semi flexible pcb
semi flexible pcb

Semi Flex PCB

Semi Flexible PCB – Rigid PCB with certain flexibility capabilities

Rigid and PCB flexível are two common circuit types, but they can’t meet the demands of all applications. To address this issue, PCB rígido-flexível has emerged. However, they might not always be the best choice, especially in projects with limited budgets or high mechanical stability requirements. In such cases, FS Tech recommends considering the use of semi-flex or semi-rigid PCB.

The goal of semi flex PCB is similar to that of rigid-flex PCB, which is to provide a certain level of flexibility while meeting rigidity requirements. However, unlike rigid-flex PCB, semi flex PCB is manufactured using conventional methods and then thinned in the areas where flexibility is needed, typically using deep milling techniques.

Ordering Semi-Flex PCB From FS Tech

FS Tech is a PCBA company based in China, specializing in providing a wide range of PCBA solutions, from design to assembly, offering a one-stop service. With 20 years of development, we have earned high praise from numerous domestic and international customers. In the field of bare board manufacturing, we are committed to providing various types of circuit boards, including semi-flexible PCBs, at lower prices and higher quality for our customers. So why choose FS Tech over other manufacturers?

  • Made in China: Semi-flex PCB is often seen as an alternative to rigid-flex PCB, and one significant aspect is price competitiveness. As a Chinese manufacturer, we fully leverage the advantages of labor and material costs to ensure that the semi-flexe PCB we provide are more cost-effective than those from European and American manufacturers.
  • Transparency: Unlike brokers, FS Tech has its own manufacturing and assembly facilities, and we welcome customers to inspect anytime. If conditions allow, we encourage customers to visit China, have face-to-face discussions with us, and create a more open and transparent environment for cooperation.
  • Professional Service: What FS Tech takes pride in the most is our meticulous customer service. Whether you are collaborating with us for the first time or a returning customer, we strongly recommend you get in touch with us via email. Our service starts from the initial contact and continues until the project’s completion, covering our sales team, engineering team, and procurement team, providing comprehensive support for your project.

Why Semi Flex PCB

AspectSemi Flex PCBRigid flex PCB
DefinitionEssentially a rigid PCB that is made thinner through deep milling technology to provide flexibility.Flexible circuits serve as connectors for rigid circuits and provide the bending properties required by electronics.
FlexibilityLess flexible and has a small amount of bending properties but cannot be folded.Highly flexible and suitable for various three-dimensional space structures and small electronics.
MaterialMost commonly used material for the main body is FR-4, and for some high-power applications, metal substrates such as aluminum or copper can be used.Rigid part is still usually constructed of FR-4, while the flexible part uses flexible materials such as polyimide (PI) or polyester film.
StiffenerAlready sufficiently strong and does not require the use of reinforcing Stiffeners.Choose according to the application needs, such as aerospace, medical or military applications that require high reliability.
LifetimeBelongs to static bending, and the bending capacity of the flexible part usually does not exceed 3 times, otherwise it will face the risk of fracture.Although a mainstream option, flexible sections are susceptible to physical damage or fatigue issues caused by bending.
Space EfficiencyThe fit is better than rigid PCB, but it cannot be compared with flexible or rigid-flexible PCB.Extremely friendly for optimizing product volume, especially for three-dimensional internal spaces.
CamadasBecause it is a rigid board, there are not many restrictions on the number of circuit layers.There may be some limitations to multi-layer construction due to limitations of flexible circuits.
Process ComplexityUsing the traditional Processo de fabrico de PCB only requires adding additional deep milling technology, which is relatively simple.The connection and conversion of different parts require the addition of technologies such as pressure-sensitive conductive adhesive and flexible connectors.
Application AreasMore suitable for low profit or cost sensitive applications.Considered an essential component in various high-end applications.
CustoAs in the previous comparison, semi-flexible PCB is not comparable to rigid-flexible PCB in all aspects, and its existence is more due to low cost.Whether in terms of materials, manufacturing processes or technology considerations, rigid-flex PCB is definitely a more expensive circuit board type.

Semi Flex PCB Manufacturing Q&A

The substrate material affects flexibility, durability, signal interference, etc. Therefore, it is recommended that designers conduct in-depth research on the project to understand the specific needs before making a choice. Based on better cost performance, FR4 is often the material of choice for semi-flexible PCB.

Use bend-friendly design instructions and methods, such as gradual bends, rounded corners, and precise trace spacing, to ensure the board can bend without damaging the traces.

Material thickness variations can lead to stress concentration, signal integrity issues, and component mismatch. It is advisable to choose materials with controlled thickness tolerances and collaborate with reputable manufacturers to ensure material inspection before manufacturing and quality control after production.

Establishing appropriate guidelines to optimize the plating process, it is recommended to use advanced plating methods such as pulses to obtain a smoother and uniform plated surface. Carry out necessary inspections on the plating area at the end of the process.

An electrostatic adhesive layer is typically used to ensure the adhesion of multiple layers in a PCB, providing structural integrity. However, they are not always necessary for standard applications. On the other hand, if your project involves sensitive components, you may consider adding an electrostatic bonding layer to the surface or bottom of the PCB during the design phase.

Further Reading: How to deal with sensitive components in PCBA?

Get a Semi Flexible PCB Quote