Holland Membrane - Manual (Page 2)

2
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