Introduction
Membrane switch technology has become a reliable front panel solution where environmental concerns or frequent cleaning are an issue. The sealed nature of the technology coupled with its reliability and ability to offer tremendous aesthetic flexibility make it the solution of choice for many industries.
The success of any membrane switch design effort is greatly enhanced by effective communication between the design engineers and the membrane switch vendor. A mutual understanding of the technology and nomenclature is critical. This design guide is a tool to facilitate communicating those requirements.
Overlay Materials
A variety of overlay materials are used in membrane switch applications. Polycarbonate is a commonly used material because it is easy to print on, die cut and emboss – making it a very cost effective alternative. The disadvantage of polycarbonate is that it begins to show signs of wear sooner than some of the alternate materials. In most applications polycarbonate overlays will last a minimum of 100,000 cycles during life cycle testing. Uncoated polycarbonate is also susceptible to damage from a variety of chemicals. If a polycarbonate overlay is going to be in an environment that will subject it to chemicals, a hardcoat should be used to protect the overlay.
Polyester is a more robust material that has superior life cycle and chemical resistance properties. In life cycle testing, polyester shows no signs of wear at 1,000,000 cycles. However, polyester, due to its memory properties, frequently requires hydroforming rather than embossing. Hydroforming is more expensive for both tooling and unit cost. Polyester is also more difficult to die cut resulting in more frequent reblading of steel rule dies.
Both polyester and polycarbonate are available with a variety of textures and hardcoats. In their uncoated glossy form both materials are very susceptible to scratching. For this reason we recommend that gloss materials receive a hardcoat.
Material suppliers have developed specialty materials that offer some or all of the properties mentioned above. Appendix “A” lists many of the commonly requested specialty materials. For additional technical data or specific applications, please contact your Holland Nameplate sales engineer.
Artwork
Holland Nameplate offers complete artwork layout services. The customer should
2
