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发表于 2008-4-11 21:02:19
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求助帮助翻译模具英语
Since wrinkles are formed because of excessive metal flow
in certain regions, where the sheet is subjected to large compressive
stresses, a straightforward method of eliminating the
wrinkles is to add drawbars in the wrinkled area to absorb the
redundant material. The drawbars should be added parallel to
the direction of the wrinkles so that the redundant metal can
be absorbed effectively. Based on this concept, two drawbars
are added to the adjacent walls, as shown in Fig. 9, to absorb
the excessive material. The simulation results show that the
wrinkles at the corner of the step are absorbed by the drawbars
as expected, however some wrinkles still appear at the remaining
wall. This indicates the need to put more drawbars at the
draw wall to absorb all the excess material. This is, however,
not permissible from considerations of the part design.
One of the advantages of using finite-element analysis for
the stamping process is that the deformed shape of the sheet
blank can be monitored throughout the stamping process, which
is not possible in the actual production process. A close look
at the metal flow during the stamping process reveals that the
sheet blank is first drawn into the die cavity by the punch
head and the wrinkles are not formed until the sheet blank
touches the step edge D–E marked in Fig. 1(b). The wrinkled
shape is shown in Fig. 10. This provides valuable information
for a possible modification of die design.
An initial surmise for the cause of the occurrence of wrinkling
is the uneven stretch of the sheet metal between the punch
corner radius A and the step corner radius D, as indicated in
Fig. 1(b). Therefore a modification of die design was carried
out in which the step corner was cut off, as shown in Fig.
11, so that the stretch condition is changed favourably, which
allows more stretch to be applied by increasing the step edges.
However, wrinkles were still found at the draw wall of the
cup. This result implies that wrinkles are introduced because
of the uneven stretch between the whole punch head edge and
the whole step edge, not merely between the punch corner and
the step corner. In order to verify this idea, two modifications
of the die design were suggested: one is to cut the whole step
off, and the other is to add one more drawing operation, that
is, to draw the desired shape using two drawing operations.
The simulated shape for the former method is shown in Fig.
12. Since the lower step is cut off, the drawing process is
quite similar to that of a rectangular cup drawing, as shown in
Fig. 12. It is seen in Fig. 12 that the wrinkles were eliminated.
小弟英语不行,特来求助各位大大帮小弟一下,帮小弟翻译一点!!!
在这你谢谢各位大大了!! |
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