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What is a Computer keyboard made of?

What is a Computer keyboard made of?
ABS or PBT keycaps over either a silicone rubber dome on printed film, or individual mechanical switches.

The keycap plastic explains most of the visible ageing: ABS is a softer polymer that polishes under fingertips into the shine familiar from any old keyboard, while PBT keeps its texture much longer. Legend printing matters as much — pad-printed legends rub off, laser-etched ones fade, and doubleshot caps have the legend moulded as a separate piece of plastic that cannot wear away because it goes all the way through. Membrane boards fail as a unit when the printed traces crack or a spill bridges them; mechanical boards fail one switch at a time and can be repaired, which is the practical argument for them beyond feel.

Component by component

Every material is a choice, and the third column is the constraint that drove it.
Part Material Why that material
keycaps ABS, or PBT in better keyboards ABS is cheap and takes sharp legends but develops a greasy shine within a year; PBT is harder, more textured and resists shine.
membrane mechanism silicone rubber domes over three printed polyester sheets with carbon traces The whole switching layer is three films and a rubber sheet, which is why a membrane keyboard costs a few pounds to make.
mechanical switch a nylon and polyacetal housing with a spring and gold-plated crosspoint contacts Each key gets its own switch with a defined force curve and a 50-100 million press rating, which is what the price buys.
stabilisers wire and plastic inserts under wide keys Without them a space bar pressed at one end binds; they are also the usual source of rattle in a mechanical board.
plate and PCB steel or aluminium plate over a printed circuit board with a matrix and diodes The diodes are what allow N-key rollover — without them, three simultaneous keys can register a phantom fourth.

Other electronics objects

Common questions

What is a Computer keyboard made of?
ABS or PBT keycaps over either a silicone rubber dome on printed film, or individual mechanical switches.
What is the keycaps of a Computer keyboard made of?
ABS, or PBT in better keyboards. ABS is cheap and takes sharp legends but develops a greasy shine within a year; PBT is harder, more textured and resists shine.
What is the membrane mechanism of a Computer keyboard made of?
Silicone rubber domes over three printed polyester sheets with carbon traces. The whole switching layer is three films and a rubber sheet, which is why a membrane keyboard costs a few pounds to make.

Related pages

Sources

  1. Typical range compiled from manufacturer specifications — At One Place

How these figures are compiled and checked