Polyester Dome Facts
Polyester is an overlay of choice because it is more durable than switches with overlays made from other types of materials, such as polycarbonate. Polyester especially is a good choice if your application has more than 50,000 actuations; in fact, life cycle tests show that polyester may be actuated more than 1,000,000 times in a tactile switch without showing signs of wear. If you are looking for appropriate levels of tactile feedback in your membrane switch, make sure your overlay thickness is between .006 and .010.
In the case of polyester dome (also known as “polydomes”) silver flex membrane switches, the tactile response is achieved through the use of polyester domes that are formed either in the circuit or in the graphic overlay layers. Changing the diameter and height of the polydome when constructing the polyester dome silver flex membrane switch will affect the dome’s actuation forces. It’s important to note that polyester dome membrane switches are much quieter than their metal dome counterparts, so they are often used in sensitive environments including hospitals and recording studios.
Polydomes often are formed into the top circuit of membrane switches. As polydomes require expensive machined tools that typically are built specifically for each design, they become more cost effective as volumes increase because they do not require individual assembly. Generally, polyester domes are an economical choice if the order exceeds 1500 domes.