Positional accuracy for ink jet deposition in digital fabrication

Abstract

Components or systems that rely on ink jet deposition of complex materials for functional reliability may require a very high level of drop placement accuracy. Drop placement accuracy is a function of print head jetting properties and the mechanism controlling the print head position relative to the substrate in both a spatial and temporal sense. This paper will focus on the control and minimization of positional errors to afford the best opportunity for minimal drop placement error from a given print head. Ink jet deposition is a static and dynamic process that depends on mechanical tolerances, changes in position during motion, and predicting position prior to the actual event of drop ejection. Traditional methods for error assessment use positional accuracy and repeatability as the primary measure. The emphasis for this paper will be on the motion control and mechanical error sources that affect these parameters. Methods for measuring and techniques for reducing error along with examples will be presented.