Developing PC-Based Servo System of Micro-EDM for Preparing Nanosilver Colloid

As the industrial electrical discharge machine (EDM) has the defects of high cost and large volume in preparing nanosilver colloid, this study designs a micro-electrical discharge machine (micro-EDM) for preparing nanosilver colloid. This micro-EDM comprises mechanical structure, a PC-Based real-time control system, and a servo circuit. As the electrode-holder of mechanical structure is made by 3D printer, manufacturing costs and implement volume are greatly reduced. The PC-Based real-time control system can implement electrode gap control, discharge circuit control, and real-time process monitoring through the servo circuit. The PC-Based real-time control system is implemented by VisSim software and the RT-DAC4/PCI card, thus, the partial electronic circuit of EDM can be replaced by software through this card to reduce the circuit size and cost. The nanosilver colloid prepared by this micro-EDM is analyzed by precision instruments. The results prove that the microEDM can prepare the same nanosilver colloid as that prepared by industrial EDM. The micro-EDM designed in this study has lower cost and smaller volume than traditional EDM, and the discharge condition in the process can be real-time monitored by computer.