Standard vs. PCB switch: comparing membrane switches

Understanding the differences between two types of switches.

Switches are critical components in numerous electrical devices, and membrane switches have increased in popularity due to their reliability and versatility. However, there are different types of membrane switches—one of them being the PCB (printed circuit board) membrane switch. PCB membrane switches have been an increasingly popular alternative to standard membrane switches in recent years. But what exactly is a PCB membrane switch, and how does it differ from a traditional membrane switch?

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flex circuit used on membrane switches

Construction and materials

Typical membrane switch construction includes several layers of flexible materials, such as polyester or polycarbonate, that are placed on top of one another. A circuit is printed between the layers using conductive ink. In comparison, a PCB membrane switch is constructed around a copper clad PCB board. The most common substrate is the FR-4 (a fiberglass composite material) because of its strength, durability, responsiveness and, ability to be customized. This PCB acts as a rigid substrate, providing increased stability and resilience. Conductive traces are etched directly onto the PCB, allowing it to function as a switch when combined with the right overlay layer.

Mechanics

As described above, membrane switches consist of several layers that are separated by air. When you press a button on a standard membrane switch, you're essentially causing these layers to deform temporarily, allowing the conductive traces on the top and bottom layers to come into contact. This deformation creates the tactile feedback and registers the keypress.

In contrast, when you press a button on a PCB membrane switch, the actuation occurs by pressing the top layer down onto the PCB, where the conductive traces are etched. This direct contact with the rigid PCB ensures that the actuation force and tactile feedback remain consistent across the entire switch area. The rigidity of the PCB core also imparts enhanced durability and resilience.

Tactile feedback

Standard membrane switches can offer good tactile feel and feedback, but the actuation force and feedback can vary depending on the design and materials used (learn more about the addition of tactile domes and the history of the membrane switch from Machine Design). PCB membrane switches can offer more consistent and precise tactile feedback, since the rigid PCB ensures a consistent actuation force and feedback across the entire switch area. This makes them ideal for applications where precise control is critical.

Durability

PCB membrane switches may be more robust than standard membrane switches, but they’re still durable and cost-effective. They can withstand thousands to millions of actuations, depending on the quality of materials used, but can be susceptible to wear and tear over time. PCB membrane switches are known for their exceptional durability. The rigid PCB core provides structural integrity, making them capable of enduring millions of actuations, ensuring a longer lifespan and reduced maintenance requirements. For additional information, check out this article from engineering.com.

PCB switch sample in blue
Collage of standard membrane switches

Moisture resistance

Standard membrane switches can offer some level of water resistance, but this resistance is generally limited and depends on the overlay material and how the switch is sealed. PCB membrane switches tend to provide superior water resistance due to their rigid PCB core and the ability to achieve higher IP ratings. Manufacturers should carefully assess the specific environmental conditions and water exposure levels in their applications to determine which type of membrane switch is most suitable for their needs. When a water resistant switch is needed, PCB membrane switches are often preferred.

Design flexibility

Flexible design is a key feature of standard membrane switches. They can be made in various shapes and sizes, and with completely customized graphic overlays. are suitable for applications where aesthetics and design flexibility are important. Because of the rigid substrate, PCB membrane switches have some design limitations. However, they’re still customizable to a significant extent. Their design is best suited for applications where durability and consistent performance are the primary concerns.

Cost

Standard membrane switches are often more cost-effective than PCB membrane switches, making them a popular choice for budget-conscious projects. PCB membrane switches are typically more expensive due to the higher cost of materials and the manufacturing process. However, their extended lifespan and superior performance make them a cost-effective choice in the long run for applications that require durability.

Choosing between a standard or a PCB membrane switch

The choice between a standard membrane switch and a PCB membrane switch depends on the specific requirements of your manufacturing project. While standard membrane switches offer flexibility and affordability, PCB membrane switches excel in durability and consistent performance. By understanding the key differences between these two options, manufacturers can make informed decisions that align with their application's unique needs and performance expectations.

Looking for the right membrane switch manufacturer to support your next project? NMG is renown for its product engineering design solutions that work for you. Contact us today!

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