Mechanical Keyboard Keycap Material Technology – ABS, PBT, POM

Types of Keycap Materials

– ABS: A synthetic resin. ABS is a terpolymer composed of acrylonitrile, butadiene and styrene. A represents acrylonitrile, B represents butadiene, and S represents styrene. The melting temperature is 217~237 ℃. In addition, the hardness and toughness of ABS can be changed by adjusting the proportion of the three components. Shrinkage is 0.4%~0.9%
– PBT: A kind of plastic mainly composed of polybutylene terephthalate, known as white rock. Melting temperature: 225~275 ℃, 1.7~. 2.3%. There is still a little shrinkage (0.05%) within 48 hours after molding.
– POM: Polyoxymethylene resin, commonly known as Saigang, super steel, with properties close to metal.

Most Commonly Used Materials For Mechanical Keyboard Caps

– Raw material cost: ABS ＜ PBT ＜ POM
– Wear resistance: ABS ＜ PBT ＜ POM
– Touch: ABS has the softest touch compared with PBT and POM due to its material characteristics, and is most suitable for long-term typing.

PBT is more wear-resistant than ABS, but the touch of PBT is harder than ABS, and the surface particles are larger. Good PBT feel can be very delicate and smooth, but still has a frosty feeling.

POM is the most wear-resistant of the three materials. The material itself is black. The lettering method is limited to radium carving and etching, and the cost of pure materials is the highest. Only Cherry and other manufacturers use POM as the original keyboard cap. Compared with ABS and PBT, the tactile feeling is smoother, cooler, and the surface is similar to a smooth surface. Moreover, POM has a sense of percussion on Cherry’s tea shaft and green shaft without steel plate. The sound is not dull, and it is very comfortable. The only disadvantage is that the radium engraving is easy to blacken or even wear.

Keycap Lettering Method

Laser Etching

The so-called laser etching is the use of laser lettering technology to burn black grooves on the key cap. Cherry G80-3xxx and G80-18XX series white and black keyboards are common.

Advantages: Low cost, relatively clear and firm handwriting. Moreover, it is environmentally friendly and will not produce harmful substances.
Disadvantages: The handwriting is blackened or even worn, and the color is single

Screen Printing
The principle is to cover a special screen on the blank keyboard, where the handwriting is hollowed out, and then scrape the ink over it, so that the hollowed out part will be printed with handwriting.

The feature of screen printing is that after printing the handwriting, a special screen can be brushed with a layer of plastic, which will form a layer of plastic protective film covering the printed handwriting when it dries up, which can prevent the abrasion of handwriting caused by long-time use. The delicate hand feel of filco’s skin like coating is also commendable. At the same time, the coating is easier to wear. The dual-mode filco is changed to be manufactured in Mingzhe, Taiwan, China Province, China. The coating increases the particle feeling to increase the wear resistance. In fact, it is less delicate than the old coating.

Filco first generation and second generation keyboards are common.
Advantages: The handwriting is protected by coating, and the feel is delicate and comfortable
Disadvantages: The coating is very easy to wear, and the handwriting is easy to turn black after the coating is worn

Immersion Printing, Thermal Sublimation

Immersion printing is a printing method different from ordinary ink printing. It uses solid resin ink instead of common liquid pigment ink. This kind of ink will sublimate into gas under high temperature, and sublimate after penetrating into the surface of permeable printed materials in the form of gaseous molecules, thus becoming a whole with the printed surface on the physical level, rather than just “sticking” to the printed surface like ordinary pigment inks, so its printing fastness is extremely high.

Cherry’s old keyboard is common
The thermal sublimation PBT of Cherry’s old keyboard is made of BSP. Because the dye sublimation of the thermal sublimation itself pollutes the environment, the thermal sublimation of BSP has stopped production, and only the keycaps without engraving are sold. The surface of BSP is fine and smooth, which is almost the PBT key cap closest to the touch of ABS surface.

Advantages: It is almost the most wear-resistant engraving method for PBT keycaps, and many details can surpass the two-color keycaps. For example, the gradient of win98 in the above figure can be made lifelike by thermal sublimation. Even GMK and SP are difficult to make two-color molds.
Disadvantages: Compared with two-color molding, the disadvantages are that the color is less, and the production has stopped due to environmental pollution. Cherry once wanted to replicate the PBT sublimation of BSP, but stopped because of the pollution problem.

Two-Color Molding

Two-color molding is to use molds to combine two different colors of plastic, and use the difference of two plastic colors to display fonts.

Advantages: Two color forming has the advantages of bright font color, high durability, and difficulty in dropping characters. If the manufacturing technology is good, the touch performance of keycaps will be very good; The section is as shown in the above figure. The first one is SP PBT bicolor, which is crisp to use, while GMK and SP ABS bicolor are very flexible and soft.

Disadvantages: It is difficult to show fine characters, the color variety is monotonous, the stroke complexity is low, and the fixed cost of its manufacturing is expensive. Due to its high cost and non wear resistance, the current keyboards rarely use two-color molded keycaps. Only Cherry’s old keyboards can use them. The latest two-color is G80-1869.
Now the two most important manufacturers of two-color keycaps are GMK in Germany and SP in the United States. The latter produced DCS high two-color key caps, and also produced DSA and SA low and high two-color key caps.

Touch: Compared with PBT, two-color ABS has a more delicate and soft feel. The two-color key caps of GMK and SP are more wear-resistant than many ordinary ABS. The two-color PBT is mainly due to the problem of the PBT material itself. The shrinkage is greater and the quality control is more difficult to control. At present, only Taihao and ikbc have a set of two-color PBT, and the feel is different.

Height: In fact, the original height of GMK and the DCS height of SP are the most suitable for various shafts. These two heights are the most common for four common shafts and rare shafts. The difference is that GMK is thicker and the DCS of SP is thinner. GMK is softer and DCS is relatively crisp, which is suitable for some sections of the shaft. SA height has a unique feeling when typing on the paragraph axis. DSA height feels better on linear axis.

In a word, ABS material is undoubtedly the best choice for users with high requirements on hand feel and light transmittance, while PBT material is more durable.