الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Stainless steels have the characteristics of high strength, low thermal conductivity, high toughness and high work hardening coefficient which cause great difficulty in drilling processes.They are used to fabricate chemical and food processing equipment, as well as machinery parts requiring high corrosion resistance. They are generally regarded as more difficult–to-machine than carbon and low alloy steels on the account of their high strength, high work hardening tendency and poor thermal conductivity.This research aims to identify and discuss the machinability of different types of stainless steel materials during drilling operation using different methods of interpretations including, rapid drilling tests, cutting force, specific cutting energy, and tool wear. In order to achieve these aims, groups of experiments have to be conducted. The experimental work is divided into four sections; main drilling tests, rapid drilling tests, chip formation analysis and tool life analysis.The experiments are performed using different types of stainless steels which are the freemachining AISI-303 stainless steel and the nonfree-machining AISI-304, AISI-316 and UNSS32205 stainless steels. HSS-TiN M35, HSS-TiAlN/TiN M35, HSS-M4 and carbide-ISO M30 cutting tools are used to drill the work materials. A Kistler dynamometer 9271A with data acquisition system is used for measurement of the feed forces and torques. The signals of feed force and torque from the dynamometer are transmitted to a Kistler 5017B type multi- channel 8-channel) amplifier, and then recorded on a computer using „LABVIEW software.
A morphologic analysis of chips is carried out at different cutting speeds and constant feed (0.12
mm/rev) to study the influence of the cutting speed on the chip thickness. The chip thickness is measured using a Scanning Electron Microscope (SEM). Also, chip hardness is measured different cutting speeds and constant feed (0.32 mm/rev) using Rebound Hardness Tester, to verify the machinability of the four investigated stainless steels and to study the effect of cutting speed on chip hardness. Monitoring of drill bit wear is an important issue, since it affects the life of the drill bit. The flank wear is measured using universal measuring machine and flank wear VB=0.2 mm is considered for tool life measurements.The application of Taguchi technique and analysis of variance (ANOVA) for minimization of feed force, cutting force, torque and specific cutting energy influenced by drilling cutting parameters has been presented. The optimum drilling parameter combination is obtained by using the analysis of signal-to-noise ratio. It has been confirmed that feed rate is the most influential factor on the feed force and specific cutting energy, while cutting speed significantly affects the cutting force and torque. The correlations between the drilling parameters and feed force, cutting force, torque and specific cutting energy are determined using multiple linear regressions.