PCB ink quality is excellent, in principle, from the combination of the above may be several components. Excellent ink quality, is a comprehensive reflection of scientific, advanced and environmentally friendly formulations. Which is reflected in:
Viscosity is the dynamic viscosity (dynamicviscosity) for short. Said viscosity is generally used, i.e. the shear stress divided by the fluid flow direction, the flow velocity gradient layer, international units Pa / s (Pa.S) or mPa / s (mPa.S). PCB production means in the ink generated by the external force mobility.
Viscosity conversion between units:
1Pa.S = 10P = 1000mPa.S = 1000CP = 10dpa.s
Plasticity refers to the ink deformed by the external force, remains the nature of the deformation front. Help to improve the plasticity of ink printing precision;
Thixotropic (thixotropic) standing gel ink, while the viscosity occurs when a property changes being touched, also known as thixotropy, sag resistance;
Mobility (leveling) ink external force, expanded to the surrounding degree. Fluidity is the reciprocal of viscosity, fluidity and thixotropy of the ink on plastic. Plastic and thixotropic big, big mobility; mobility of the imprinted easily expanded. Mobility of small, prone webs, resulting knot Mexican phenomenon, also known as textured;
Viscoelastic refers ink squeegee blade after being shear fracture ink quickly rebound performance. Requirements deformation speed ink, ink rebound quickly and be conducive to printing;
After drying the ink to dry on the requirements of the network version of the slower the better, but I hope the ink is transferred to the substrate, it is required sooner the better;
The fineness of the pigment particles and the size of the solid material, PCB ink is generally less than 10μm, the size should be less than the fineness of the mesh of the third opening;
Ink drawing of the shovel when provoked ink, ink drawing filamentous degree is not broken is called brushed sex. Ink silk long filaments in a lot of ink and the printing surface face, so stick substrates and dirty plates, not even printing;
Transparency and opacity inks
For PCB ink, depending on the purpose and requirements of transparency and opacity inks also made various demands. Generally, the line ink, conductive inks and ink characters, are required to have a high hiding power. The solder resist is more flexible.
The chemical resistance of the ink
PCB ink according to the purpose of the different requirements of the corresponding acids, bases, salts and solvents and other requirements are stringent standards;
The physical properties of the ink-resistant
PCB ink must comply with external scratch resistant, thermal shock, mechanical stripping, and achieve a variety of stringent electrical performance requirements;
Safe and environmentally friendly ink
PCB ink requirements have low toxicity, odorless, safe and environmentally friendly.
We summarize the basic properties of these twelve PCB ink, which in the actual operation of the screen printing process, the operator is closely related to viscosity problems. Low viscosity for screen printing smoothly or not, the relationship is great. Therefore, technical papers and inks PCB QC report, the viscosity too clearly marked to indicate under what conditions, what type of viscosity measurement instruments.
In the actual printing process, if the ink viscosity is high, difficulties in printing will cause leakage, graphics edge serrated serious, in order to improve the printing results, the diluent is added, the viscosity to meet the requirements. But difficult to find, in many cases, in order to want to get the desired resolution (resolving power), no matter what you use viscosity, are never able to achieve. Why? After in-depth study of classics, only to find that the ink viscosity is an important factor, but not the only one. Another quite important factor - thixotropic. Is it also affects the printing accuracy.
