Development of a drop-on-demand system for multiple material dispensing

In drop-on-demand (DoD) printing, each type of actuation mechanism for the dispensing nozzle has its own uniqueness and limitation in dispensing material properties. To meet the growing requirement of complex parts in industry with multiple properties of materials, this paper proposes a multi-nozzle drop-on-demand (DoD) inkjet printing machine that can dispense multiple material using different type of nozzles. Starting from single nozzle dispensing, a DoD machine generally consists of motion stage, dispensing unit, and visualization system. In multi-nozzle DoD machine, real-time synchronization among the multiple dispensing units is also one of the crucial factors for successful printing with a multi-nozzle machine. A microcontroller-based synchronizer has been designed to synchronize the printing process from multi-nozzle with respect to a movable position stage. This real-time control contributes to accurate micro-droplet deposition. In addition, some measures have also been proposed to improve the machine compactness and save the expense cost, such as the multiplexer, mechanical mounting and so on. Integrated with these techniques into the DoD machine, the developed multi-nozzle system can achieve accurate deposition with a wide range of functional materials using various types of dispensing print heads.