Papers by Keyword: Compound Process

Abstract: This study presents a compound process combining composite electroforming with wire Electrical Discharge Machining (w-EDM) for developing a thin cubic boron nitride (CBN) grinding-tool. A precisely designed set-up in which a small compound depositing tank providing effectual convection of a compound electroplating solution to help fabricate a CBN grinding-blank is presented. A funneled entrance design for converging CBN grits in the working tank and creating a depositing effect on the substrate is employed and proposed. Considerable micro CBN abrasives are evenly embedded into the nickel-based coating layer, which offers enough abrasives for grinding-edge. Subsequently, the coated grinding-blank is trued and dressed by using w-EDM to form a multiple thin CBN grinding-tool. Experimental results indicate that the electroforming process can create a Ni-based CBN layer of high-integrity under current density of 2 ASD and concentration of 8.6 g/l CBN grits. Moreover, the CBN grinding-edge of 10 μm in thickness (each edge) can be achieved.

Abstract: The semi-solid A356 alloy slurry is prepared by compound process, and the effect of the compound process on morphology and size of primary α-Al in A356 alloy is researched. The results indicate that the compound process remarkably affects the morphology and the size of primary α-Al. Primary α-Al with particle-like is distributed uniformly in A356 alloy, and there is no the transient area of change in structure morphology. Compared with the samples prepared by low superheat pouring and slightly electromagnetic stirring, the nucleation rate, morphology and grain size of primary α-Al in A356 alloy are markedly improved by the compound process. The mechanism of refining grain in the compound process is probed.

Abstract: This study using ultrasonic energy transmitted into the electrolyte to assist in discharging of electrolytic product out of the machining gap in the compound finishing processes of electrochemical finishing and burnishing on hole-wall surface beyond traditional process of holes machining instead of conventional hand or machine polishing. The design finish-tool includes a burnishing-tool and an electrode as a hole-wall surface finish improvement that goes beyond traditional rough boring. In the experiment, the finish-tool travels across the hole-wall surface with continuous or pulsed direct current. The experimental results show that the large supply of current rating is effectively to reach the amount of the material removal and is advantageous to the finishing processes. The average effect of the ultrasonic is more better than the pulsed current while the machining time needs not to be prolonged by the off-time. The finish effect is better with a high rotational speed of the finish-tool because the dregs discharge of electrochemical finishing becomes easier and is also advantageous to the finish. The compound processes of burnishing and ultrasonic electrochemical finishing just require a short time to make the hole-wall surface smooth and bright.

Abstract: A new finish method uses an effective electrode connecting with a nonconductive grinding tool to execute the design of compound processes of electrochemical finishing and grinding following turning is investigated. The submitted processes can be used for various turning operations. Through simple equipment attachment, electrochemical finishing and grinding can follow to execute the finishing process on the same machine. Among the factors affecting electrochemical finishing the performance of grinding combined with electrochemical finishing is primarily discussed. In the experiment, the electrode is used with continuous and pulsed direct current. The grinding tool moves following the electrode and grinds the workpiece surface. The experimental parameters are electrical current rating, feed rate of electrode and grinding tool, rotational speed of workpiecel, pulsed period, and geometry of finish-tool. The results show that pulsed direct current with longer off-time can slightly improve the finish effect for its dregs discharge mobility. Using an adequate rotational speed of workpiece with high rotational speed is advantageous to the finish effect. A thinner plate-form electrode with a smaller end radius is associated with larger discharge space and produces higher current density and provides faster feed rate and a better finish effect. The grinding can effectively increase the finish effect. An effective and a low-cost finish process through the design electrode and using the grinding assistance in the electrochemical finishing after turning process make the surface of workpiece smooth and bright.