Rigid printed circuit boards (PCBs) have been used in various basic devices which are not very complex. This is one of these old or initial types of boards before manufacturers started using flexible or rigid-flex boards. Even now, these PCBs find applications in several electronic and electromechanical products, wherein motherboards and calculators are peculiar devices with rigid boards. Rigid PCBs use traces, also called connective pathways that are etched on a non-conductive substrate. Is that all? Obviously not. Would you like to know more about these PCBs? If yes, then read this post till the end.
A Quick Introduction to Rigid PCBs
Rigid circuit boards are the most common and oldest types of PCBs. They are constructed using a solid substrate, preventing them from bending or twisting. In this type of circuit board, the number of layers is not a constraint. This means a rigid circuit board can be single-layered or multiple-layered. However, it cannot offer the bending ability and compact sizing required in today’s miniature electronic devices. One of the most common materials used for manufacturing rigid PCBs is fiberglass or precisely FR4 as it offers several benefits and also keeps the component intact at the position certain epoxies may also be used to make these PCBs; however, nowadays they are rarely used. Aside from the peculiar basic devices, these PCBs are used for experimentation and elementary projects as they are cost-effective.
How Are Rigid PCBs Made?
Rigid PCBs are made by joining different layers together using heat and adhesive, giving proper shape to the board material. These circuit boards are developed with the following layers.
- Substrate Layer: The substrate layer is most popularly referred to as base material. Like any other type of PCB, the substrate layer of rigid circuit boards is made from fiberglass. Flexible PCBs are an exception to this. This material provides rigidity and thickness to the circuit boards, while in the case of cheap rigid boards, epoxies may be used, and they are not preferred as they lend a peculiar smell to the board.
- Copper Layer: The copper coating is done on the top of the substrate layer. It is a thin layer of copper foil laminated on the circuit board using the appropriate amount of heat and adhesive. In the case of double-sided PCBs, both sides of the board are laminated with copper. However, some PCBs may have copper only on one side. The copper thickness can vary based on the application requirement and is represented by weight unit that is in ounces per square foot. Most circuit boards have 1 ounce of copper per square foot; however, some may use 2 or 3 ounces of copper.
- Solder Mask Layer: This is placed on the top of the copper layer and usually gives a green color to the board. It is mainly used to insulate the copper layer to avoid any damage with elements that could disrupt the copper traces. This is one of the important layers in the rigid PCB assembly as it helps to solder board components at the appropriate places.
- Silkscreen: On the top of the solder mask is called the silkscreen layer. The silkscreen adds numbers, symbols, and letters to the circuit board for easy identification and tracking of components and wires. White is the most common color used for silkscreen. However, any ink color can be used, such as grey, black, red, yellow, and so on.
What Are the Applications of Rigid PCBs?
Rigid PCBs offer immense benefit to certain devices as they can be made small in size with minimal components, and are low on maintenance. Rigid circuit boards are mainly used in industries where components need to deal with stress, vibration, and elevated temperatures. Given below are some applications of rigid PCBs.
- Electronic Computer Units (ECUs)
- Transmission Sensors
- Power Distribution Junction Boxes
- AC/DC Power Converters
- Auxiliary Power Units (APUs)
- Airplane Cockpit Instrumentation
- Control Tower Instrumentation Systems
- Temperature Sensors
- Electromyography (EMG) and Magnetic Resonance Imaging (MRI) Systems
- Gas and Pressure Controllers
- Robotics
Do you think rigid PCBs would meet the requirement of your application? If you are not sure or have any questions on this, consulting a trusted and experienced PCB manufacturer and assembler is a wise option. With vast years of market presence and experienced teams, Accelerated Assemblies would not only assist you in making the right decision but also offer customized rigid PCB assembly to fulfill your application need. In addition to the rigid PCB assembly, the company offers fabrication services for varieties of PCBs from flexible to metal core PCBs, and more.
