Trends in Mechanical Engineering& Technology Volume 1, Issue 1, February, 2011, Pages 1-21. _____________________________________________________________________________________________ © STM Journals 2011. All Rights Reserved. 1 SIMULATION OF COLD DIE COMPACTION ALUMINA POWDER K. Mohammed Jasim Kadhim 1 *, Adil A. Alwan 2 , Iman J. Abed 3 1 Department of Production Engineering and Metallurgy, University of Technology, Baghdad, Iraq 2 College of Engineering, University of Bayblon, Baibal, Iraq 3 College of Engineering, University of Kufa, Najaf, Iraq *Author for Correspondence email: alimohammed1957@yahoo.com 1. Introduction Powder compaction is a commonly used technique in numerous fields, including the powder technology, geologic, pharmaceutical, and thermal battery industries (Portal, Euvrarde, Tailhades and Rousset, 1993). Uniaxial pressing consists of compacting the pressing powder contained in a rigid cavity, by applying a pressure in a single axial direction with one or more rigid punches. The various pressing techniques differ in the movement of the basic mould elements: top punch, bottom punch and die. In a single action, a uniaxial pressing pressure is applied through the top punch, which enters the cavity holding the pressing powder. After the compacting, the green piece and the top punch withdraw and the movement of the lower punch ejects the piece from the mould (Wagle, Engel, Liu and German, 2000). The compaction mechanism of different material powders is different from each other and the formation ABSTRACT Compaction process was analyzed mathematically by predicting a steady-state mathematical model in order to give more description and understanding for the mechanism of this process. Numerical investigation has been carried out on axisymmetric cylindrical parts using the finite difference method with relaxation technique to examine the physical significance of constitutive model to produce the pressure gradients during compaction. The pressure distribution model is then typically coupled with empirical functions relating pressure and density to obtain a green density distribution at all nodes in the green compacts. The model has addressed the influence of frictional forces acting at the powder and die walls interfaces which dissipate the applied pressure throughout the compact. The effect of the compact geometry has a similar effect on the uniformity of green pressure and density distributions through the compact. It was found that a small aspect ratio resulted in a more uniform distribution than a higher aspect ratio. Therefore, the model seems to work better for the lower aspect ratio. The constitutive model predicts accurately the pressure and density distributions during compaction process. Keywords: Finite difference method; Die compaction; Green density distribution; Aspect ratio; Alumina powder; Relaxation technique