Several materials commonly used in computer keyboard key switches

Conventional keyboards have mechanical keys and capacitive keys. There is also a keyboard with a light touch membrane key in the keyboard of the industrial computer - only suitable for special occasions. The mechanical keyboard is the earliest structure adopted. Generally, it is similar to the principle of metal contact switch to make the contacts turn on or off. The advantages of mechanical keys are long life, consistent and unchanged feel after long-term use, and excellent button feel.
The common materials of computer key switches are HIPS, PC, ABS, ABS+PC, PBT, POM.
ABS material is the most common material with very good plasticity, suitable for the production of high-precision special-shaped parts, such as the daocherry switch itself (except the cross column is a special low-friction coefficient material), two-color keycaps, suitable for low-cost mass production production;
PBT material is not commonly used because of its high price, but it has excellent physical and chemical properties. The biggest feature is wear resistance and good flexibility. It is usually used for toothbrush bristles, but it is more luxurious to use on keycaps .
POM's keycaps have been used by cherry. POM is generally called Saigang in China, which means that it can be comparable to steel. Of course, he is not as good as steel. However, on special occasions, His superiority is reflected, ultra-high hardness, ultra-low damping, excellent heat resistance, excellent corrosion resistance, outstanding wear resistance.

HIPS: High Impact Polystyrene
HIPS is one of the cheapest engineering plastics. Compared with ABS, PC/ABS, PC, the gloss of the material is relatively poor, and the overall performance is relatively poor. HIPS is modified by PS plus butadiene, because The impact strength of PS is very low, and the products made are very brittle, while the toughness of butadiene is very good. After adding butadiene, the impact performance of PS can be improved by 2~3 times. Although the impact strength of HIPS is higher than that of PS It is much higher, but its comprehensive performance is still inferior to ABS, PC/ABS, etc. The impact performance of HIPS is relatively low in engineering plastics.

PC: Polycarbonate (Polycarbonate) abbreviated as PC is a colorless and transparent amorphous thermoplastic material.
Polycarbonate is a common everyday material. Due to its colorless transparency and excellent impact resistance, daily common applications include optical discs, eye lenses, water bottles, bulletproof glass, goggles, bank bulletproof glass, headlights, etc. Polycarbonate was also used to make the helmet visors of astronauts on the moon. Apple's iPod music player and ibook laptop case are also made of polycarbonate.

ABS: chemical name: acrylonitrile-butadiene-styrene copolymer, English name: Acrylonitrile Butadiene Styrene (ABS) ABS resin is currently The polymer with the largest output and the most extensive application, with excellent mechanical properties of toughness, hardness and rigidity.
Features:
1. Good comprehensive performance, high impact strength, chemical stability and good electrical properties.
2. It has good fusion with 372 plexiglass and can be made into two-color plastic parts, and the surface can be chrome-plated and painted.
3. There are high impact resistance, high heat resistance, flame retardant, reinforced, transparent and other grades.
4. The fluidity is a little worse than HIPS, better than PMMA, PC, etc., and the flexibility is good.

Disadvantages of ABS engineering plastics: low heat distortion temperature, flammable, and poor weather resistance.
Uses: Suitable for making general mechanical parts, wear-reducing and wear-resistant parts, transmission parts and telecommunication parts.

ABS+PC: Commonly known as ABS plus polycarbon. It is one of the few possible permeable materials in China. It cannot spontaneously combust. When burning in an external fire, small particles like polycarbon are precipitated on the surface. The black color is lower than that of ABS.

PBT: Polybutyle terephthalate, English name polybutylece terephthalate (PBT for short), belongs to the polyester series, is composed of 1.4- Milky white translucent to opaque, crystalline thermoplastic polymer made by polycondensation of butylene glycol (1.4-Butylene glycol) and terephthalic acid (PTA) or terephthalic acid ester (DMT) and made by mixing procedure. Ester resin. Together with PET, it is collectively referred to as thermoplastic polyester, or saturated polyester.
PBT can also be called thermoplastic polyester plastic. In order to be suitable for use by different processors, additives are generally added or mixed with other plastics. With different proportions of additives, products of different specifications can be manufactured. Because PBT has heat resistance, weather resistance, chemical resistance, good electrical properties, low water absorption, and good gloss, it is widely used in electronic appliances, auto parts, machinery, household goods, etc. PBT products are also closely related to PPE, PC, POM, PA, etc. are collectively known as the five general-purpose engineering plastics.

POM: Polyoxymethylene is also known as polyoxymethylene, and the English name is polyxymethylene (POM). Milky white opaque crystalline polymer, density 1.42g/cm3, melting point 175°C, decomposition temperature 235~240°C POM plastic is another excellent resin variety developed after nylon, with excellent comprehensive properties.

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