PCB ink quality is excellent, in principle can not be separated from the combination of the above several components. Ink quality is excellent, is the formula of scientific nature, advanced and environmental protection of the comprehensive embodiment. It is embodied in:

viscosity

It's short for dynamicviscosity. The viscosity is typically expressed as the shear stress of the fluid flow divided by the velocity gradient in the direction of the flow layer, in Si pas/SEC (Pa). S) or millipas/second (mPa). S). In PCB production refers to the fluidity of ink driven by external forces.

Conversion relation of viscosity unit:

1 of pa. S = 10 p = 1000 mpa. S=1000CP=10dpa.s

plasticity

Refers to the ink by external force deformation, still maintain its deformation before the nature. The plasticity of ink is conducive to improving printing accuracy;

Thixotropic

Ink in the static gelatinous, and touched when the viscosity of a change in the property, also known as shaking, flow resistance;

liquidity

(leveling) the extent to which ink is spread out under the action of external forces. Fluidity is the reciprocal of viscosity, fluidity and ink plasticity and thixotropy. Large plasticity and thixotropy, large fluidity; The imprinting is easy to expand with high fluidity. Small fluidity, easy to appear net, ink phenomenon, also known as reticulation;

viscoelastic

Refers to the ink in the scraper after scraping, the ink was cut and broken quickly rebound performance. Printing ink deformation speed, ink rebound quickly to facilitate printing;

dry

Ink on the screen drying the slower the better, and hope to transfer to the substrate, the faster the better;

fineness

The size of pigment and solid particles, PCB ink is generally less than 10μm, the size of fineness should be less than one-third of the opening of the mesh;

Drawing sex

Ink spatula to pick up ink, silk ink stretching not broken degree known as drawing. Long ink, ink surface and printing surface appear a lot of filaments, so that the substrate and plate dirty, even can not print;

Transparency and hiding power of ink

For PCB ink, according to the use and requirements of different ink transparency and hiding power also put forward various requirements. In general, line ink, conductive ink and character ink, are required to have a high hiding power. And flux resistance is more flexible.

Chemical resistance of ink

PCB ink according to the use of different purposes, the corresponding requirements of acid, alkali, salt and solvent requirements have strict standards;

Physical resistance of ink

PCB ink must be resistant to external scratches, heat shock, mechanical peeling, and meet various stringent electrical performance requirements;

The use of ink safety and environmental protection

PCB ink requires low toxicity, odorless, safety and environmental protection.

Above we summarized the basic performance of twelve PCB inks, and in the actual operation process of screen printing, and the operator is closely related to the viscosity problem. Viscosity of the level of silk screen, whether or not, a great relationship. So in PCB ink technical documents and QC reports, viscosity is clearly marked, indicating under what conditions, with what type of viscosity testing instruments. In the actual printing process, if the ink viscosity is high, it will cause difficulty in missing printing, and the edge of the graph is serrated seriously. In order to improve the printing effect, thinner will be added to make the viscosity meet the requirements. However, it is not difficult to find that in many cases, no matter what viscosity you use in order to achieve the desired resolution (image resolution), it will never be achieved. Why is that? After in-depth study, it was found that ink viscosity is an important factor, but not the only. There is another rather important factor, thixotropy. It is also affecting the printing accuracy.