Influence of the Paste Composition On the Rheological Properties of the Ceramic Screen-printing Inks
Paste technology is an economically beneficial manufacturing method, which maximizes the product output and minimizes waste and emissions. It can be used for different applications. Paste technologies are often employed together with the printing and coating technologies.
One of such method is screen- printing, which is considered as one of the most convenient and simplest printing techniques. In the screen-printing process, the paste is transferred on the substrate through the stencil, which is a water and solvent resistant coated screen. Screen- printing is an old, but until now very widely used printing technique due to its practicality. There are several benefits in this printing process such as flexibility of the process and possibility to use huge variety of substrates, inks and pastes. The screen- printing method is often employed for printing parts of energy source devices.
The material of the screen mesh (e.g., PET or metal threads), mesh count (the measure of number of threads per square inch), mesh opening (the distance between two adjacent warps) and mesh thickness determine the percentage of open area and total ink volume to be transferred through the meshes on the substrate. Hence, the screen mesh characteristics regulate the thickness of the printed layer and the minimum possible thickness of the printed line. The higher the mesh count, the finer the lines, that can be achieved.
Consequently, the printing quality depends on the screen type, printer settings, materials, and ink rheology. Most of those parameters can be adjusted and controlled during the process of printing except the ink rheology . Therefore, to optimize the screen-printing process, the rheological parameters of the printing inks must be analyzed and regulated before the printing process starts. Several factors influence the rheological parameters of the pastes such as type of the composites and their chemical and mechanical properties, composition of the pastes, meaning the amount of each variable in a system, and the temperature. In this work, the influence of the paste composition on rheological properties is evaluated. The data analysis is done by a design of experiment program (DoE), called Cornerstone. The correlation between the factors such as binder, solid and powder content on rheology factors is evaluated. The analyzed rheology factors in this case are shear viscosity, complex viscosity and loss factor.