Graphic Overlays
The graphic overlay or nameplate can be used to efficiently customize and identify your product. A broad range of materials and processes can be incorporated to help make your products unique. Graphic overlays are commonly used to show corporate logos and to identify or instruct users on the product features. Another common use of graphic overlays is to depict keypad locations when used in conjunction with mechanical switches.

Graphic Overlay Material Selection
The proper selection of a graphic material is critical in order to ensure that you will attain both the appropriate aesthetic qualities of the part as well as maximize the longevity of the final product.

Polycarbonate comes in thicknesses of .005"-.030" thick, while polyester comes in thicknesses of .005"-.010". Each can be purchased in the following finishes: gloss, mattes (various levels), and textures.

Though the materials look very much the same, polyester possesses greater resistance to chemicals than does polycarbonate. Also, polyester has much greater resistance to fatigue in applications requiring the graphic overlay material to flexed.

Graphic Design and Preparation
• Blueprints - Provide drawings that clearly dimension all physical characteristics including color breaks and copy.
• Colors - Identify colors by using Pantone (PMS) color number or a color sample. It is important to supply the exact standard for which our color match will be evaluated. Be cognizant of how colors contrast with one another in order to maximize the legibility of the text and symbols.
• Background - Dark backgrounds and light text will provide greater clarity and show less wear and dirt.
• Artwork - It is possible for customers to supply useable artwork, but they should consult SSI first to ensure that proper artwork specifications are met.
• Borders and Outlines - Avoid outlines close to cutouts or outer edges, or circles within circles, as any misregistrations will be visually accentuated.
• Text - Block lettering provides the most legible copy. Try to use common fonts. When logos or symbols are used, it is best to supply film positives or accurate black and white artwork for SSI to scan. Positive letter strokes should be a minimum of .008" and .012" for negative letter stroke.

Embossing of Graphic Overlays
Raising certain areas of the graphic overlay can offer a unique look to your product as well as provide an important function.

SSI can emboss graphics in two ways: hard-tooled emboss and print emboss. As the name implies, hard-tooled emboss utilizes male and/or female dies to form the graphic overlay in a variety of shapes and styles. Common hard-tooled embossing types include:
In the case of a ring emboss, borders are usually raised .005" to .015" high and .040" to .070" wide. The maximum emboss height is typically limited to 6 times material thickness of polycarbonate. Embossed corners should have a minimum of .010" radii.

Print emboss, on the other hand, is a tool-less process involving printing multiple passes of ink to build up certain shapes on a graphic overlay. This option works best with the ring style or embossing detailed graphic entities. Among the advantages of print emboss is the elimination of stress on the material often caused by the forming process. Better adhesion to the sub-layer is achieved because the graphic stays flat. Print emboss height is limited to .006"-.010".

Adhesive Selection
A wide variety of pressure sensitive adhesives are available to bond the membrane switch to a substrate. Selection of the best adhesive will depend on such factors as environmental conditions, type of substrate (surface energy) and smoothness of the surface. In general, low surface energy materials as well as rough surfaces provide more difficult substrates for which to adhere.

Please contact SSI Electronics for additional information on graphic overlays or for a quotation on your project.