1-800-890-6790 |

Design Guide for Membrane Switches

Flat Membrane
(Type FMK)

  1. Lowest cost
  2. Nominal actuation force: 4-12 ounces
  3. Actuation force tolerance: 3 ounces
  4. Minimal tooling costs
  5. Up to 10 million actuations
  6. Can be embossed (Key border only is recommended)
  7. Travel : .006" to .012" (micro- travel)

Poly Dome Membrane
(Type PMK)

  1. Definite "snap" when key is activated
  2. Nominal actuation force: 8- 24 ounces
  3. Actuation force tolerance: 4 ounces
  4. Up to 1 million actuations
  5. Full key emboss is recommended
  6. Travel : .020" to .030" (low- travel)

Tactile Graphic
(Type TGK)

  1. Definite "snap" when key is activated
  2. Nominal actuation force: 8- 20 ounces
  3. Actuation force tolerance: 4 ounces
  4. Tooling and unit price less than PMK
  5. While still providing tactile feedback
  6. Up to 1 million actuations
  7. Travel : .020" to .030" (low- travel)

Metal Dome Keypads
Metal Dome only (Type MDT)

  1. Crisp "snap" when key is activated
  2. Nominal actuation force: 10- 24 ounces
  3. Actuation force tolerance: 3 ounces
  4. Wide keys and space bars can be accommodated
  5. Travel : .015" to .025" (low travel)

Dome as Circuit Element
(Type MDC)

  1. Same features as Type MDT, but also has a printed Circuit Board which could carry a display or other electronic components
  2. Can also be used with a polyester lower circuit (with printed silver) to provide a lower cost version of the MDT

Cross section key for types FMK, PMK & TGK

  1. Overlay (polyester recommended)
  2. Upper circuit (polyester with printed silver)
  3. Circuit spacer (acrylic adhesive and polyester)
  4. Lower circuit (polyester with printed silver)
  5. Mounting Adhesive (acrylic)
  6. Tactile spacer (acrylic adhesive and polyester)
  7. Fully key emboss (recommended with tactile)
  8. Formed dome on upper circuit Formed dome on graphic

Cross section key for type MDT or MDC

  1. Overlay (polyester recommended)
  2. Dome retainer (acrylic adhesive and polyester)
  3. Dome spacer (acrylic adhesive and polyester)
  4. Upper circuit (polyester with printed silver)
  5. Circuit spacer (acrylic adhesive and polyester)
  6. Lower circuit (polyester with printed silver)
  7. Mounting adhesive (acrylic)
  8. Full key emboss (recommended with metal domes)
  9. Metal Dome
  10. Printed Circuit Board (with switch contacts)