TIPPING

In most stamping simulations, the global Z direction is selected as the stamping direction.  Some product design might not be compatible with the default setting of eta/DYNAFORM. Therefore the tipping function is used to adjust the product to follow the stamping direction. It allows the user to translate and/or rotate the part about a defined axis. The TIPPING dialog box is illustrated in Figure 6.1.58.

 

Figure 6.1.58  Tipping interface

 

Before tipping, there are some parts already existing in the part list, as shown in Figure 6.1.58. When defining some parts as DIE in the previous DEFINE interface, the program automatically adds these parts into the Include Part List on Tipping interface.

 

6.1.3.1  TIPPING WITH THE GEOMETRY

If the checkbox of this option is toggled on, eta/DYNAFORM will tip all the parts that are defined as DIE. All geometry in DIE including surfaces, lines and elements will be rotated and translated.

 

6.1.3.2  TIPPING WITH ALL PARTS

If the checkbox of this option is toggled on, eta/DYNAFORM will tip all the parts in the active database. All geometry including surfaces, lines and elements will be rotated and translated.

 

6.1.3.3  INCLUDE PARTS LIST

This function allows the user to add the parts that need tipping into the list using ADD button. The user can also delete the unnecessary parts using REMOVE button. After tipping, the ADD and DELETE buttons are disabled so that the user cannot add or delete parts.

 

6.1.3.4  DEFINED TIPPING

Figure 6.1.59  Record and Restore the Defined Result

 

This function is used to record and restore the tipping operation. The ADD function is used to record the tipping result. The REMOVE function is used to remove one record.  The LOAD function is used to restore the tipping result to the selected record.

 

6.1.3.5  TIPPING CHECK

This function allows the user to check the result after tipping operation, as shown in Figure 6.1.60.

Figure 6.1.60  Check tipping

 

l  PART DEPTH

This function displays a contour plot showing the draw depth of part relative to the binder.  Different draw depths are displayed in graduated colors on the die.  Draw depth is estimated with reference to the first point of punch/die contact.  When the die/punch is closed, the first point on the blank to contact with the punch is locked.  The rest of the part will be stretched from this point spreading outward.

 

l  UNDERCUT

This function displays a contour plot showing regions in the die with undercut. Red indicates severe under cut where the backdraft is less than 0º. Yellow indicates a marginal area with a draw angle of approximately 0~3º.  Green indicates a safe region with a draw angle that is greater than 3º. The user can set the threshold for marginal and severe backdraft. Click  button to display a dialog box as illustrated in Figure 6.1.61.

Figure 6.1.61  Undercut Limit dialog box

 

l  WALL ANGLE

Once this option is selected, the program displays a contour plot showing wall angle on the die. Different wall angles are displayed in different colors. The user can point the cursor to any node on the selected part and click on the left mouse button to show the wall angle at this node, as illustrated in Figure 6.1.62.

Figure 6.1.62  Display Wall Angle

 

 

6.1.3.6  TIPPING CENTER

This function is used to define location of tipping center.  

 

          DEFAULT - The default tipping center is set at center of mass. 

          USER DEFINE - The user selects a node, point or center coordinate as the tipping center using the INPUT COORDINATE dialog box as illustrated in Figure 6.1.63.

Figure 6.1.63  Selection of Tipping Center using INPUT COORDINATE dialog box

 

6.1.3.7  DIRECTION

This function allows the user to define tipping direction, click on this button to display Define Direction dialog box, as shown in Figure 6.1.64.

Figure 6.1.64  Define Direction dialog box

 

l  USER DEFINE

This function allows the user to define tipping direction by defining vector. Refer to Section 5.1.4 Shortest Curve for detailed description on defining vector.

 

l  SURFACE NORMAL

This function allows the user to define tipping direction via the normal of the selected surface.

 

6.1.3.8  AUTO-TIPPING

This function automatically converts the die to stamping position by averaging all normal vectors of elements to minimize undercut and draw depth.

  

Before Tipping                              After Tipping

Figure 6.1.65  Tipping Check

NOTE: eta/DYNAFORM will automatically compute the tipping center. A default local coordinate system is created at the tip center with the UVW direction that is consistent with XYZ of the global coordinate system. The W axis is always set as the drawing direction. The functions on the tipping dialog box rotate the die so that the W axis is set as the drawing direction.

 

6.1.3.9  MANUALTIPPING

In addition to the automatic tipping function described in Section 6.1.3.8, the user can manually tip the die about U, V, and W axes to a better draw direction. This function is very useful when auto-tipping does not provide a satisfactory tip result due to unbalanced mesh pattern or part shape. 

 

In manual tipping operation, the DIE can be rotated/translated about/along the U-, V-, or W-axis, as shown in Figure 6.1.66.   Using the rotation/translation about/along the U-, V-, or W-axis to perform the tipping operation according to the increment defined in the dialog box. The tipping check will be visible if the checkbox for UNDERCUT or DRAW DEPTH button is toggled on.

Figure 6.1.66  Manual Tipping

 

          ROTATION

    Select ROTATION AXIS and key in any absolute rotation angle in the input field.  Click on 2 or 3 button that represents the rotation axis to rotate the model with defined angle about the selected axis.

 

          TRANSLATION

    If TRANSLATION AXIS option is selected, the 1 or 4 button represents translation direction.  The value in the input field of TRANSLATION is the incremental displacement along the selected axis.

 

6.1.3.10   UNDO AND RESET TIPPING OPERATION

The UNDO function will cancel the last performed tipping operation, while the RESET function will cancel all tipping operations.