What is a rigid PCB?
A rigid PCB is a printed circuit board built on a solid, inflexible substrate, most often glass-reinforced epoxy laminate such as FR-4. It holds its shape in service and supports components mechanically. Rigid boards are the most common type of PCB and range from simple single-sided boards to complex multilayer designs.
Rigid PCBs explained
A rigid PCB consists of copper layers bonded to a stiff dielectric core. The core gives the board its strength, so it can carry heavy components, connectors and heat sinks, and be mounted with screws or card guides. It also stays flat during soldering, which makes automated assembly straightforward.
The most common base material is FR-4, a woven glass fabric impregnated with epoxy resin. Other rigid substrates include high-Tg and halogen-free FR-4 variants, PTFE and ceramic-filled laminates for high-frequency PCBs, and metal-core boards for thermal management, such as aluminium PCBs. Polyimide is used in rigid form for high-temperature applications.
Manufacturing a rigid board follows a well-established sequence. Inner layers are imaged and etched, then laminated together with prepreg under heat and pressure to form the stack-up. Holes are drilled and plated to connect the layers. Outer layers are imaged, plated and etched, followed by solder mask, surface finish and silkscreen. Boards are then electrically tested, routed out of the panel and inspected.
Rigid boards are described by layer count: single-sided, double-sided or multilayer. They can also include advanced features such as blind and buried vias, controlled impedance or HDI structures. Performance requirements for rigid boards are set out in IPC-6012, and visual acceptance in IPC-A-600.
When a rigid PCB is the right choice
A rigid PCB is the default choice when the board does not need to bend during assembly or in use. It suits most electronics: industrial controllers, power supplies, instruments, computers, consumer devices and the main boards of many larger products.
Rigid boards are usually the most economical option for a given circuit, because the materials and processes are mature and widely available. They are mechanically robust, easy to handle during assembly and simple to test.
Rigid is not the best choice when the product needs to fold into a tight enclosure, flex repeatedly, save weight, or replace cables and connectors between several boards. In those cases a flex or rigid-flex design may reduce assembly steps and failure points, even though the board itself costs more. The decision should look at the total cost of the product, including cables, connectors and assembly labour.
Rigid vs flex vs rigid-flex PCBs
Flex PCBs replace cables and fit tight spaces. Rigid-flex PCBs combine rigid areas for components with flexible interconnects, removing connectors between boards. Rigid boards remain the most economical choice when no bending is needed. Flex and rigid-flex add material and process cost, but can lower total product cost by removing cables, connectors and assembly steps.
Rigid PCBs in your quote request
In your quote request, state the base material and any Tg or halogen-free requirement, the layer count, the finished board thickness and copper weights, the surface finish and the IPC class. Include the Gerber or ODB++ data, a drill file and a fabrication drawing with tolerances. If you are unsure whether rigid, flex or rigid-flex suits your product, describe the mechanical constraints and we will raise the question with the manufacturer.
Need boards built? Upload your Gerber files for a free quote and DFM check from the right manufacturer in our network.
PCB manufacturing →FAQ about rigid PCBs
What is the difference between rigid and flex PCBs?
A rigid PCB is built on a stiff substrate such as FR-4 and keeps its shape, while a flex PCB is built on a thin polyimide film that can bend or fold. Rigid boards are cheaper and better at supporting heavy components. Flex boards fit tight or moving spaces and can replace cables. Rigid-flex boards combine both in one structure.
What are the main types of PCBs?
PCBs are usually grouped by structure and by layer count. By structure, the main types are rigid, flex and rigid-flex boards, plus metal-core boards for thermal management. By layer count, they are single-sided, double-sided and multilayer. Further categories include HDI boards with microvias and high-frequency boards made from low-loss laminates.
What material are rigid PCBs made of?
Most rigid PCBs are made of FR-4, a glass-reinforced epoxy laminate clad with copper foil. Variants include high-Tg and halogen-free FR-4. For RF and microwave circuits, PTFE-based and ceramic-filled laminates are used, and for high-power LEDs and power electronics, metal-core boards with an aluminium or copper base. Polyimide is used for high-temperature rigid boards.
Related terms
- FR-4
FR-4 is a flame-retardant laminate made of woven fibreglass cloth bonded with epoxy resin. It is the default base material for most rigid PCBs because it balances mechanical strength, electrical insulation, thermal performance and cost. Variants exist for high-Tg, halogen-free and high-speed applications, and the grade is chosen to suit the assembly process and operating conditions.
- Multilayer PCB
A multilayer PCB is a printed circuit board with three or more copper layers, separated by insulating dielectric and laminated together under heat and pressure. Inner layers carry signals or form solid power and ground planes, and plated vias connect the layers. Most multilayer boards use an even number of layers, such as four, six or eight.
- Double-sided PCB
A double-sided PCB, or 2-layer PCB, has copper conductors on both sides of a single insulating core, usually FR-4. Plated through-holes and vias connect the two sides electrically. It gives far more routing space than a single-sided board at modest cost, and components can be mounted on one or both sides.
- Stack-up
A PCB stack-up is the cross-sectional arrangement of copper layers, cores and prepreg that make up a multilayer board. It defines the layer order, dielectric thicknesses, copper weights and material properties. The stack-up is critical for controlled impedance, signal integrity, EMC performance and manufacturability, and it should be agreed with the manufacturer before layout is finalised.
- PCB thickness
PCB thickness is the overall thickness of a finished printed circuit board. The standard is 1.6 mm (about 0.062 inch), but boards from around 0.4 mm to 3.2 mm and more are common. Thickness is set by the stack-up of cores, prepreg and copper, and affects stiffness, connectors, impedance and cost.
- IPC-6012
IPC-6012 is the industry specification that sets the qualification and performance requirements for rigid printed boards. It defines what a finished bare board must meet — materials, plating, conductor and hole dimensions, electrical tests and reliability — for each of three performance classes. It is used together with the IPC-A-600 acceptability standard.