The Effect of Speed on Coefficient of Friction in African Plum Oil (Dacryodes Edulis) Lubricant

One of the major factors influencing the variation of friction between surfaces in contact is the speed; we are faced here with the problem of determining the optimum speed between surfaces in contact in order to improve on the mechanical properties and performance of the entire system. This project investigates experimentally the effect of rotational speed on the (CoF) between aluminum disk test samples in contact with stainless steel pin using plum oil as a lubricant under thin film lubrication conditions. We first extracted plum oil using the manual pressing method and then carried out friction tests on a pin-on-disk tribometer as per ASTM-G 99 standards at room temperature. Rotational speeds between 500rpm and 3000rpm and normal loads of 10N and 20N were deployed as the operating variables and the variation of the (CoF) at predefined rotational speeds and normal loads was studied. Working time for each test was 20 minutes and each test was run twice and average value of friction force calculated. It was observed the CoF decreases with increasing rotational speed from 500rpm-1500rpm speed range and increases with increasing rotational speed from 1500rpm-2500rpm speed range while there is a slight drop from 2500rpm-3000rpm and an optimum speed range attained between 1250rpm-1500rpm where we experienced the least value of coefficient of friction for this specific material combination and test conditions. To further investigate other factors that affect the coefficient of friction and the validity of these results, more studies are needed.