There are commonly the following fabrication methods of letters on press key surface:

1. Silk-printing：It includes surface printing and bottom printing. During surface printing, press key surface is painted at first, then paint letters and symbols by silk printing, the apply protection oil. Bottom printing is normally used for transparent press keys, it includes two types: silk printing of contour font to cover base color, silk printing of solid font to cover base color. For press keys with large curved surface, transfer printing method can be used: Fonts are etched on steel plate, then transfer the printing ink using rubber head on to press key surface. Transfer printing is mostly adopted in toy industry.
2. When the characters require euphotic effect, normally spray painting and radium engraving methods are adopted: After the press keys are mould, spray printing ink on press key surface, then engrave euphotic characters using laser engraving, finally apply a layer of protection oil. For red shown symbols, firstly transfer print red color on total press key surface, then remove printing ink on the surface after painting to show red color. For other colors, adopt the same process.
3. Press keys requiring electroplating effect can use water electroplating and vacuum electroplating. Many direction press keys nowadays requiring male- and female-mark effect usually adopt electroformed mould, thus made product has clear boundary, and elegant appearance with an effect that can not be reached by vein-exposure directly on the mould. Double shot moulding is normally used for press keys requiring euphotic effect or electroplated press keys. PC material can not be painted by electroplating, while abs material can. The requirement of double shot moulding is to mould PC and abs material together, after electroplating, abs part shows electroplating effect, PC part shows euphotic effect. Currently vacuum electroplating can also make euphotic letters, but vacuum electroplating can not produce a good effect as that of electroplating.
Mobile phone press key surface laser engraving is a kind of treatment of character processing on press key surface painting: The characters’ diameter is normally within 0.04-0.06, then we fill in these characters using lines with 0.04-0.06 spacing. This way we define a patch for laser, then laser will trace this path to engrave off the paint.
To conduct good laser engraving, rapid speed is very important. Only filling method is not enough. Another method likes CNC, path for laser is given. This way we can get clear boundary. Because laser carries high energy during initiation which will result in breakthrough and zigzag boundary.