Electronic components in various consumer and non-consumer devices are connected using rigid boards. A rigid printed circuit board, or PCB, is a type of circuit board constructed on a non-flexible base layer.
There is a massive distinction between rigid PCB and flexible PCB. Different from the other, the former is adaptable. For this reason, they have different use cases. Additionally, Rigid-Flex PCB is available.
What is a Rigid PCB?
As a subset of PCBs, rigid boards account for most of PCB production. Consisting of a solid substrate substance, it effectively stops the circuit board from warping. The computer motherboard is a typical example of a stiff PCB.
The motherboard is a multi-layer printed circuit board (PCB) that transfers data and power supply between the computer’s central processing unit (CPU), graphics processing unit (GPU), and random access memory (RAM).
Whenever the PCB itself must be shaped and kept that way for the duration of the equipment’s operation, a rigid PCB is the best choice. Rigid printed circuit boards (PCBs) can range from a single layer to as many as ten.
Characteristics of Rigid PCB
- Characteristic#1: Unlike Flex PCB, which is impossible to bend and shape in any way thanks to its FR4 reinforcement, rigid PCB is a type of conventional PCB that is inherently stiffer.
- Characteristic#2: Connecting the various parts of a rigid PCB is possible by using copper trances and routes laid out on the board. The board’s strength and rigidity come from its foundation material, a hard substrate.
- Characteristic#3: A computer’s motherboard is the best example of a stiff PCB with a rigid substrate.
- Characteristic#4: Rigid printed circuit boards (PCBs) are immovable after production.
- Characteristic#5: To put it simply, rigid PCB is more cost-effective than its flexible counterpart. They’re plain traditional rigid PCB, yet you’ll find them in all electronics.
- Characteristic#6: Both flexible and stiff printed circuit boards (PCBs) have their own benefits and drawbacks. Both are commonplace on circuit boards and serve the purpose of interconnecting numerous electrical components.
Manufacturing of Rigid PCB Circuit Boards
A rigid PCB comprises multiple layers of material that are adhered to and cured by heat and pressure to form a solid board. It is possible to create a sturdy printed circuit board by utilizing the following layers.
Layer#1: Substrate Layer
The substrate layer comprises fiberglass, sometimes called the base material. FR4 is the most popular fiberglass used to give boards their rigidity and stiffness. It comes in handy as a rigid substrate material.
Other materials like phenolics and epoxies also come in use, but they can’t compare to FR4 in terms of quality. On the other hand, they are more affordable and have their distinctive foul odor.
When manufacturers place solder on a phenolic layer for an extended period, the layer delaminates because the decomposition temperature is too low.
Layer#2: Copper Layer
Manufacturers bond copper foil onto the board’s top substrate layer with heat and glue. Ordinarily, you will see that both sides of a circuit board are copper laminated before manufacturers put it into service.
However, some inexpensive gadgets only have one copper layer. The weight of various boards is measured in ounces per square foot to indicate their relative board thickness.
Layer#3: Solder Mask Layer
The solder mask sits atop the copper material plating. Because the copper layer lacks insulation, there is a chance that conduction material may damage if they come in contact.
Layer#4: Silkscreen Layer
Above the solder mask lies the silkscreen layer. Putting some character or sign on the board makes it much easier to read and interpret. Silkscreening is most common in white. Gray, red, black, and yellow are some of the other options.
The Difference between Rigid PCB and Flex Circuits
Most people picture a rigid printed circuit board (PCB), abbreviated to PCB. These boards have conductive rails and other elements laid on a non-conductive substrate to connect multiple electronic components.
It is common for manufacturers to use glass in the non-conductive substrate of rigid circuit boards because it gives the board strength and rigidity. Rigid circuit boards offer excellent component support and thermal resistance.
A flexible printed circuit board (PCB) is a type of circuit board that employs a polyimide or other flexible base material instead of a rigid one and nevertheless has conductive traces on a non-conductive substrate.
