When the variance analysis results of flank wear values is studied, it is seen that
the changes in tool type, cutting speed and depth of cut have a significant effect on
flank wear an that the effect of progress at 95% confidence level is insignificant. It
was observed that tool type is the most effective parameter with F=10.04.
When the experimental findings are studied in general, the smallest ideal Ra value
was found with CBN cutting insert at the cutting conditions of Vc= 225 m/min., f=
0.05 mm/rev. and ap=0.2 mm; the most ideal result at cutting conditions of Vc=
300 m/min, f= 0.05 mm/rev. and ap=0.2 mm; the lowest flank wear with CBN
cutting insert at cutting conditions of Vc= 150 m/min., f= 0.15 mm/rev. and ap=0.6
mm. With regards to all the three environment criteria, CBN tool displayed a
better performance. It is seen that the greatest problem encountered in turning of
hard pieces is the rapid wear of the tool in a short time. Therefore, when
determining the ideal cutting conditions, cutting speed may be increases to a
degree. Since the first expectations in turning of hard pieces are a good surface
smoothness and also enabling the longest lifetime for the tool, this correlation
should be kept at an optimum level when determining the cutting parameters.
Conclusions
The experiments of AISI S1 material are carried out satisfactorily and the results
obtained from the experiments were evaluated graphically and using ANOVA,
which is one of the statistical techniques.
During the high-speed finishing turning of hardened AISI S1 material, the best
results with regards to surface roughness were obtained with CBN cutters. The
increase in the feed rate value increased the roughness for both cutters. With
regards to turning operations, a roughness value of approximately 0.2 μm was
obtained, which is very good.
For both cutters, while the machining force increased depending on the increase of
the feed rate and cutting depth, it decreased depending on the increase of the
cutting speed With regards to machining force, CBN cutting inserts exhibited
better performance than ceramic inserts.
For CBN and ceramic inserts, the increase in cutting speed increased the flank
wear. With regards to flank wear, CBN cutter exhibited a better performance than
the ceramic cutter for the same cutting parameters.
According to the study of the SEM images, it was determined that effects of
slightly abrasive and intensely adhesive and diffusive wear mechanism are seen in
the ceramic cutter. For CBN cutting inserts, abrasive and intensely adhesive and
diffusive wear mechanisms are seen for the CBN cutters.
According to the ANOVA results, it was seen the change in progress levels is the
most effective parameter on surface roughness (Ra) statistically. It was shown that
the change of tool types did not lead to much change.