Characteristics of silicon rubber keypad screen printing process

With the rapid development of communication and electronic industry, rubber button production has also developed into a mature technology.These key products are formed by silicon rubber through high temperature molding, forming the required key surface, and then through spraying, screen printing, punching and stripping and other processes.This paper discusses the screen printing process of rubber keys.

One, the characteristics of silicone rubber keys

As the key material of silicone rubber, the hardness is generally about 45°, printing single key surface convex, concave and plane, all for line printing.In addition to requiring accurate position and clear text and text, printing ink is also required to be suitable for printing silicone rubber, ink layer reaches a certain thickness, with strong adhesion and wear resistance, high temperature baking does not change color and other characteristics.Therefore, it puts forward special technical requirements for screen printing process.

Second, screen printing technology

Screen printing plate making methods are many, mainly using photosensitive plate making method, that is, the photosensitive adhesive coating directly on the net, after drying, the formation of a certain thickness of photosensitive film as a graphic carrier, the process flow is:

Screen selection → selection frame → stretch the screen → cleaning screen → drying → coating photosensitive adhesive → exposure → development → printing

The specific process is as follows:

1.Net frame

General use of aluminum alloy, easy to operate, strong deformation.Before stretch the net, wipe the net frame with cyclohexanone, remove the residual grease and dirt, and then wipe with industrial alcohol, and finally clean with water, and then dry the net frame.In the operation of screen printing plate, need to be dried many times, so the drying condition and cleaning should be strictly controlled.

2.Stretch mesh

First select screen, rubber use nylon mesh screen printing, printing ink over net rate, constant tension, use can network with box machine side and 6 ~ 10 cm more net frame periphery of wire mesh, using pneumatic stretch mesh machine tension net, and six point method with the tension meter test, after reaching the required tension, coating adhesive to screen glued down in the net frame, with hot air blowing speed up drying, after about 5 minr cements, tightening can turn off the machine, excess screen glued on the outside of net frame, to facilitate the adhesion fastness of keep the screen.Cut off the excess screen, with cyclohexanone, industrial alcohol to clean the screen surface after drying.If tension tension is not stable, it may cause font deviation and blurring, there is a chord substrate caused by the thickness of the ink layer.Plane orthography printing requires large tension screen, the substrate surface with arc surface requires small tension screen, the screen tension range of the process application is 3N/Cm ~ 7N/Cm.General tension screen short service life, the process should be selected according to needs: printing conductive ink with 100 mesh straight screen, printing orthography, color block with 200 ~ 300 mesh oblique screen, to ensure the thickness of ink layer and the integrity of text and text.