Because of their bendable substrate, flexible PCBs can tolerate mechanical stress, release heat, and conform to various configurations. Flex PCBs are desirable for usage in compact and cutting-edge electronics due to their inherent flexibility. Notable distinctions between printed circuit boards (PCBs) and flex PCBs include:
- Conductive Material: Due to the need for bending in flex PCBs, manufacturers may opt for rolled annealed copper as a conductive material rather than electro-deposited copper.
- Manufacturing Process: Overlay or coverlay is a method used by producers of flexible PCBs to protect the boards’ exposed circuitry instead of a solder mask.
- Cost: Flex PCBs are often more expensive than rigid circuit boards. However, engineers realize indirect cost reductions when they use flex PCBs to reduce the size of their devices.
What are the Benefits of Rigid PCBs?
Benefit#1: Small Size
Compared to flexible PCBs, rigid PCBs typically offer smaller dimensions, which is an advantage in many applications. The PCB’s small footprint allows for a wide range of complicated circuitry to design around it.
It’s more convenient for compact application infrastructure. Along with the need for smaller electrical devices comes the need for tiny components that companies need to connect correctly. The PCB serves as the foundation for such an endeavor.
Benefit#2: Low Electronic Noise
Manufacturers developed the printed circuit board to cut down on electronic hum and buzz. The electronic components on the circuit board come in use to reduce electrical currents between them.
It results in the release of minimal radiation. Rigid PCBs are less likely to pick up electromagnetic waves when electric and radiation currents are low. Doing so can reduce the amount of noise generated by moving parts.
Benefit#3: Movement Immunity
To attach all the parts on a PCB to the board, manufacturers use Solder flux. Companies use this procedure in a certain way to ensure that the components remain in place even when the PCB is in severe operating conditions. This benefit makes rigid PCBs an excellent material for electronics subject to vibration and movement.
Benefit#4: Ease in Repair and Diagnostics
Because of how the manufacturers construct PCBs, servicing and fixing them is simple. The PCB’s components are all well-labeled, making assembly and disassembly straightforward. An exposed and well-organized PCB signal channel is a significant advantage. By doing so, the maintenance worker can track them simply throughout their cycles.
When to Use Rigid PCBs and Flex Circuits
- There is a price difference between flex circuits and rigid PCBs, with the latter being the more common option. As for my use of the word “typically,” it’s because there are some applications where the use of flexible PCBs might be cheaper than the use of rigid PCBs when factoring in the total cost of ownership. Recognizing that flexible PCB may prevent the need for components like connectors, wire harnesses, and other circuit boards is a prerequisite to accurately estimating the total cost of ownership. Reducing the need for these parts in a design helps save money on raw materials, assembly labor, and waste.
- We can find Rigid PCBs in many standard and cheap electronics such as laptops and desktops, audio keyboards, SSDs, flat-screen TVs and monitors, children’s toys, medical devices, and other electronic gadgets.
Nonetheless, GPS units, tablets, smartphones, cameras, and wearables may use flexible PCB because of their small size and high-performance requirements.
- Flex PCBs come in handy not only in high-tech applications because of their increased complexity; in fact, even low-tech applications like LED lights can benefit from flex PCB technology due to their simplified installation.
How to Choose between a Flex PCB and a Rigid PCB?
Manufacturers use both rigid and flex PCBs in various products. However, some uses are better than others. Consider your application’s needs, your industry’s preferences, and the potential financial impact of employing rigid PCBs or flexible printed circuit boards before making a final decision.
Finding the proper source is just as important as using high-quality circuit boards. For printed circuit board manufacturing and assembly, go no further than Hillmancurtis, a global leader in producing multi-layer boards and double sided PCBs. Customers may expect high-quality PCB manufacturing services and prototype PCB Assembly services at competitive rates and in an atmosphere where they feel safe and respected.
Finding the best rigid PCB manufacturing is one of the most challenging tasks. However, make sure to get all the information about Rigid PCBs before you think about buying one.
The main thing you need to focus on before purchasing a Rigid PCBs circuit board is finding trustworthy and reliable manufacturing. I hope this article on Rigid PCBs was of help to you. For more informative articles, stay tuned!