NEW DIAMOND GRINDING WHEELS WITH ELECTRICALLY CONDUCTIVE CUTTING EDGES
The application of an electrically conductive diamond material to a new type of grinding wheel whose cutting edges possess electrical conductivity has been tried in this research work. Firstly, electrical discharge machining is applied on a solid surface of an electrically conductive CVD diamond film to create protrusions like cutting edges. Secondly, it is confirmed that the EDMed surface of the diamond material has an ability of stock removing when used in the form of a small lapping wheel. Thirdly, two different types of grinding wheels for micro grinding, i.e. i) a V-shaped profile wheel and ii) a micro mounted wheel, have been manufactured. And it is found that very fine V-shaped grooves can be made on a cemented carbide workpiece by using those wheels with very small wheel wear.
On-Machine Trueing/Dressing of Metal Bond Grinding Wheels by Electro-Discharge Machining
Summary This paper describes a newly proposed method for carrying out effective and precise trueing and dressing of metal bond grinding wheels on an NC grinding machine or a machining center by utilizing wire or die sinking electro-discharge machining(EDM). The main feature of this method is that a staple ED unit is mounted on the NC table of the grinding machine. Thereby trueing for eliminating the eccentricity of wheels and for generating or correcting profiled wheels is carried out by the help of NC movement of the table, keeping the grinding wheel on a machine spindle. In order to prevent the influence of wear of a block electrode in die sinking EDM, another new method is proposed for shaping or correcting the form of the electrode with a cutting tool on the grinding machine by the help of NC movement of the table. The superior effects of the proposed methods have been confirmed in the case of grinding of ceramic material with cast iron fiber bond diamond wheels.
Design and assembly of ternary Pt/Re/SnO2 NPs by controlling the zeta potential of individual Pt, Re, and SnO2 NPs
AbstractIn this study Pt, Re, and SnO2 nanoparticles (NPs) were combined in a controlled manner into binary and ternary combinations for a possible application for ethanol oxidation. For this purpose, zeta potentials as a function of the pH of the individual NPs solutions were measured. In order to successfully combine the NPs into Pt/SnO2 and Re/SnO2 NPs, the solutions were mixed together at a pH guaranteeing opposite zeta potentials of the metal and oxide NPs. The individually synthesized NPs and their binary/ternary combinations were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning transmission electron microscopy (STEM) combined with energy dispersive X-ray spectroscopy (EDS) analysis. FTIR and XPS spectroscopy showed that the individually synthesized Pt and Re NPs are metallic and the Sn component was oxidized to SnO2. STEM showed that all NPs are well crystallized and the sizes of the Pt, Re, and SnO2 NPs were 2.2, 1.0, and 3.4 nm, respectively. Moreover, EDS analysis confirmed the successful formation of binary Pt/SnO2 and Re/SnO2 NP, as well as ternary Pt/Re/SnO2 NP combinations. This study shows that by controlling the zeta potential of individual metal and oxide NPs, it is possible to assemble them into binary and ternary combinations.
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