You must conduct a rigid-flex PCB cost comparison to know the circuit board you’ll use for your project.
Generally, flexible and rigid-flex PCBs are more expensive than similar-rated rigid PCBs.
Moreover, their manufacturing processes are labor intensive, increasing market prices.
However, it’s important to note that their mechanical and electrical benefits outweigh their shortcomings. By how much? Read on to find out.
Table of Contents
- What Are Rigid-Flex PCBs?
- Considerations When Comparing The Cost of Different PCBs
- Why Are Rigid-Flex and Flexible PCB Expensive?
- Factors Affecting Rigid-Flex PCB Cost
- FAQs
- Conclusion
What Are Rigid-Flex PCBs?
Rigid-flex PCBs are printed circuit boards that combine rigid and flex circuit board technologies.
In other words, some sections are flexible while others are rigid.
The flexible sections have substrate material that can twist, bend, and move in any direction in a three-dimensional space.
On the other hand, the rigid sections have rigid substrate materials.
Generally, the manufacturers use rigid parts for mounting the PCB onto a device.
Moreover, the flexible part bends around shapes for easier installation.
Considerations When Comparing The Cost of Different PCBs
(Rigid PCBs with surface mount components)
The manufacturing of a PCB comprises two steps, the first is producing the bare board, and the second is installing components.
In both stages, multiple considerations affect how much resources you’ll spend.
First, consider the fabrication factors like materials, board type, stack-up number, layers, ELIC, and HDI.
Materials like polyimide will always be more expensive than FR-4, raising the prices of flexible PCBs.
Additionally, ELIC and multiple lamination processes cost higher than rigid single lamination.
Therefore, boards that employ both technologies are costlier than most rigid boards.
Another consideration is the assembly process.
You will find that leaded processes are cheaper than through-hole and clean processes.
Moreover, consider the type of testing you’ll use to determine if your circuit board meets industry standards and regulations.
For instance, component inspection and value checks are cheaper than ionic contamination and flying probe tests.
Why Are Rigid-Flex and Flexible PCB Expensive?
(A flexible printed circuit board)
The materials that manufacturers use to manufacture flexible PCBs are costlier than those of rigid PCBs.
Moreover, flex and rigid-flex circuit boards need more engineering to produce than rigid PCBs.
For instance, the flex circuits require additional pressure-sensitive adhesives, stiffeners, coverlay, etc, that rigid PCBs don’t.
When it comes to rigid-flex PCBs, the flexible parts of the circuit board drive the prices high.
Additionally, the volume of production affects the cost of PCBs.
You can manufacture flex and rigid-flex PCBs for smaller volumes using mechanical routing or laser cutting.
The purpose of doing so is to facilitate the installation of surface mount components.
For higher volumes, mechanical routing is insufficient, and it’s better to go with steel rule dies.
However, as efficient as they are, steel rule dies are costlier to create.
Furthermore, you will disregard flying probe testing for hard-wired, labor-intensive tests.
Also, define the bend radius before manufacturing your flex and rigid-flex PCBs.
Failure to do so and your PCB may not bend or twist as you expect, leading to mechanical stress or even failure.
A contributing factor to the higher cost of these PCBs is the amount of work you will manually do.
Such includes the number of programs you must create so that the manufacturing process continues seamlessly.
Factors Affecting Rigid-Flex PCB Cost
(A woman going through purchase receipts)
The manufacturing process is a primary factor influencing rigid-flex PCB costs.
In other words, you must consider the variations in the fabrication processes of both circuit boards.
Generally, the flexible parts will cost more than the rigid sections. Here, let’s look at the factors that affect the cost of rigid-flex PCBs.
Material Choice
The material you’ll use to produce your printed circuit board determines its cost.
For example, you’ll spend more if you decide to go with FR-4 than with FR-2.
Additionally, using polyimide for the flexible section will raise the production cost.
However, be careful, as cheaper materials weaken the performance of your PCB.
As such, they lower your board’s mechanical properties, temperature reliability, and signal performance.
Size of Your PCB
The bigger the circuit board, the more materials to manufacture, and the costlier it gets.
But reducing a PCB’s size to save on costs may affect its performance and reliability.
Moreover, it may negatively impact its electrical and mechanical properties.
Hole Size
(A flex PCB with mounting holes)
The hole size affects the ease with which you will install components onto the printed circuit board.
For instance, you will find installing components into minute holes harder, while dealing with wider holes is easier.
Furthermore, the drilling method that you will adopt will influence the cost.
For example, laser drilling is more expensive than manually punching holes if you are working on a low-volume PCB project.
Number of Layers
Rigid-flex PCBs consist of several layers held together by adhesives. Generally, the higher the number of layers, the more complex the manufacturing process.
Consequently, the higher the manufacturing cost, the better the equipment to ensure the board works well.
FAQs
How can you reduce Rigid Flex PCB cost?
Reducing the cost of a rigid-flex PCB takes special consideration as each material plays an important role.
Sacrificing one for a cheaper alternative means losing some qualities of the board.
Regardless, here are some ways to spend less manufacturing your circuit board.
First, choose cheaper materials that reduce the overall cost, such as FR-4, rather than the costlier polyimide.
However, before doing so, consider the board’s application requirement and electrical properties first.
Second, use standard tools rather than customized ones to lower the overall cost.
Third, use panelization to reduce material wastage, manufacturing time, and tooling costs.
Fourth, you can choose a reliable manufacturer that can suggest design changes to minimize the rigid-flex PCB’s cost.
What are the cost differences between a flexible and rigid PCB?
Generally, flexible PCB materials and manufacturing are costlier than rigid PCBs.
For instance, polyimide, a substrate material in flexible PCBs, is costlier than rigid PCBs’ FR-4 material.
But that’s a general observation, as some rigid PCBs are costlier than flexible PCBs.
The reason is that special-purpose rigid PCBs for robotics cost more than flexible mobile phone PCs.
In summary, the cost of a PCB depends on its size, materials, manufacturing processes, complexity, and production volume.
Which PCB materials reduces manufacturing cost?
Before opting for a cheaper material, consider your board’s electrical and mechanical properties.
Generally, the lower-cost options are inferior electrically and mechanically compared to the more expensive alternatives.
But if you don’t mind, you can choose FR-4 or CEM-1, as both have similar properties.
Additionally, consider metal core PCBs that use metal substrates like copper instead of FR-4.
They are cost-effective alternatives for applications that require high-density circuitry.
Lastly, use paper-based PCBs for low-power applications if you work on a circuit board.
The major downside is that they are not as durable as all the other alternatives.
Conclusion
A majority of rigid-flex design aspects contribute to the higher price of the board.
Therefore, knowing the areas you’ll change to lower its overall cost is important.
But doing so can sometimes be dangerous as you’ll affect its structural and electrical properties.
Additionally, using cheaper materials will shorten its lifespan, especially when you use it in a high-demand application.
Be careful; sometimes, manufacturing PCBs cheaper will cost more in the long run as you’ll spend more on maintenance.