Influence of Different Abrasives Mixtures on Abrasive Water …
517
the jet to produce the sufficient material removal rate at top, middle, and bottom
cutting regions. Similarly, a lower circularity was found in 60:40 abrasive mixture
rather than garnet abrasives. This was obtained while the stand-off distance of 3 mm
employed. Mixed type abrasives cause the uniform rate of material removal in the
cutting regions as a result of angular and spherical shaped particles maintains the
cutting energy throughout the depth of target material. Among the experimental
conditions, the highest circularity variation was found with the garnet abrasives. It
is also observed that stand-off distance influences the circularity of the holes. Lower
stand-off distance has produced a higher circularity variation in all types of abrasive
conditions. This was due to the employment of a lower stand-off distance produced
higher kinetic energy which removes the more volume of material at the entry region
compared to the other regions.
3.3 Cylindricity
Table 4 shows the cylindricity values for the various machining conditions with
different stand-off distances. The comparison of cylindricity variations is shown in
Fig. 5. These values were measured at entry and exit regions of the drilled holes. This
geometrical tolerance measures that govern the overall form of a cylindrical feature
to confirm that it is circular and straight along with the hole axis. The results reported
that 60:40 abrasive mixture produced a least cylindricity variation in the AWJ drilled
holes. In addition, the angular shaped abrasives maintain the cutting energy of the jet
which results in drilled hole round variations are significantly reduced. These results
confirmed that 60:40 abrasives mixture maintains the circularity through an entire
cylinder length.
Table 4 Cylindricity of drilled holes
S. No.
Abrasive
Standoff distance (mm)
Cylindricity (mm)
1
Silicon carbide
5
0.169
2
3
0.202
3
1
0.282
4
Garnet
5
0.304
5
3
0.416
6
1
0.542
7
Garnet-silicon carbide (60:40)
5
0.231
8
3
0.032
9
1
0.346
517
the jet to produce the sufficient material removal rate at top, middle, and bottom
cutting regions. Similarly, a lower circularity was found in 60:40 abrasive mixture
rather than garnet abrasives. This was obtained while the stand-off distance of 3 mm
employed. Mixed type abrasives cause the uniform rate of material removal in the
cutting regions as a result of angular and spherical shaped particles maintains the
cutting energy throughout the depth of target material. Among the experimental
conditions, the highest circularity variation was found with the garnet abrasives. It
is also observed that stand-off distance influences the circularity of the holes. Lower
stand-off distance has produced a higher circularity variation in all types of abrasive
conditions. This was due to the employment of a lower stand-off distance produced
higher kinetic energy which removes the more volume of material at the entry region
compared to the other regions.
3.3 Cylindricity
Table 4 shows the cylindricity values for the various machining conditions with
different stand-off distances. The comparison of cylindricity variations is shown in
Fig. 5. These values were measured at entry and exit regions of the drilled holes. This
geometrical tolerance measures that govern the overall form of a cylindrical feature
to confirm that it is circular and straight along with the hole axis. The results reported
that 60:40 abrasive mixture produced a least cylindricity variation in the AWJ drilled
holes. In addition, the angular shaped abrasives maintain the cutting energy of the jet
which results in drilled hole round variations are significantly reduced. These results
confirmed that 60:40 abrasives mixture maintains the circularity through an entire
cylinder length.
Table 4 Cylindricity of drilled holes
S. No.
Abrasive
Standoff distance (mm)
Cylindricity (mm)
1
Silicon carbide
5
0.169
2
3
0.202
3
1
0.282
4
Garnet
5
0.304
5
3
0.416
6
1
0.542
7
Garnet-silicon carbide (60:40)
5
0.231
8
3
0.032
9
1
0.346