Materials Used in Keycaps Keycaps are commonly composed of one of two types of plastic: ABS (Acrylonitrile Butadiene Styrene) or PBT (Polybutylene Terephthalate). ABS is more frequent since GMK, the major keycap manufacturer, uses it, while PBT is gaining favor as the material of choice with newer profiles such as KAT and MT3. Both plastics are highly resistant to corrosion from chemicals and water. There are two main methods used for manufacturing keycaps: CNC (Computer Numeric Control) cutting and hand-layup. The former is used by most high-end manufacturers whereas the latter is preferred by some smaller companies. Hand-layup requires that each key be created by hand which makes automation impossible. However, since this process is very time-consuming, it provides an opportunity for small manufacturers to sell many keys at a time. The quality of a keycap depends on the manufacturer but also on the production method they use. With CNC cutting, there is less control over the end result since the machine can only cut specific shapes that you tell it to cut. This means that variations may occur from piece to piece. On the other side, hand-layup allows for much more freedom in designing your keyboard but the results may not be consistent from person to person or even between batches made by the same person. ABS is a thermoplastic polymer that is mixed together with styrene monomer in a factory and then molded into various products.