THE APPLICATION GUIDE is
an aid in the design and development of silicone keypads and specialty products. Silicone
combines excellent feel, reliability and long life in the most rugged environment.
Silicone keypads are used in a wide range of applications including medical, industrial,
instrumentation and communications equipment.
The Application Guide includes:
- Material and Processes
- Mechanical Tolerances
- Graphics Criteria
- Design Recommendations
- Drawing Information
- Terminology
![[keypad images]](images/appkeypad.jpg) Silicone material is
supplied to the keypad industry in two forms, liquid and gumstock. Liquid silicone is a
two part system mixed as it is used; gumstock is a one part system that has a shelf life.
Both are heat cured. Liquid silicone has the consistency of vaseline while gumstock is
more like putty or clay. Silicone is measured for hardness in a shore A scale. The lower
the number, the more silicone there is in the product and the softer it feels. The higher
the numbers the less silicone and the more filler there is in the product and the harder
it feels. Fillers can reduce elongation, compression set, tear and tensile strength.
There are less than a half dozen manufacturers of silicone. Si Tech uses GE materials
because of their UL listing, six sigma quality rating for consistency and traceability of
material batch runs.
Molding silicone rubber varies by process. The tools themselves are very similar and are
usually made from P20 steel or 6061 aluminum. Wear on the tooling is usually negligible
over the life of a project unless fillers that cause abrasion are added.
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The types of molding processes are liquid, compression,
transfer and extruding. Liquid molding is a closed loop system and molded under pressure
using computer controlled repeatable equipment. Compression molding is open-air system
similar to a waffle iron, material is hand cut and weighed. Transfer molding is a
combination of compression molding and gumstock material pushed into a mold under low
pressure. Extruding molding uses gumstock molding processes for continuous product such as
tubing.
Si Tech's team with over 75 years of experience in silicone keypad design and molding is
committed to providing complete customer satisfaction with the highest quality products in
a successful and timely manner. The customer is the focus of Si Tech's business.
Silastikey design options include:
- Custom Shapes and Surface Finishes
- Various Key Travel and Actuation Forces
- Wrap Around Designs
- Back Lighting, Light Pipes and Clear Windows
- Sealing Features
- Insert Molding
- Proprietary Silicone Coatings For:
- Abrasion
- Chemical
- Adhesive
- Conductive
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| Our Newport News, Va Manufacturing Facility |
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