NATIONAL TRIBOLOGY CONFERENCE 24-26 September 2003 THE ANNALS OF UNIVERSITY “DUNĂREA DE JOS“ OF GALAŢI FASCICLE VIII, TRIBOLOGY 2003 ISSN 1221-4590 176 TRIBOLOGICAL SOLUTION TO REDUCE THE WEAR RATE IN THE DIE AND THE CYLINDER FOR CERAMIC MUFF A. Tudor 1 , T. Laurian 1 G. Pl ă ia ş u 2 , I. Prava 2 , C. Savu 2 , R. Negriu 3 *) “Politehnica” University of Bucharest; România, 2 “Quartz” Company of Târgovişte, Romania 3 “Senco Plasma Cer” Company of Bucharest, Romania tudor@meca.omtr.pub.ro ABSTRACT A simple physically – based model for the adhesive wear of steel material is presented on the mechanics and mechanisms associated with Bingham flow ceramic mixture. The model is based on the assumption that any contact point between cylinder and ceramic mixture is sliding. This model is used to decrease the wear of mechanical system (cylinder and metallic die) to manufacture a ceramic muff. The solution technique to increase the durability of cylinder and die for ceramic muffs can also be used to solve arbitrary study cases. KEYORDS: adhesive wear, Bingham flow, ceramic mixture, tribological layer, wear model. 1. INTRODUCTION Friction and rubbing of materials are among the most common phenomena in mechanics, present whenever two bodies come into contact. It is well known, however, that phenomena of contact and friction of solid bodies are among the most complex and difficult to model of all mechanical events, primarily due to the complex structure of engineering surfaces, the severe elasto-plastic deformation, damage, heat generation, the presence of contaminants, lubrication and even chemical reactions on these contact surfaces. Fig.1. Picture of ceramic muff. In the manufacturing processes to form the ceramic muff (Fig. 1), the ceramic mixture is pressed in the gap of die and the cylinder (Fig. 2). The flow of ceramic mixture is considered as a Bingham flow. The solid abrasive particles are fine dispersed in plastic paste, but are pressed to the wall of cylinder and die. Fig. 2. Picture of cylinder and die. The durability of the mechanical system to form the ceramic muff is limited by the wear of cylinder and the die. The aims of this paper are the application of the effect of ceramic mixture flow in the gap between cylinder and die and the definition a wear model for the wall. A practical solution is proposed. 2. FLOW MODEL OF CERAMIC MIXTURE The ceramic mixture is considered as a Bingham fluid and can be evaluated by the apparent dynamic viscosity η and the flow limited strength τ o . Figure 3 shows the geometry of gap and the boundary conditions of the ceramic mixture flow.