Multi-materials drop-on-demand inkjet technology based on pneumatic diaphragm actuator

Micro-droplet jetting belongs to the field of precision fluid dispensing techniques. Unlike traditional subtraction manufacture process, micro-droplet jetting as an additive fabrication technique with features of non-contact and data-driven represents a new development trend of modern manufacturing process. In this paper, the design, fabrication and performance of a multi-materials drop-on-demand (DOD) inkjet system based on pneumatic diaphragm actuator were described. For capturing the droplet ejection process and measuring the droplet dimension, a self-made in situ imaging system based on time delayed external trigger was set up. The performance of the generator was studied by adjusting the structure and control parameters. Furthermore, the influence of fluid properties on the droplet ejection process was experimentally investigated. Micro-solderballs of 160.5 μm in diameter and UV curing adhesive micro-bumps of 346.94 μm in contact diameter with the substrate were produced. The results demonstrated that the DOD inkjet generator possesses characteristics of robust, easy to operate and maintain, and able to withstand high temperature as well as applicability to a wide variety of materials including polymers, low melting point resin and high melting point metal. The system has a great potential of being used in the fields of IC and MEMS packaging, 3D printing, organic semiconductor fabrication, and biological and chemical analysis.