BASIC KEYPAD DESIGN Rubber keypad design will vary with the functional and aesthetic requirements of the application. A designer may consider the options detailed in this section which show alternative key styles and the new possibilities for adding legends and backlighting to the design.
DESIGN CONSIDERATIONS Custom membrane switches shape and size can be designed so that almost any actuation force and tactile feel can be realized. Most applications require positive tactile feel with relatively long life, so an actuation force of approximately 125 150 grams is typically recommended with an accompanying snap ratio of approximately 40 - 60%. • • • • •
Features of Silicone Rubber Keypads: Multicolour designs easily accommodated Design-in of both Tactile and Linear feedback Translucent materials available Water and contamination proofable Cost effective
SILICONE MOLDING Molding is a repetitive process in which material is melted and injected into a mold cavity where the article is cooled down. After cooling, the mold opens and the finished/semifinished custom plastic parts are ejected. Molding is a process that is used for high volume parts, complex variable geometries, and when tight tolerances are required. The process of molding silicone rubbers is a very complex process, and involves much more variables than when dealing with thermoplastics.