Week 8 - Challenge 1 - Draft Analysis on a Fan Cover

When designing plastic-manufactured parts, all faces must have a draft angle of 3 degrees or more, with respect to the tooling access. This ensures the plastic part will be ejected from the mold without friction or interference. In order to check whether the part will be able to be ejected easily or not, a draft analysis is performed.

First and foremost, we must check for continuity; this means checking whether there are any open edges on the part. This can be done by changing the display options in order to highlight open edges in a different color (Tools - Options - Surfaces' Boundaries) or by selecting "Join" and letting the tool highlight all open edges.

Now, we must check the tooling axis. To do this, we first check on the X, Y, and Z directions. The preferred direction will be the one that has a clear view of any holes within the part. After deciding on an initial direction, we then draw the final tooling axis by the bisecting method.

On the two axis perpendicular to the initial tooling axis, we intersect the part in order to check for problem areas (problem areas are the faces which are almost parallel to the tooling axis). We draw a point-to-point line on these problem areas, and then draw a bisecting line between these two lines. We then repeat the procedure for the other axis perpendicular to the tooling direction.

After having these two bisecting lines, we draw a third bisecting line between them. This will be our final tooling direction and will be colored accordingly. When then publish this result, along with the class A surface, and perform the actual draft analysis.

To perform the draft analysis, we click on insert - analysis - feature draft analysis.

Here, we specify the required draft angle (3 degrees in this case)

We then click the compass icon and drag the compass into the tooling direction by the red handle.

Finally, we click on the part and check the draft angle for all faces.

Since the part is green all over, we can conclude all faces meet the minimum draft angle requirement.