The evolution of paste pressure during stencil printing

Purpose - The objective of this investigation is the derivation of a mathematical model that describes the pressure characteristics of paste during the stencil printing process. This model is intended to generalise a qualitative understanding of these effects using squeegees that can be curved but otherwise are standard in design. Design/methodology/approach - This is an analytical treatment of the paste behaviour from the foundations of continuity of fluid flow and shear stresses that are imparted by the squeegee blade movement. Findings - An equation is obtained that profiles the pressure generated by the squeegee movement which, for the case of a linear squeegee, shows very good agreement with predicted pressure profiles using experimental data. Practical implications - This model provides a theoretical framework for a better understanding of how to overcome the failure modes inherent in stencil printing, such as over- or under-filled stencil cavities. Originality/value - This is a generalisation of a previously developed mesh printing model. It goes beyond flat squeegee designs to describe the printing process when the blade and stencil are in contact. In addition, it encompasses non-Newtonian fluid behaviour. © Emerald Group Publishing Limited.