High Precision Finish Cutting
by Dry WEDM
Masanori Kunieda(2), Chika Furudate
Department of Mechanical Systems Engineering
班級：機研一甲
學號：M9510215
學生：李俊承
Outline
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INTRODUCTION
EXPERIMENTAL METHOD
COMPARISON OF MACHINING CHARACTERISTICS
IMPROVEMENT OF MACHINING CHARACTERISTICS
CONCLUSIONS
INTRODUCTION
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In dry-WEDM, the gap distance is narrower than that in
conventional WEDM using dielectric liquid, and there is
no corrosion of the workpiece, high accuracy in finish
cutting can be realized in dry-WEDM.
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That dry-WEDM produces excellent straightness of the
finished surface but material removal rate is lower than
conventional WEDM.
EXPERIMENTAL METHOD
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In WEDM, unfavorable streaks are in some cases
generated parallel to the wire as shown in Figure 1(a).
EXPERIMENTAL METHOD
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Figure 2 shows the measured waviness of a surface
finished by dry-WEDM.
COMPARISON
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Figure 3 shows the difference in straightness between
conventional and dry-WEDM.
COMPARISON
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Figure 4 shows a comparison of surface roughness
obtained from the same experiment in the previous
section.
COMPARISON
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Figure 5 shows the difference in the gap length.
COMPARISON
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The working conditions used were the same as in
Table 1 except for the wire electrode diameter of
200μm. The discharge current was 110A.
COMPARISON
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The frequent occurrence of short-circuiting due to the
narrower gap length in dry-WEDM causes unfavorable
repetition of the turning back and forth of the wire
electrode in the feed direction.
COMPARISON
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From the profiles measured in the direction θ=1°, more
streaks were however seen generated over the dryWEDM surface than the conventionally WEDM surface.
IMPROVEMENT
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The higher the wire winding speed, the higher the
material removal rate and the better the straightness
will be.
IMPROVEMENT
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It was found that the material removal rate is higher
when the air pressure is increased.
The high-velocity airflow deteriorated the straightness.
IMPROVEMENT
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Figure 11 shows the influence of air pressure on the
actual depth of cut measured and gap length.
The actual depth of cut decreases with increasing air
pressure.
IMPROVEMENT
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When the actual depth of cut was smaller than 1.5μm,
there were no visible streaks over the finished surface.
CONCLUSIONS
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Comparisons of machining characteristics between
conventional and dry-WEDM showed that dry-WEDM
offers advantages such as better straightness, surface
roughness, gap length, accuracy in corner-cut, and
electrolytic corrosion-free.
It was also found that dry-WEDM has poorer material
removal rate and waviness.
the material removal rate and waviness can be improved
by increasing the wire winding speed and decreasing the
actual depth of cut.