Reliable and cost-effective switch solutions with elastic tactile feedback and various finishes could achieve excellent abrasion resistance and backlight requirement.
OVERVIEW
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.
CHARACTERISTICS
OPTIONS
Features
To learn more for your application, please contact us
Features
To learn more for your application, please contact us
Features
To learn more for your application, please contact us
Features
To learn more for your application, please contact us
Features
To learn more for your application, please contact us
BEFORE YOU START
RCA Abrasion Wear Tester
| Silkscreen Printing | Silkscreen Printing (BLACK) | Silkscreen Clear Coat | Silicone Coating | Duracoat | Encap | Parylene | |
|---|---|---|---|---|---|---|---|
| Abrasion Resistance | Poor | Fair | Good | Good | Excellent | Superior | Excellent |
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
Note
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 Guide 1
- Minimum distance from edge of keypad= 1.0mm
- Typical membrane dimension= key size + 2.5mm
- Typical guide hold spacing= 30-50 mm
- Minimum radius dimension= 2.0 mm
- Typical corner radius dimension= 1.0 mm
- Minimum key pitch dimension= 4.0 mm
- Minimum guide hole dimension= 1.5 mm
- Minimum distance from hole to membrane switch= 1.0 mm
- Minimum membrane spacing dimension= 1.0 mm
Design Guide 2
- Minimum clearance between bezel and keys= 0.3mm
- Minimum key pitch dimension= 4.0mm
- Typical conductive pill size= dia. 2.0-8.0mm
- Typical conductive pill thickness= 0.4-0.5mm
- Typical chamfer dimension= 0.5mm
- Typical chamfer angle= 45°
- Typical air channel width= 1.5~2.0mm
- Typical base thickness= 1.0mm
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
Poor tactile feeling= Click ratio less than 0.50
Good tactile feeling= Click ratio higher than 0.50
Minimum graphics thickness
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
| Inches | Tolerance | Millimeters | Tolerance |
|---|---|---|---|
| 0 - 0.394 | +/- 0.004 | 0-10 | +/-0.10 |
| 0.395 - 0.787 | +/-0.006 | 10-20 | +/-0.15 |
| 0.788 - 1.180 | +/-0.008 | 20-30 | +/-0.20 |
| 1.181 - 1.969 | +/-0.010 | 30-50 | +/-0.25 |
| 1.970 - 2.759 | +/-0.014 | 50-70 | +/-0.35 |
| 2.760 - 3.937 | +/-0.018 | 70-100 | +/-0.45 |
| >3.938 | +/-0.5% | >100 | +/-0.5% |
| Millimeters | Tolerance |
|---|---|
| 0-10 | +/-0.10 |
| 10-20 | +/-0.15 |
| 20-30 | +/-0.20 |
| 30-50 | +/-0.25 |
| 50-70 | +/-0.35 |
| 70-100 | +/-0.45 |
| >100 | +/-0.5% |
Printed Legend Tolerance Chart
| Inches | Millimeters | |
|---|---|---|
| Size | +/-0.006 | +/-0.15 |
| Line Thickness | +/-0.003 | +/-0.08 |
| Location | +/-0.010 | +/-0.25 |
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.
Base
The sheet material forming the "apron" for all switches on the keypad. The base ties or connects all switches on the keypad.
Bezel
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.
(F¹-F²)÷F¹×100%
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
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.
Stroke
Also called travel distance. It means the distance from bottom of conductive pill (contact) to top surface of printed circuit board.
Resistivity
Resistivity shows how strongly a given material opposes the flow of electric current. The unit is normally expressed as ohm-centimeters.
Web
The web area is the thin hinge between key and base that creates tactile feeling and stroke.