Abstract :
The CNC machining industry is used to work products with complex surface shapes
and accurate precision. In the milling process, surface roughness is very important.
In this study, the CNC milling process was carried out on aluminum material with
variations in feed per tooth and spindle rotation speed. The purpose of this study
was to determine whether or not the variation of feed per tooth and spindle rotation
speed on the surface roughness test of aluminum with the clarification of the RAL
ANOVA method and to determine the combination of feed per tooth and spindle
rotation speed that resulted in the roughness value of aluminum. This study uses
SPSS software on the CRD method (Completely Randomized Design). Parameters
that were varied were feed per tooth 0.02 mm, 0.04 mm, and 0.06 mm with spindle
rotation speed of 3500 Rpm, 4500 Rpm, and 5500 Rpm. Variations in feed per tooth
and spindle rotation speed have an effect on surface roughness. The results of the
RAL method using SPSS show the effect on variations in feed per tooth, variations
in spindle rotation speed, and the combination of feed speed per tooth with spindle
rotation speed can be seen from the sig value, which is 0.000, which is smaller than
the sig level = 0.05. It is stated that this variation has a significant effect on surface
roughness. So it was proven to use feed per tooth variations which were more
influential with a calculated F result of 281.452, while the variation in spindle
rotation speed with a calculated F result of 89.301, and a combination of feed
variation per tooth with spindle rotation speed with a spindle rotation speed with a
calculation F result of 52.281 was greater than F table 0.05. The combination of
feed per tooth and the rotational speed of the CNC milling spindle increases the
surface roughness value. The results of the CNC milling process have the highest
roughness value, namely 0.943 m at feed per tooth 0.06 mm at a spindle speed of
4500 Rpm and the lowest at 0.281 m at a feed per tooth 0.02 mm at a spindle speed
of 4500 Rpm. Then the roughness value already meets the standards that can be
carried out by the CNC milling machining process.