The effects of lubricants on temperature distribution of 6063 aluminium alloy during backward cup extrusion process

Abstract

Backward extrusion has received several applications in the production and manufacturing sectors, most importantly in the bulk forming processes and various researchers have carried out several studies about backward extrusion processes in the time past varying from experimental, theoretical, empirical, analytical to numerical methods in order to analyze and optimize it. In this present investigation, backward cup extrusion of AA6063 was successfully carried out experimentally and theoretically using tropical coconut oil and castor oil as lubricants. The experiment was also carried out without lubrication. With the different lubricating conditions, the strain rate was varied at 1.5 × 10−3 s−1, 2.0 × 10−3 s−1, 2.5 × 10−3 s−1 and 3.0 × 10−3 s−1 respectively. A numerical analysis using DEFORM 3D software for backward cup extrusion at strain rates of 2.0 × 10−3 s−1 and 2.5 × 10−3 s−1 were then performed to determine optimum lubricated condition and temperature distribution during the deformation. It was found that the temperature increased with increasing strain rates. At a higher strain rate, the temperature of both punch and lower die also increased. The highest temperature was observed when lubricated with tropical coconut oil at a strain rate of 3.0 × 10−3 s−1 which was observed to be above 33 °C when compared to other lubricants. The punch temperature showed a higher temperature compared to the lower die temperature in all cases. The extrusion load–stroke curve of the simulation result was consistent with the experimental results. Keywords: Backward cup extrusion, Lubricants, Strain rate, DEFORM 3D, Temperature distribution