink the device size. Typically flexible PCBs are more expensive than rigid PCBs.

To know more difference between Rigid and Flex PCB please watch the video

You can reduce your rigid PCB cost in various ways. Here are some examples:

• Choose your material wisely
• Minimize the circuit layer number
• Simplify the configuration
• Reduce material thickness
• Optimize and customize the design process

• Typically they are cheaper than flex circuits. However, flexible PCBs can reduce the total production cost for some applications and, therefore, practically become less expensive than rigid PCBs. Confused? Flex PCBs may not need components like wire harnesses, other circuit boards, or connectors. Eliminating these components from your design automatically reduces assembly and labor costs, material costs, and scrap costs.

Flexible PCB

• Many everyday electronic devices use rigid PCBs, such as a Desktop, Flat TV screen, Laptop, SSD, Flat monitor, Audio keyboard, Toys, and many other electronic gadgets. And, you will find flex PCBs in more sophisticated devices such as Tablet computers, cameras, smartphones,  wearables, etc.
• Some less sophisticated technologies also use flexible PCBs for their effortless installation process, such as LED lights.

Here is the list of IPC standards that are applied on both rigid and flexible PCBs. Please note that the ICP standard that we listed is not exhaustive. You can visit the IPC official website for the complete IPC standards list.

• IPC-2221A, PBC  Design Generic Standard.
• IPC-2223, Sectional Design Standard for Flexible PCB’s sectional design standard.
• IPC-4101, Base Material’s specification for Multilayer and Rigid PCBs.
• IPC-4202, Flexible PCBs’s Base Dielectrics
• IPC-4203, Cover sheets’ Adhesive Coated Dielectric for flexible PCBs and Adhesive bonding films.
• IPC-4204, Flexible Metal-Clad Dielectrics for Flexible PCB fabrication.
• IPC-6013, Performance and Qualification Specification for Flexible Printed Wiring

Quality inspection is mandatory for every rigid PCB. You should perform three quality inspection methods to be 100% sure about your rigid PCB. They are:

Visual Inspection: You can perform the visual quality inspection using a gauge, ruler, glass and vernier caliper, etc.

Rigid printed circuit board Quality Control

Electrical Inspection: You can also call it, connecting performance tests. You can use a multimeter and test the conductivity of conductive patterns of your rigid PCB.

General Technology Inspection: You can test the plates’ adhesion and solderability using this inspection method.

You can adopt other inspection methods for more detailed inspection, and it is better to take the help of a professional QC test company for that purpose.

The actual price depends on multiple factors. With the factors listed here you will be able to determine the cost of rigid PCB:

• Size of the PCB – Larger size will cost more.
• The number of layers – More layers required additional production time and increased the rigid PCB cost.
• Complexity – More complex technology will increase the price of rigid PCBs.
• Weight of the Copper foil– Thin copper will cost less, and thick copper will cost more.
• Trace/Space – Tighter space or trace requires more work and increases the price.
• The drill to copper– Smaller drill to copper will increase the price.
• Controlled impedance – If the design contains controlled impedance, the price will rise.

Rigid PCB is widely used in various industries. They use solid, rigid, and inflexible substrate material that prevents the board from bending.

We hope the article provided a better understanding of rigid PCBs. We provide the best rigid PCB in the market, and always welcome our clients with any sort of inquiry.

Feel free to send us a message for your search.