What is silver migration and why is it important for your keypad?

Are you building a product that might be exposed to moisture or used in a humid environment? You’re probably wondering what choice of membrane switches you should consider to counter the adverse effects of moisture on the electric circuits of your application.

But before we jump into the solution, let’s examine the problem in detail. Why does moisture pose a threat to the smooth operation of devices based on electronics and PCB assemblies?

Silver migration is at the root of this problem. What is it and how do manufacturers protect electronic devices against it? Read this article to find out.

What is silver migration?

When membrane switch traces are exposed to moisture, silver migration might happen. It’s the electrical short caused by the ionic migration of silver between two neighboring traces. 

We have observed this phenomenon in a wide range of products and markets, most notably printed electronics, microelectronics, modules, PCB assemblies, and membrane switches.

How to eliminate silver migration? Case study

A few months ago, we were approached by a client who struggled with problematic product operations. The product in question was a skincare device used in environments characterized by moisture.

Our client requested that Melrose engineers investigate the components that contributed to the product’s failure.

Our team discovered that the development of crystalline dendritic structures allowed the conductive silver traces to scatter over the conductive silver membrane switch tracks. This is silver migration.

Our engineers dyed the unit by submerging it in a shallow water bath. Moisture was entering the device from the point where the membrane switch tail reached the housing as the device, according to the direction of the colored water. Instead of a full gasket around the component circumference, the product used a “tail filler.”

Our solution? A high-quality gasket

 Our engineers suggested a temporary fix for the issue in the form of RTV silicone adhesive added to the tail escape site during assembly. 

The construction of a completely sealed membrane switch gasket was made possible by the use of next-generation plastic molds.

We solved the problem and offered a recommendation for the future to ensure that the product delivered the best user experience.

Get reliable membrane switches from Melrose

With our assistance, you can build a personalized membrane switch solution for your goods. Our membrane switches are designed to have a unique user interface as well as an outer skin for appliances and machines. 

From medical and military to aerospace and automotive, our expertise will combine components and build approved panel assembly solutions for the most challenging environments.

Get in touch with us and secure a high-quality component for your product.


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