Reliable and cost-effective switch solutions with elastic tactile feedback and various finishes could achieve excellent abrasion resistance and backlight requirement.


Reliable and cost-effective switch solutions with elastic tactile feedback and various finishes could achieve excellent abrasion resistance and backlight requirement.

Produced by compression mold, silicone rubber keypad is now widely applied in high tech industries with its excellent durability, electrical insulation and weather fastness. Based on the client’s request, the tool maker would suggest suitable tooling cavities for the most economical and efficient solution.

The most distinct character of silicone rubber keypad would be its elastic tactile feeling created by different durometer and web area design combination. Color can be changed by adding pigments into the natural rubber, spray painting, silkscreen printing, or laser etching. Also, to protect the legends printing on it, there’re different methods to choose.

Silicone rubber keypad works with all kinds of circuit boards from membrane switch to PCB. Also, it could be co-molded with plastic or metal insert parts, or glued with plastic or metal keycaps.


Elastic tactile feeling
Excellent electrical insulation and weather resistance
Various decorating options
Lower tooling cost
RoHS compliance


Duracoat Series offers a sprayed polymer layer on silicone rubber keypad’s surface by vulcanization process at approximately 200 degree Celsius. This treatment could provide excellent key-top printing protection, reduce friction between keys and frames, and prevent dust adsorption by static electricity.

Reduced friction to prevent keys stock
Enhanced key-top printing protection
Excellent abrasion resistance
Glossy/ matte finish

To learn more for your application, please contact us
Encap Series provides clear, simulated plastic finish on rubber key top. With special surface treatment, the liquid polymer provides a dome-shape hard coating on rubber key top surface for graphic protection. Compare to the PlaS series, Encap is more economical option to catch all of the silicone rubber keypad and plastic advantages.

Simulated clear plastic finish
Protected keypad printing
Assembly cost savings
Excellent abrasion resistance
Excellent bond between silicone rubber and polymer
Hard/ Soft Encap
Glossy/ Matt Encap

To learn more for your application, please contact us
The BackLite Series has been developed in order to improve visibility in the dark as well as in daytime. It’s most suitable for illuminated requirement. With spray painting and laser etching process, the graphics can be with or without color. LED window can also be achieved.The BackLite Series is always combined with our Duracoat Series for the best reliability and distinctive finish.

Good light shielding on keypad surface
Superior visibility on graphics
Available for any key shape
Temperature range: - 40ºC ~ + 90ºC

To learn more for your application, please contact us
PlaS Series combines the injected plastic keycap and silicone rubber keypad. The graphics can be printed on plastic keycap’s surface or on rubber key top first and covered by clear plastic keycap. The keycap can also be glued with special adhesive which bonds the two complex materials well. PlaS Series combine all advantages of silicone rubber keypad and plastic together.

All key shapes available
Graphics on first or second surface
Assembly cost savings
Excellent bond between plastic and rubber

To learn more for your application, please contact us
Parylene Conformal Coating System (Qualify by Mil-I-46058C) provides a truly conformal protecting layer at key edges and corners. It’s completely pinhole free and strong resistances to solvent, acid and base.

Truly conformal coating without pinhole
precise thin film coating (0.2µm to 75µm)
Available to apply on any materials including flammable one
Superior resistance to temperature, moisture, chemicals, and electricity

To learn more for your application, please contact us


Abrasion Test

RCA Abrasion Wear Tester

 Silkscreen PrintingSilkscreen Printing (BLACK)Silkscreen Clear CoatSilicone CoatingDuracoatEncapParylene
Abrasion ResistancePoorFairGoodGoodExcellentSuperiorExcellent

1 cycle= 10,000 times of finger press.
Poor= under 10 cycles
Fair= 10 ~ 15 cycles
Good= 15 ~ 30 cycles
Excellent= 50 ~ 100 cycles
Superior= 100 ~ 200 cycles

Definition of failure
Failure occurs when a printed line breaks or a second layer of color is exposed.

Abrasion test equipment
RCA Abrasion Wear Tester: Norman Tool model #7-IBB.
Abrasion paper: Norman Tool paper type #1189

The above figures are for reference only. The result may be subjected to different font styles or graphics/ key designs. Joesmen reserves the right to change or modify the information without prior notice.

