Abstract. The authors developed Whirling Electrical Discharge Texturing (WEDT) in order to reduce friction coefficient of cylinder-shaped parts. In previous research, the authors verified fundamental characteristics of WEDT by observation of textured surface. It was found that a crater shape and texture-area ratio can be controlled by WEDT. The texture-area ratio depends on feed speed of tool electrode. In this research, crater depth, crater diameter, texture area ratio and total removal volume of craters were investigated to confirm characteristics of WEDT in detail. In addition, tungsten wire was used as a whirling shaft in order to improve stability of whirling phenomenon. Moreover, a textured surface was finished by lapping-film in order to remove protrusions around craters and reduce friction coefficient. As a result, it was verified that the texture-area ratio slightly increased with decreasing feed speed and it was confirmed that crater depth, crater diameter, and total removal volume of craters were also related to feed speed.
Discharge duration and pulse frequency are studied to determine the optimum conditions for creating a single crater. In addition, the relationships between pulse frequency and surface characteristics using Whirling Electrical Discharge Texturing (WEDT) are determined. It is confirmed that the texture-area ratio and the total removal volume of craters, but not crater diameter or crater depth, can be controlled by adjusting pulse frequency. Moreover, after honing, surface characteristics decrease owing to the removal of protrusions. With honing, the surface roughness of the textured surface leads to a reduced friction coefficient as expected.
Whirling Electrical Discharge Texturing (WEDT) was developed to create microstructures. It was thought that textured surface with low surface roughness could reduce friction coefficient on the sliding parts. In this research, surface quality was studied to evaluate the quality of WEDT textured surface. Surface quality was evaluated in terms of the surface roughness and surface integrity which were characterized by microstructure, composition and residual stress of the textured surface. The value of Rp and Rv of textured surface after finishing with improved finishing method were obtained as expected for low surface roughness to reduce friction coefficient. In addition, it was clarified that microstructure and composition of textured surface after texturing with WEDT and finishing with lapping-film depend on feed speed. Furthermore, the compressive residual stress was presented on WEDT textured surface and depended on feed speed. It was confirmed that good surface quality of textured surface could be obtained by WEDT.
This paper describes a highly efficient deburring technology that employs Whirling Electrical Discharge Machining (Whirling EDM). Whirling EDM was developed because burrs on the backside of smalldiameter holes, such as cross-drilled holes are not easy to remove. Many short circuits occur, due to the design of the compliant tool and the tool’s uncontrollable deflection. Therefore, a feedback circuit was developed in order to increase the probability of normal discharge. In conclusion, normal discharge increased due to the feedback circuit, and Whirling EDM can successfully deburr the backside of small-diameter holes in a highly efficient manner.
This paper describes a high efficient deburring method by using Whirling Electrical Discharge Machining (Whirling EDM). Since, a backside deburring of small-diameter like cross-drilled hole is not easy to machine so Whirling EDM was developed. There were many short circuits which causes by uncontrolled deflection of tool electrode therefore the feedback control system was developed in order to increase the probability of normal discharge. In conclusion, the normal discharge had increased due to the feedback control system, high efficient deburring process of backside of small-diameter hole can be successfully carried out with high efficiency by using whirling EDM.
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