Rubber Membrane Keypad Design Considerations

Know Your Options

Enhance the look and feel of your device while making the user experience intuitive. Rubber keypad, rather than a standard polycarbonate overlay, is a great way to enhance the interface. Design it exactly how you want it.

Contact Material

The contact materials used will define the life you can expect.

  • Printed carbon elastomer: ≥ 1 million cycles typical

  • Carbon puck elastomer: ≥ 3 million cycles typical

  • Printed silver membrane: ≥ 3 million cycles typical

Typically a carbon or gold/nickel plate over copper is recommended if the circuitry is on a printed circuit board. The carbon will have a higher contact resistance with improved immunity to extremely corrosive environments.

Rubber Keypad Resistance.png
Xymox-Design Specifications

Recommended Design Pattern:



Silk screen legend life will vary depending on key shape, style of the legend, and operating conditions. As a general guideline, a standard printed legend will meet 250,000 to 500,000 finger actuations (as simulated with a rubber test finger) before showing signs of wear.

To increase cycle life, overcoats can be added. This can increase the life to the equivalent of 1 million finger actuations.

Legend colors are typically matched to Pantone Colors with a tolerance of ± 1 shade. There are printing limitations on the distance between the legend and key edge:

  • Silk screen printing: 3mm minimum from key edge

  • Convex surface: 20mm minimum keytop radius

  • Concave surface: 30mm minimum keytop radius


Sharp tactile feel occurs with the right combination of actuation force, stroke, and rubber hardness. Sharp tactile can be obtained with 60 durometer silicone and a long stroke but as these factors are increased, keypad life decreases.

Using a half membrane switch or full membrane switch with a Metal or Poly Dome for tactile feedback, can provide sharp tactile feel while allowing for a lower overall profile than if the elastomer was designed to provide the tactile feedback.


The following dimensions will be required to design a custom rubber keypad:

  • Overall Keypad Length and Width

  • Key to Key Center X and Y Axes

  • Key Height

  • Keytop Length and Width

  • Mat/Base Thickness

Elastomeric Keypad Standard Tolerances