Engraving In this labour intensive process the keycaps are engraved with the required symbol, then inlaid with ink. Only used for small volumes. Laser-printing Legend inserts This method of legending can be recommended when complete industrial keyboards are required in different keyboard layouts for which Rafi will develop the respective soft- ware. The keyboards can then be legended within a short time. This method of legending ist particularly recom-mended for average to large volumes. In the case of keycaps with replaceable legend inserts it is possible to print or engrave the legend inserts. As these insets are protected by the lens, there can be no abrasion here either. Contact principle – Mechanical (M): All keyswitches can be flow-soldered, provided that anacid fluxer is used and that the whole unit is cleaned af- terwards in de-ionised water. Cross contact (RS 76 M)Bridge contact (RS 76 M, illuminated) There are two contact principles: – Contactless (C): Based on Hall-IC (RS 76 C) Cleaning Soldering Keyswitches should not be washed in freon or similar substances as a lubricant is used, otherwise the operatinglife of the keyswitches will be reduced.If complete keyboards are to be cleaned by dipping, it must be remembered that they keyboard may only be dipped in the dipping solution as far as the component side of the PCB.Keycaps can be legended by different methods: The soldering temperature should not exceed 250 °C, the soldering time not be longer tahn 3 seconds. All RS 76 C-keyswitches can be soldered in solder bathes. The assembled PCB should be cleaned only by using brushing machines from the soldering side ot the PCB. The cleaning agend should not exceed the component side ot the PCB.

RS 76 full-travel keyswitches

Two-shot moulding The Rafi full-travel keyswitches RS 76 are modular systems for designing individual key blocks and keyboards in the 3/4 inch (= 19.05 mm) grid. Using this method the symbol is separately manufactured from a plastic and then the appropriate keycap form is moulded round it. Advantage: The character becomes a integrated part of the keycap, thus eliminating abrasion. All Rafi keycap sets with standard legending are manufa-tured by this method.Customer specific two-shot moulded keycaps on request. Printing Keycaps can be printed with a two-component ink on request. The abrasin of this kind of legending is high. This method of legending is suitable for average volumes. DefinitionsMomentary keyswitches Momentary keyswitches return to their initial position af- ter being pressed (momentary action). Latching keyswitches Latching keyswitches lock when actuated and are retur- ned to their initial position when pressed again (push-push action). Keycap materials Keycap, n-module Keycap without legend insert: ABS Keycap with legend insert: – Keycap body: ABS – Lens: PC A 2-module keycap f. ex. has the twofold length of a 1-module keycap.

Legending of keycaps

4

RS76

4 - 120PCB Keyswitches