This
function allows the user to define a symmetrical die by defining a bilateral
symmetry plane.
Three part
geometry options are available in the Symmetry dialog box.
NO SYMMETRY
(Default)
This is
the default option. All other functions provided in the Symmetry dialog box are
disabled.
SYMMETRY
The part
is defined as symmetrical (the part itself is usually symmetrical).
HALF SYMMETRY INPUT
Only one
half of the part geometry is available. The function will mirror the other half
of the part about a symmetry plane to create a complete part.
There are
three types of symmetry options available. There are described as the
following:
XZ-PLANE
The
symmetry plane is parallel to the XZ-Plane of the Global Coordinate System. The
user must select two points to define the XZ-Plane. The first point is used to
define the location of the symmetry plane, while the second point is used to
define direction of the axis of symmetry.
YZ-PLANE
The
symmetry plane is parallel to the YZ-Plane of the Global Coordinate System. The
user must select two points to define the YZ-Plane. The first point is used to
define the location of the symmetry plane, while the second point is used to
define direction of the axis of symmetry.
TWO-XY-POINTS
The
symmetry plane is normal to the XY-Plane of the Global Coordinate System. The
user must select two points to define the XY-Plane. The first point is used to
define the location of the symmetry plane, while the second point is used to
define direction of the axis of symmetry.
The user can enter the Shift value and click on or
to move the symmetry axis. If the nodes at the
plane of symmetry are not collinear along the symmetry plane, the Align Nodes
function can be utilized to correct the problem. When the part is defined as Half Symmetry,
eta/DYNAFORM will activate the Align Nodes function. The user can define the tolerance input field
to align the nodes along the line of symmetry.
After clicking on this button, the program will pop up an eta/DYNAFORM Question
dialog box, as shown in Figure 6.1.29, and highlight the result from
the operation, as illustrated in Figure 6.1.30. The user can select Yes to
accept the result or select No to correct the inconsistency between some nodes
on symmetry plane and symmetry plane direction within the offset range via
adding align nodes by cursor. The user can also select Abort to redefine the
offset range.
Figure 6.1.29 eta/DYNAFORM Question dialog box
Figure 6.1.30
Highlight nodes
If Half Symmetry
Input is selected, the Mirror Geometry button will be activated. This function
allows the user to select elements, which will be mirrored about the symmetry
plane(s). The Reset button is used to undo the mirror operation.
The
steps needed to define a symmetrical die are listed as follows:
1.
Read
in the symmetrical geometry, mesh it and assign it as Die part.
2.
Select
a geometry type, for example, Half Symmetry.
3.
Select
a symmetry type, for example, Two – X-Y - Points.
4.
Using
the Select Point(s) button to select two points to define the symmetry plane and
the axis direction.
Figure 6.1.31 Half Symmetry Part with XZ-Plane defined by selecting two points
5.
Click
on the Mirror Geometry button. The
mirror result is illustrated in Figure 6.1.32.
Figure 6.1.32 The Mirroring Result
Note: Define the part geometry as Symmetry or Half Symmetry Input, if user click other type of part geometry, the eta/DYNAFORM Question dialog box will pop up below.
Figure 6.1.33 eta/DYNAFORM Question dialog box
Yes
Click the Yes button, the part will restore to the status before define as Symmetry or Half Symmetry Input, without saving the tipping operations, delete created boundary fill features and addendum. For Half Symmetry Input geometry, it will delete mirrored half part same time.
No
Click the No button to exit the dialog box with no operation.