Surface Quality of Textured Surface on Cylindrical Inner Surface Using Whirling Electrical Discharge Texturing

Abstract

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.

Friction Characteristics with Pin-on-Disc Friction Test on Microstructured Surface Using Whirling Electrical Discharge Texturing

“…In WEDT, the interval between craters and the texture-area ratio can be controlled by changing the pulse frequency and feed speed, respectively. In addition, the crater diameter depends on the discharge current and pulse duration [2,4,5,9]. Figure 2 shows photographs of WEDT equipment.…”

“…It is considered that friction reduction is necessary to improve fuel consumption and reduce environmental impact [1,2]. Surface texturing by creating microstructures on a surface is an attractive method of decreasing the friction coefficient and maintaining a good lubrication condition for sliding parts in vehicles [1][2][3][4][5][6][7][8][9][10]. It is expected that microstructured surfaces can not only act as reservoirs to engender persistent lubrication by increasing the quantity of lubricant during sliding but also act as trapping sites of wear debris and increase the fluid dynamic effect [1][2][3][6][7][8][9][10].…”

“…Therefore, the authors developed whirling electrical discharge texturing (WEDT) as a method for creating microstructures by single-pulse discharge on the inner surface of a cylinder [2,4]. The surface characteristics of a textured surface, such as the texture-area ratio, the total removal volume of craters, crater diameter and crater depth, can be controlled by adjusting the electrical conditions in WEDT [2,4,5,9]. The purpose of this study is to investigate the effect of the lubrication region, the actual contact surface area and the surface characteristics of the textured surface on friction characteristics through pin-on-disc friction tests.…”