The evolution of paste pressure during stencil printing

Abstract

PurposeThe 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/approachThis 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.FindingsAn 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 implicationsThis 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/valueThis 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.