DRILLING OF AUSTENITIC STAINLESS STEEL AISI 316L USING CARBIDE TOOLS UNDER DIFFERENT COOLANT CONDITION

Ahmad, Zubair Sultan (2016) DRILLING OF AUSTENITIC STAINLESS STEEL AISI 316L USING CARBIDE TOOLS UNDER DIFFERENT COOLANT CONDITION. Doctoral thesis, Universiti Teknologi Malaysia.

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Abstract

The use of excessive cutting fluids in machining has significantly improved the productivity and quality of machined parts. However, its negative effects on the manufacturing cost, health, and environment raise the need for alternative cooling technique. Appropriate coolant conditions during the machining process can lead to reduction of production costs and also minimise environment impact. In this study, an experimental investigation on the effects of machining parameters and cooling strategies on various machinability aspects when drilling austenitic stainless steel AISI 316L using different carbide tools were conducted. Cooling strategies include dry, flood and minimum quantity lubricant (MQL). The machining responses that were addressed include tool life performance, surface integrity and product quality. Besides that, combination of three types of solid tungsten carbide tools, namely uncoated, TiAlN and TiSiN coated, three different cutting speeds (12, 18, 24 m/min) and three feed rates (0.025, 0.040, 0.055 mm/rev) using three different lubricants (mineral oil, refined palm olein (RPO) and jatropha curcas oil (JCO)) were employed in three stages of experiment. At the first stage, combination of lower cutting speed and lower feed rate with uncoated solid carbide twist drills under flood condition provides optimum result in terms of tool wear, surface roughness, circularity, thrust force and torque. These optimal cutting speed and feed rate were then applied in the second and third stages in order to compare the proposed coolant condition (MQL) with existing flood technique. In order to estimate the cutting performance for practical applications in dealing with the corresponding drill, empirical predictive models were developed for tool life, surface roughness, cutting force, circularity error and torque. The models were assessed quantitatively and showed good agreements with the experimental data. It was found that cutting speed and feed rate are inversely proportional to the tool life. Cutting force and torque increased with an increase in feed rate, whilst the values of trust force and torque decreased within a narrow range as the spindle speed increases. In relation to surface roughness, it was found that surface roughness tends to increase when feed rate increases. Results also showed that uncoated carbide tool under flood drilling outperformed TiAlN coated tool under RPO-MQL technique while TiSiN coated tool under JCO-MQL demonstrated better performance than TiAlN. As a conclusion, JCO-MQL using TiSiN carbide tool is feasible to replace flood drilling as the tool wear (13 minutes) and surface roughness (1.77μm) remained close to those obtained under flood drilling (15.50 minutes and 1.41μm respectively) while resulting waste in coolant fluids is very high.

Item Type: Thesis (Doctoral)
Subjects: T Technology > TJ Mechanical engineering and machinery
Divisions: Department of Mechanical Engineering > Teknik Manufaktur
Depositing User: Dr Ahmad Zubair Sultan
Date Deposited: 29 Dec 2016 00:32
Last Modified: 29 Dec 2016 00:32
URI: http://repository.poliupg.ac.id/id/eprint/160

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