The draw bar menu provides functions to generate draw bars on the die surface.  There are three types of draw bars available:

1.       Draw bar ends with a spherical shape (Tear Drop Head). Figure 7.4.29 shows the control parameters in the dialog box.

Figure 7.4.29  Parameters for Tear Drop Head

2.       Draw bar ends with a conical shape (Tear Drop Tail). Figure 7.4.30 shows the parameters in the dialog box.

Figure 7.4.30  Parameters for Tear Drop

3.       Tear Drop (Draw bar without main body).  Figure 7.4.31 shows the parameters in the dialog box.

Figure 7.4.31  Parameters for Tear Drop

Control Parameters:

Rs: Draw bar Radius

Rf: Fillet Radius

Wh: Wall Height (can be zero)

Sw: Top Strip Width (can be zero)

A:   Wall Angle (default of 6 degrees)

Rt: Tail Circle Radius

Lt:  Length of Tear Drop

The steps to create a draw bar are listed as following:

·         Click on the Draw Bar function from the DFE Modification dialog box to display the Draw Bead dialog box as illustrated in Figure 7.4.32(a).  If the user wishes to define the element size of the draw bar, toggle off checkbox of the Auto Element Size option.  As illustrated in Figure 7.4.32(b), the user can enter the element size in the input field.

·         Select one type of draw bar. The default selection is Draw bar ends with a spherical shape (Tear Drop Head).

·         Click on the Parameters button to display the corresponding dialog box as illustrated in Figure 7.4.29-Figure 7.4.31.

    

   (a) With Auto Element Size              (b) With User Defined Element Size

Figure 7.4.32  Draw bar dialog

·         The Create Draw Bar Surface option enables the user to generate draw bar surfaces.  This option is selected as default.  The user may disable the option if the draw bar surfaces are not required.

·         Define the centerline of the draw bar.  The centerline is the center of the draw bar’s main body, including both ends.

·         If centerline is available in the current database, click on the Select Center Line button to select the centerline. Else, click on the Construct Center Line button to create a line by selecting nodes on the mesh.

·         After the draw bar parameters and centerline are defined, click on the Apply button to generate the draw bar. Select Yes to keep the draw bar mesh or No to reject the mesh.  The Reverse button is used to reverse the draw bar on the opposite side of the tool.  If the Create Draw Bar Surface option is selected, the draw bar surface will be generated together with the mesh.

If the tear drop draw bar is selected, the dialog box as illustrated in Figure 7.4.33 is displayed.  Click on the Select Two Nodes button to select two nodes to define the direction of the centerline. The head of the tear drop will be placed at the first selected node. The length of the tear drop is determined by the parameters defined in the Parameter window.

Figure 7.4.33  Tear Drop

Figure 7.4.34 shows the details of three types of draw bars.

Figure 7.4.34  Three Types of Draw bars