How are EMI Shielding Gaskets Manufactured?

fabric over foam shielding gasket

As technology becomes more pervasive, the amount of electromagnetic radiation in the environment increases as well. These radiated energy waves disrupt the performance of electrical gadgets and equipment, and in the worst case scenario, cause a breakdown. The theory of EMI shielding was born out of the need for preventing devices from emitting electromagnetic waves or being affected by the interference caused by this radiation. From wire mesh gaskets to fabric over foam variants, different kinds of EMI shielding solutions exist in the market to fulfill the diverse needs of electronic companies. Now, EMI shielding manufacturers employ extensive construction processes based on the gasket application, but for the purpose of our discussion, we will explore the four most popular methods below:

1. Die-Cutting

One of the biggest advantages of the die-cutting method is the level of precision it affords gasket manufacturers. This fast and repeatable solution allows manufacturers to produce anywhere between five and 50,000 gaskets effectively simply by figuring out the required specifications. If your product design includes fasteners, the die-cutting process allows for punching slots or holes of specific radii in addition to supporting nested parts.  Some die-cut gaskets are equipped with a conductive PSA (pressure sensitive adhesive) backing, which makes controlling liquid adhesives easier on the assembly line. Such gaskets are readily available, and they have short lead times of two to four weeks.

2. Extruded Gaskets

Perfect for groove and flange applications, extruded gaskets are available in various profiles, including solid and hollow O, U, E, P, D, hollow and solid square. Any product that needs a semi-standard gasket shape can work with manufacturers of extruded gaskets to personalize the required shape. In fact, these components can be imparted with innovative press-fit and anti-stretch features.  Following extrusion and curing processes, the gaskets can be cut according to the exact specifications to form full EMI shielding enclosure seals. Extrusion comes in handy when the manufacturer wishes to utilize costly shielding substances to their optimum level. For EMI shielding, extrusions are created using a thin exterior layer of conductive silicone, thereby decreasing the amount of silver or nickel graphite considerably.

3. Molded Gaskets

Some manufacturers prefer to create custom molds that perfectly conform to the design requirements of the products. This eliminates the center drop waste normally associated with die-cut processes and cuts cost effectively. So, if you’re using materials that are comparatively costlier than regular silicone gaskets but need to accommodate a fixed budget, this is the perfect solution for you. Molded EMI shielding gaskets are capable of solving multiple issues that cannot be addressed using die-cut or extruded gaskets.

Unlike extruded or flat gaskets, molded gaskets enable manufacturers to conform to three-dimensional designs. However, this level of flexibility is offset by longer lead times and higher tooling costs. Custom molded gaskets can also be produced quickly and accurately as automation options are available, especially in volume applications.

4. Displaced Gaskets

Also known as form-in-place gaskets, displaced gaskets are used to keep EMI radiation away from electronic products. This method relies on dispensing machines to load the thin gasket shelves with a precise string of electrically conductive silicone, leading to a 30 percent reduction in compression force, greater PCB area, reduced material consumption, apart from high quality shielding properties. With form-in-place gaskets, you get efficient material consumption and automated dispensing methods – both of which are highly useful when creating complex gasket designs. Because of the elimination of manual gasket placement, more compact shapes can be created. Displaced gaskets are in great demand as they can accommodate densely populated electronic packaging easily, especially when complex cross-section patterns and isolation are a must. Other benefits range from the lack of assembly to adhesive-less application, improved flexibility for gap closure, and minimum scrap material output.

Gone are the days when electrical engineers would make do with fabric over foam shielding gaskets or wire mesh gaskets. Countless options are available in the market with new varieties being introduced on a regular basis. So, whether you want to procure fabric over foam shielding gaskets or wire mesh gaskets, research the EMI shielding sector to find out the latest offering in the market. This little effort will help you make an informed decision regarding the EMI shielding gasket that fits their needs the best.

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