Novel electrical discharge machining system with real-time control and monitoring for preparing nanoiron colloid

Kuo-Hsiung Tseng,Mei-Jiun Chen,Yi-Kai Tseng,Chaur-Yang Chang

doi:10.1177/1687814018791705

Abstract

Nanoiron colloid is remarkably suitable for medical, engineering, and other applications because it exhibits excellent properties such as nontoxicity, biocompatibility, and high chemical stability. Because no studies have examined preparation of nanoiron colloid through electric spark discharge method, an electrical discharge machining system for preparing nanoiron colloid was developed in this study based on automated electric spark discharge method with real-time monitoring. An Arduino microcontroller, laser positioning technology, and closed-loop motor control were combined for automatic alignment of the two discharge electrodes. This electrode alignment method enabled achieving electrode alignment accuracy of 0.139 mm. The real-time monitoring applied the Ziegler–Nichols method with a proportional–integral–derivative controller for closed-loop control of the interelectrode gap that, compared with the manually tuned proportional–integral–derivative controller, increased the interelectrode gap discharge success rate from 22.25 to 28.99. A user-friendly interface and process parameters were realized through VisSim software, an Arduino microcontroller, and an RT/DAC4 PCI card. This design enabled obtaining data on process efficiency and providing real-time process diagnosis. Compared with colloids prepared using chemical methods, the nanoiron colloids prepared in this study contained only iron and oxygen; therefore, they would be safer for application in the human body. According to the UV-Vis and Zetasizer analyses, the absorbance peak of the nanoiron colloid prepared with this system ranged from 200 to 220 nm, and the zeta potential was approximately –11.6 mV with a diameter of approximately 155.9 nm. These results verified that this electrical discharge machining system can prepare nanoiron colloid featuring excellent suspension stability.

Highlights

Nanotechnology has made prominent progress in recent years along with the rapid progress of science and technology, and nanomaterials are widely used in engineering, agriculture, and biomedicine and other fields.[1]
The application of electric spark discharge method (ESDM) for the preparation of nanoparticles belongs to the physical method, which first uses the high temperature generated from an electric spark to evaporate the surface of the metal materials and to condense the metal vapor, as generated at the evaporation moment, into tiny particles with the use of dielectric fluid
Many literatures have used this method to prepare nanometal colloid;[10,11,12,13] the device used in such research is an expensive industrial-grade electrical discharge machining (EDM), costing at least US$34,000; how to improve the design of the EDM to reduce the cost of the machine and tools has become a subject that uses ESDM to prepare nanometals

Summary

Introduction

Nanotechnology has made prominent progress in recent years along with the rapid progress of science and technology, and nanomaterials are widely used in engineering, agriculture, and biomedicine and other fields.[1]. Many literatures have used this method to prepare nanometal colloid;[10,11,12,13] the device used in such research is an expensive industrial-grade electrical discharge machining (EDM), costing at least US$34,000; how to improve the design of the EDM to reduce the cost of the machine and tools has become a subject that uses ESDM to prepare nanometals. These studies have mainly used visual inspection and manual adjustment to align electrodes. Because ESDM process efficiency is proportional to the electrode discharge success rate (DSR), monitoring this rate will be beneficial to the improvement of process efficiency

Methods

Results

Conclusion