Research On Process And Control Of Micro-droplet Jetting Technique Based On Converse Piezoelectric Effect

Micro-droplet injection molding (MJM) technology is a more advanced rapid prototyping technology. This technology has the function of molding parts with drop-on-command method, works close to the old-fashioned ink-jet printers. Under the control of the piezoelectric crystals, the MJM device could generat the droplets material and jet to the specified location to form a part, so this technology has the advantage of simple and precision. MJM technology not only has the advantage of low-cost, simple structure, high precision etc, and but also has a good prospect in functionally graded parts, bio-manufacturing and micro-manufacturing field. The project produces a micro-droplet injection rapid prototyping system, including forming head, motion control systems and computer data processing software.The thesis studies the process and control of micro-droplet jetting technique. The thesis also designs a MJM device with corresponding control software and hardware and does experiments of the MJM technology and come to reasonable experimental parameters.Subject produced a MJM system includes computer data processing software, motion control systems, forming head three parts.This thesis designs a control software as the RP pre-treatment process. The software can input the STL format data from Pro/E software, calculate the data of each layer's profile, compensate the profile's data, program the scan route, and make out the RP machine control information.The motion control system use TMS320F2812DSP to receive the control command from the computer and control the servo motor via PID algorithm, linear interpolation algorithm. Then the XY table will move according to the appropriate instructions. Thus the MJM device will be better controlled.When the 3D printer begins to make a solid part, the thermoplastic material is melted and flow into the nozzle. Under the action of the piezoelectric crystal's piezoelectric effect, the nozzle could constant spray out the thermoplastic materials. Under the principle of the siphon, a certain amount of negative pressure could generate in the forming head, so the material in nozzle will not drop out without the effect of piezoelectric. This thesis designs a forming head witch could on-demand spray wax droplets to modeling part both simple and controllable. The subject also made a micro-drop experiment, analysis of various experimental parameters on the performance of spray droplets. This thesis is important on the research of the MJM technology in the future.