Design Recommendation

Design Guide 1

  1. Minimum distance from edge of keypad= 1.0mm
  2. Typical membrane dimension= key size + 2.5mm
  3. Typical guide hold spacing= 30-50 mm
  4. Minimum radius dimension= 2.0 mm
  5. Typical corner radius dimension= 1.0 mm
  6. Minimum key pitch dimension= 4.0 mm
  7. Minimum guide hole dimension= 1.5 mm
  8. Minimum distance from hole to membrane switch= 1.0 mm
  9. Minimum membrane spacing dimension= 1.0 mm


Design Guide 2

  1. Minimum clearance between bezel and keys= 0.3mm
  2. Minimum key pitch dimension= 4.0mm
  3. Typical conductive pill size= dia. 2.0-8.0mm
  4. Typical conductive pill thickness= 0.4-0.5mm
  5. Typical chamfer dimension= 0.5mm
  6. Typical chamfer angle= 45°
  7. Typical air channel width= 1.5~2.0mm
  8. Typical base thickness= 1.0mm
Force-stroke Curve

Force-stroke Curve


  • 1. Peak point
  • 2. Contact point
  • 3. Return point
  • 4. Return-peak point
  • F1= Peak force
  • F2= Contact force
  • F3= Return force (≧15g)
  • F4= Return-peak force


Click ratio= ( F1-F2) ÷ F1 × 100 %
Poor tactile feeling= Click ratio less than 0.50
Good tactile feeling= Click ratio higher than 0.50





Printing Guide

Minimum graphics thickness

  • Various printing colors are possible.
  • Best results with a flat-key top surface.
  • Could be printed positively or negatively.

Printing area & Graphics area

Concave shape & Convex shape



General Tolerances for Rubber Keypad

Actuation Force Tolerance Chart

Force (g)Tolerance
70 - 80+/-15 grams
90 - 110+/-20 grams
120 - 140+/-25 grams
150 - 180+/-30 grams
180 - 250+/-35 grams
250 - 350+/-40 grams

Dimensional Tolerance Chart

0 - 0.394+/- 0.0040-10+/-0.10
0.395 - 0.787+/-0.00610-20+/-0.15
0.788 - 1.180+/-0.00820-30+/-0.20
1.181 - 1.969+/-0.01030-50+/-0.25
1.970 - 2.759+/-0.01450-70+/-0.35
2.760 - 3.937+/-0.01870-100+/-0.45

Printed Legend Tolerance Chart

Line Thickness+/-0.003+/-0.08

Color Matching

Rubber: +/-15 Macadam Units per Spectrophotometer
Printing: +/- 12 Macadam Units per Spectrophotometer or 1/2 PMS shade under Macbeth Spectra Light

Rubber Hardness

+/-5 Durometer Shore A


Actuation Force (F¹)
The minimum force required to compress the switch to touch the circuit board so the action could be recognized.

Air Channel
Air path between switches to ensure the key can return to normal position after actuation. Normally design symmetrically for air release.

The sheet material forming the "apron" for all switches on the keypad. The base ties or connects all switches on the keypad.

The front panel (usually to be plastic or metal) that "egg crates" all rubber keypad switches and typically covers the base material of the keypad so it cannot be touched by human hands.

Click Ratio
The difference between the actuation force (F¹) and the contact force (F²) of a switch divided by the actuation force.


This "ratio" is extremely important when life is calculated and positive tactile feel is required in a keypad.

Conductive Pill
The current-carrying contact (silicone rubber impregnated with amorphous carbon) under each key completes electrical connection with the printed circuit board when the switch is actuated.

Contact Force (F²)
The force a switch typically realizes when contact is made with the printed circuit board.

Durometer means the hardness of switches and the base material (unless the keypad is a dual durometer keypad). The higher the durometer means the harder the material.

Also called travel distance. It means the distance from bottom of conductive pill (contact) to top surface of printed circuit board.

Resistivity shows how strongly a given material opposes the flow of electric current. The unit is normally expressed as ohm-centimeters.

The web area is the thin hinge between key and base that creates tactile feeling and stroke.