Week 8 - Challenge 3 - Switch Bezel Design

AIM:

Create the Switch Bezel Plastic component through the given Class-A surface. And perform the Draft analysis on the model.

OBJECTIVE:

• Create Class B and C surfaces through Class A surface.
• Create tooling axis using the bisecting method.
• Perform draft analysis.

THEORY:

Draft Analysis:

Draft analysis helps to detect if your drafted part is easily removable from the mold (in case of the plastic component) or die (in case of sheet metal). All plastic components will have a minimum draft of 0.5 to 3deg. And for automotive sheet metal parts the draft will be 7deg or more. If a mold wall is perpendicular to the part ejection, there is ample friction or interference between the mold and the part which will not allow one to release from the other. This is why design engineers give a minimum draft to the part.

In CATIA V5 the feature draft analysis dialog box look like this:

Mode:

• The mode option lets you choose between quick analysis and full analysis mode.
• In quick mode there are 3 ranges with blue, red and green colors. In the case of plastic component we will set the draft angle as 3deg.

Display:

• The first box is to open and close the color scale dialogue box.
• The second box is the analysis under running point, when activating the checkbox and move the pointer over the surface. This option enables you to perform local analysis. Arrows are displayed under the pointer, identifying the normal to the surface at the pointer location (green arrow), the draft direction (red arrow), and the tangent (blue arrow). As you move the pointer over the surface, the display is dynamically updated. Furthermore, circles are displayed indicating the plane tangent to the surface at this point. The displayed value indicates the angle between the draft direction and the tangent to the surface at the current point.
• Click the No Highlight Representations button to set the display option of highlight effect sources as "on/off". When checked "On" the surfaces are selected but they will not be seen in the specification tree.
• Click the Light Effect button and the colors of the analyzed elements react to the light source

Direction:

• The first check box is the locked direction icon which is used to lock the direction of the compass after selecting the specified direction.
• Click on the compass icon to specify the new pulling direction to remove the part.
• Click the Inverse button to automatically reverse the draft direction. When several elements are selected for analysis, the draft direction is inverted for each element when the button is clicked.

Tooling Direction:

The Tooling Direction is basically the direction that the mold pulls apart. The mold is built in two separate pieces, basically. You have a Cavity side and you have the Core side. The Core pulls apart from the Cavity and that's the Dyeline or the Tooling Direction. There are different methods to find out the tooling direction. Here we are using bisecting method to find out tooling direction. We can use any method the ultimate aim is to reduce the cost of manufacturing by reducing the complicity in manufacturing the component.

PROCEDURE:

The procedure is divided into two parts first creating the tooling axis then performing the draft analysis.

Creating tooling axis using the bisecting method:

• The first thing to do is finding out the possible tooling direction by visually checking the part. Rotate the part in all direction and find out the most suitable direction for tooling. Here in this case viewing from Z direction we can clear the face in tooling.
• Then we create a point on the base surface of the part. On this point we put a new axis system.
• Then we are finding out the tooling axis in X direction. For that intersect command is used to get the boundary in X direction or XZ plane. Since we got only one wall through the intersection for bisecting the line we need 2 walls. For that we create another line of 9deg from the existing wall inside a sketch. The angle is obtained by the trial and error method.

• Extending the drafted face using a point-to-point line command. Then using bisecting line command bisect both extended line and newly created line, to get the tooling axis in X direction.
• To find out tooling axis in Y direction intersect command is used to create a boundary in YZ plane. Extending the drafted face using a point-to-point line command. Then using bisecting line command bisect both extended lines to get tooling axis in Y direction.

• After that both tooling axis are bisected to create the main tooling axis.

Performing the draft analysis:

• Open Feature draft analysis option from Insert > Analysis > Feature draft analysis.
• A new window pops up by default it will be in quick analysis mode. Change the range to 2.9deg.
• Next you have to position the compass on the tooling axis by dragging the compass from the top right corner of the working area. The W axis of the compass should be inline with the main tooling axis.
• Then you have to define the compass by click on compass icon on the draft analysis window. Then lock the position of the compass by clicking the lock icon.
• After that select the surface and the whole surface will show a color range. For a good draft make the surface fully green.

RESULT FOR DRAFT ANALYSIS:

Report for the CLASS A surface:

Report for the Final plastic component:

Screenshots of the solid model with the proper color code of the draft angle in various orientations:

FIG: Isometric View

FIG: Front View

FIG: Side View

FIG: Top View