Week 8 - Challenge 1 - Base Bracket Design

AIM:

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

OBJECTIVES:

To model a base bracket and perform draft analysis on the model.

THEORY:

Draft Analysis:

Draft analysis helps to detect if your drafted part is easily removable from the mold (in case of 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.

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 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 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 surface of the part, we can create the point anywhere on the surface but usually we take CG point or take a point near to centre. 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.
• Extending the drafted face using a point to point line command. Then using bisecting line command bisect both extended line to get tooling axis in X direction.
• Since in Y direction there is no wall to create bisect. We finalise the tooling axis in X direction as 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 3deg.
• Next you have to position the compass on the tooling axis by dragging the compass from top right corner of the working area. The W axis of the compass should be inline with the axis.
• Then you have to define the compass by click on compass icon on the draft analysis window. Then lock the positon of the compass by clicking the lock icon.
• After that select the surface and the whole surface will shows a color range. For a good draft make the surface fully green.