| dc.description.abstract | For the purpose of increasing the machinability of carbon steel, it is crucial to carry
out research in order to obtain the optimum cutting condition. However, it is noted
that today machining process should be done dry due to effort in saving environment
thet while reducing production cost. In dry machining, tool is exposed directly to heat
generated during machining and it is potential to deteriorate the cutting tool and
surface finish. In order to realize the objective of research reported in this thesis, the
cutting tool made of carbide (WC-Co) and carbide which was coated by ceramic based materials (TiC+Al2O3+TiN) under Chemical Vapor Deposition (CVD) method
was selected This cutting tool was used to machine carbon steel AISI-1045 under
wet and dry cutting environment. In the meaning of obtaining the optimum cutting
condition for increasing the machinability of carbon steel, the Response Surface
Methodology (RSM) with Central Composite Design (CCD) at a = 1 was utilized The
preliminary study to determine the cutting parameter as stipulated in JSO-3685
shows that cutting speed (V) of 250 mlmin, feed (I) of 0.1 mm/rev and depth-of-cut (a)
of 1.5 mm is the minimum cutting condition, while the maximum is cutting speed (V)
of 320 m/min, feed (I) of 0.2 mm/rev and depth-of-cut (a) of 2.5 mm. The data
obtained from machining test was analyzed using a shareware Minitab-14 software
and the results were classified into 3 groups and then further analyze with the second
order mathematical equation for resulting the mathematical model of surface
roughness (Ra) and cutting time (tc). From the results, it was determined 4 (four)
points which met the optimum condition, i.e. V 285 m/min, f 0.169 mm/rev, a 2 mm,
Ra 5.22 micron, tc 11.25 minute (resulted under minimum cutting condition) and V
285 mlmin, f 0.185 mm/rev, a 1.939 mm, Ra 6.23 micron, tc JO.OJ minute (resulted
under maximum cutting condition). The optimum cutting conditions resulted under
dry cutting were also tested under wet cutting environment. The results between dry
and wet are Ra (dry) 5. 7166 and Ra (wet) 5. 7417, and tc (dry) 11. 7992 minute and tc
(wet) 12. 9479 minute. Moreover, in term of tool wear, the microanalysis using
scanning electron microscope (SEM) shows the different between wear mode (flank
wear was observed) and surface topography (feed mark) was insignificant under dry
and wet cutting. Statistic test also proves that the different between dry and wet is
insignificant. From this experimental work, it is concluded that RSM method is useful
to obtain the optimum cutting condition as the objective of this study. Moreover, dry
machining is possible to be implemented for increasing the machinability of AISI 1045 by using the CVD-coated carbide. | en_US |
