Keypad Graphics

All positive and reverse graphics are surface printedusing proprietary silicone inks that are cross-link bonded to the keypad during the curing process. Screening can be done on both sides of keypad when using clear silicone. Each graphic color represents an additional step in the manufacturing process. Also, Pantone numbers are used for specifying colors, but color chips can be matched.

Special attention must be given to keytop design when screening graphics on curved surfaces. Generally, the larger the curvature radius is, the better. Also, single curvature geometry is easier to print on than compound curves.

Digital Graphic Designs

Si Tech has the capability to accept graphic designs created with softwares like Adobe Illustrator, Corel Draw, Micrograph, Autocad and using several file type formats including:

  • * .cdr
  • *.eps
  • *.pdf
  • *.dwg
  • *.dsf
  • *.dxf
  • *.ai

centerfo_app4Recommended Graphic Parameters

Graphic Design

  1. Solid colors can be screened up to the edge of flat keytop.
  2. On curved keytops, solid colors can be screened up to 0.015″ to the tangent point of the outer radius.
  3. Distance from edge of the keypad to legend is 0.015″.
  4. Distance of matte legends to key is dependent on key height.
  5. Minimum line weight for legends is 0.007″.
  6. Minimum text height is 0.050″.
  7. Color consistency is within 1 Delta for production run.
    • Typical screening tolerances is 0.015″.

Keytops Considerations for Graphic Screening

  1. Minimum radius allowable for printing over the edge is 0.375″.
  2. On legend overun onto matte surface, a minimum transition radius of 0.010″ is required.
  3. Maximum curvature depth for concave keytops with a minimum radius of 0.375″ is 0.060″.
  4. Maximum curvature height for convex keytops with a minimum radius of 0.375″ is 0.060.


  1. Abrasion resistant: Si-Coat I / Si-Coat IV
  2. Chemical resistance: Si-Coat II
  3. Industrial Pre Coat Si-Coat 30
  4. Conductive: Si-Coat V
  5. Adhesive: Si-Prime

Typical Drawing Information

  • Overall Keypad Size
  • Keypad Mat Thickness
  • Keytop Dimensions
  • Mounting Hole Details
  • Mounting Boss Details
  • Radii Dimensions (keypad and buttons)
  • Key Spacing
  • Actuation Force (grams)
  • Material Specifications (durometer)
  • Legends & Color(s) (PMS numbers, etc.)
  • Keypad Color

For detailed information about our coatings, please request our individual brochures with all pertinent information including independent laboratory testing.

Additonal Information

If you required additional infromation our customer service and engineering department can be reach via e-mail at:, or by calling 757/887-8488 between 8:00am to 5:00pm EST.

Continue to our next Application Guide page: Terminology