ASSESSMENT OF OIL EXTRACTS FROM TIGER NUT(Cyperus esculentus), WATER MELON (Citrullus vulgaris) andNEEM SEEDS (Azadirachta indica) AS CUTTING FLUIDS IN DRILLING OPERATION OF MILD STEEL
In this study, three vegetable cutting fluid namely: Tiger nut, water melon seed and neem seed were selected in drilling operation of mild steel using High Speed Steel (HSS) cutting tool at varying spindle speeds, feed rate and constant depth of cut. A commercially available convectional mineral oil was used as standard for comparative analysis. Flood method of cutting fluid application was adopted at the cutting zone for the cutting fluids, dry drilling environment was equally subjected to the same cutting parameters as the cutting fluids. The viability of these selected oil as cutting fluids were examined based on reduction in temperature generation, surface finish value and characteristics of chips produced. The results indicated that performance of selectedoil as cutting fluid in term of surface quality was best with water melon seed having 1.6µm surface roughness while conventional mineral oil was having 2.2µm at the same feed rate of 0.05 mm/rev, dry drilling condition was having 4.2µm as the highest value at this stated feed rate. The chips produced shows that all the cutting fluids were having segmented chip which is a good morphology at lower spindle speed but dry drilling environment was having 75% of its chip continuous, with substantial portion being burnt. Reduction in the generated temperature as the spindle speed increased was best achieved with water melon seed oil followed by mineral oil, tiger nut oil and neem seed oil respectively. The performance of selected plant cutting fluid are very similar because of their close physio-chemical properties.
1.1 Background to the Research
Machining is the manufacturing process by which parts can be produced to the desired dimensions and surface finish from a blank by gradual removal of excess material in the form of chips by the help of sharp cutting tools. Engineering components are however subjected to one form of machining or another during manufacturing, thus the application of a cutting fluid is very essential. Cutting fluid also known as metal working fluid, coolants, cutting oils, machining fluids or lubricants, are fluids used in manufacturing industries as coolants and lubricants, designed specifically for metal working and machining processes. Cutting fluids are used to reduce the negative effects of heat and friction on both tool and workpiece.
Historically, the use of cutting fluids in metal cutting was first reported by F. Taylor in 1894. He observed that cutting speed could be increased up to 33% without reducing tool life by applying large amounts of water in the cutting zone (Avila and Abrao, 2001). The cutting fluids produce three positive effects in the process of machining, heatevacuation, lubrication on the chip–tool interface and chip removal (Lopez et al., 2006).Cutting fluids are extensively used in drilling operations for removal of chips from the holes, thereby preventing drill breakages(Braga, et al., 2002). Higher surface finish, quality and better dimensional accuracy are also obtained from cutting fluids (Sokovic and Mijanovic, 2001).
The application of cutting fluidsin machining processes decreasesthe temperature during machining by spraying the coolant on the machining zone. However, growing environmental concerns such as renewability, biodegrability, safety and health of operators demand serious attention(Abdalla and Patel, 2006).