Equipment For Magneto-abrasive Finishing Of Roller Bearing Balls

6th International DAAAM Baltic Conference INDUSTRIAL ENGINEERING 24-26 April 2008, Tallinn, Estonia EQUIPMENT FOR MAGNETO-ABRASIVE FINISHING OF ROLLER BEARING BALLS Deaconescu, T. & Deaconescu, A. Abstract. The processing of surfaces by magneto-abrasive erosion is achieved by working media with both magnetic and abrasive properties, the binder of the grains forming the working medium being the magnetic field. The paper presents a device for magneto-abrasive finishing of roller bearing balls adaptable on a universal milling machine. Keywords: magneto-abrasive finishing, roller bearing balls. 1. INTRODUCTION Abrasive erosion holds an important weight amongst surface machining processes, this being a technological method of dimensional machining by means of cutting – scratching – plastic deformation of the part surface carried out by the abrasive grains held in a solid, liquid, gas or magnetic support. This procedure is based on the destruction of the integrity and subsequent removal of the tooling allowance at the surface of a part, by means of the dynamic action of the erosive agents, materialized by solid particles (abrasive grains). The use of abrasive grains as cutting tools aims mainly at rendering special quality surfaces of high precision in regard of dimensions, form and position. Achieving these objectives however requires small values of the tooling allowance, often even under one micron [1]. Considering these requirements, Japanese researcher Norio Taniguchi has introduced the concept of „nanotechnology”, placing abrasive erosion within this category of cutting procedures [2]. Abrasive erosion can be achieved with the grains fixed in a solid body (procedures known as grinding, honing, etc.), with semi-free grains held by a magnetic field or a viscous liquid medium (known as magneto-abrasive finishing, lapping, ultrasound dimensional machining, etc.), or with free grains set into motion by a small viscosity liquid or gas (abrasive jet cutting). Magneto-abrasive finishing falls into the category of machining by abrasive erosion, the principles of which are presented in the following. 2. MAGNETO-ABRASIVE FINISHING The first mention of a magneto-abrasive machining procedure is connected to the name of the Russian scientist Karol, who in 1938 proposed the use of an alternating magnetic field for finishing the interior surfaces of pipes, by means of magnetoabrasive powders. Further major contributions acknowledged in literature are inter alia those of M. Baron, E.G. Konovalov, L.M. Kozuro in Russia, Al. Makedonski in Bulgaria, and K. Kato, Nakagawa, Taakeo Shinmura, Koya Takazawa, Eiji Hatano in Japan [3]. Machining with magneto-abrasive grains is based on the effects generated by the relative motion and the pressure generated between the part surfaces to be machined and the abrasive particles acting as tools and sustained in the machined area by means of a magnetic field. Magneto-abrasive machining implies firstly the contact between the part surface and an abrasive grain. Maintaining the contact with the machined surface, even for a mobile grain and/or part requires the existence of a sufficiently strong magnetic field on one hand, and ferromagnetic propert