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.
XIE Dan1,2,ZHANG HongHai1,2,SHU XiaYun1,2,Xiao JunFeng1,2 & CAO Shu1,2 1Institute of Micro-Systems,School of Mechanical Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074,China
Fluid dispensing is a method by which fluid materials(such as epoxy,adhesive,and encapsulant) are delivered in a controlled manner in electronics packaging.Fluid jetting,derived from inkjet technology,is a noncontact,data-driven fluid dispensing technology.But ideal fluid materials for packaging are usually high viscous,which is difficult to realize by traditional inkjet technology.In this paper,a mechanical micro-droplet jetting system for high viscosity fluid was proposed.It consists of dispensing valve,motion stage,temperature control subsystem,pneumatic subsystem,driving circuit for solenoid valve,and system control software.Performance of this system under various circumstances was studied by changing several parameters,including working temperature,stroke length,back pressure and drive pulse width.Tiny droplets of 0.35 mm in diameter were produced by stainless steel nozzle of 0.2 mm in diameter in the experimental study.
SHU XiaYun1,2,ZHANG HongHai1,2,LIU HuaYong1,2,XIE Dan1,2 & XIAO JunFeng1,2 1 School of Mechanical Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074,China
