| dc.description.abstract | The objectives of research reported in this thesis are to determine the cutting
condition which has a good possibility to realize the green machining ( dry
machining) concept for high grade steel alloy, studying surface topography (surface
roughness, lay, waviness, and defects), surface metallurgy (sub"'surface alteration)
and mathematical model for surface roughness (Ra) which subjected to cutting
condition. There were 9 (nine) samples made of high grade steel alloy AISI 4337
resulted under green machining operation and cutting speed (V) of 200 m/min, 250
m/min, 300 m/min; feeding (f) of 0.15 mm/rev, 0.2 mm/rev, 0.25 mm/rev; and depth
of cut (a) of 1 mm, 1.5 mm, 2 mm. Under those cutting conditions, the variations of
samples were also determined by tool flank wear with VB of0.1 mm, 0.3 mm and 0.6
mm. For the purpose of studying surface topography, the scanning electron
microscope was used while optical microscope and microhardness tester were for
surface metallurgy. Data resulted from the experiment was then compiled and
analyzed by using Taguchi method Lg (34
). The results of machining experiment
show that the average surface roughness (Raavg) obtained at optimum cutting
condition when VB of 0.1 mm, 0.3 mm and 0.6 mm are 1.467 micron, 2.133 micron
and 2.8 micron, respectively. Those results were obtained under green machining
environment and while those were carried out under wet machining, the results
recorded are 1.833 micron, 2.667 micron, and 3.0 micron, respectively. In the case of
surface metallurgy, the average microhardness under green machining in Vickers unit
(HVavg) are recorded 260.0896, 298.0662, and 282.5247 when VB 0.1 tm:n, 0.3 Illlll,
and 0.6 mm, respectively. Under wet machining, the results recorded are 257 .9939,
259.1587, and 260.4706, respectively. By using the multi linear regression, the
mathematical models for surface roughness and sub~surface alteration
(microhardness) can be derived in function of roughness or microhardness and flank
wear. Moreover, it's obtained that the optimum cutting condition is the cutting
condition which resulting surface roughness of 2.8 micron. From the results obtained
in this study, it can be concluded that green machining produces better quality of
machined surface comparing to wet machining and it is also proved statistically by F ~
test. Therefore, green machining is an option with good possibility can be
implemented for manufacturing industry. | en_US |
