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
|
Tactile
Response
F = Return
Force
A = Actuation force A = 350 grams
C = Contact force C = 230 grams
Snap Ratio = (A-C)/A) (350-230)/350=0.343)

|
Terminology
Actuation
Force: The force required to collapse the web of a rubber
keypad in conjunction with polydome, metal dome, mechanical switch
or rubber only.
Air Channel: Air path(s) on the bottom of rubber
keypads that allows for air passage when rubber is depressed.
Alignment Hole: Through hole in rubber keypad
that is used to position keypad in enclosure.
Base Matte: Silicone sheet material that joins
all keys on a rubber keypad. Also known as mat.
Bezel: The faceplate or cover, typically plastic
or metal, used to secure a keypad to a printed circuit board or
switch.
Bosses: Small posts used for positive alignment
of rubber keypad in bezels or assemblies.
Compression Set: The measurement of a material's
ability to recover its original size and shape after compression
under prescribed conditions.
Conductive Rubber: Silicone keypad impregnated/coated
with conductive material.
Color Matching: The visual and electronic analysis
of a mixed silicone rubber material compared to a supplied color
sample.
Diaphragm / Web: The thin hinged area that permits
a rubber key to flex.
Durometer: A measurement range of hardness for
silicone rubber.
Key Height: The measured distance from the bottom
of a keypad (base matte) to the top surface of a key.
Legend: Printed graphic (symbol, letter or number)
on the top of the rubber surface.
Life: The number of actuations realized before
the rubber diaphragm/web ruptures.
Reversed-Out Graphics: Graphics that allow rubber
color or masking color to be seen through top surface printing
on keypad.
Positive-image Graphics: Single or multi-color
printing on top of key surface.
Snap Ratio (A-C)/A: See graph
Stroke / Travel: Distance from the contact surface
of a rubber part to a surface.
Swell: The increase in volume of rubber when
in contact with petrochemicals for a determined period.
Tactile Feel: The response of rubber while depressing.
For tactile rubber keypads, it is a critical function of the diaphragm
web geometry.
Tear Strength: The tear strength is a measure
of the resistance of rubber to tear forces. The tear strength
is calculated by dividing the maximum force load by the thickness
of the rubber.
Wear or abrasion resistance: The resistance of
a particular ink or coating to manual wearing. The testing process
is usually a Norman tester with the number of cycles legends can
perform before wear is noticeable. |