Performance characterization of drop-on-demand micro-dispensing system with multi-printheads

Due to the diversity of printhead activation mechanism, printhead design and its operational parameters, integrating heterogeneous printheads is usually preferred in multi-material micro-fabrication tasks. However, evaluating the performance of multi-printhead micro-dispensing system is seldom investigated. In this paper, the developed micro-dispensing system performance along X and Y axes is discussed based on the attached two printheads, i.e. solenoid actuating micro-valve and piezoelectric printhead. Comprehensive experiments are conducted to characterize droplet size and their deposition performance on the substrate. To explore the optimal printing parameters (e.g. pitch and printing speed), the characterization results are analyzed in terms of deposition accuracy and line straightness, printable conditions, and stability. It can be concluded that an optimal pitch is the key to achieve better line straightness for micro-valve printhead. For normal printing using piezoelectric printhead, the selection of printing speed is determined in terms of pitch. A lower speed is recommended for both to minimize the disturbance from printheads' point-to-point motion. In addition, some other factors' influence on printing accuracy such as vibrations, printhead synchronization, printing time are discussed. Our study on the relationship between printing parameters and dispensing performance will not only benefit the optimization of micro-dispensing performance, but also the development of theoretical models or empirical equations in the 3D micro-fabrication process.