Week 8 - Challenge 1 - Draft Analysis on a Fan Cover
DRAFT ANALYSIS- FAN COVER
AIM
The Challenge aims to define the tooling axis for the given fan cover model and perform the draft analysis and make a report.
THEORY
DRAFT:
Drafting is a technique in which a slant angle is given to the injection molded parts so that the pulling operation becomes easy and increases the tool and product life. The draft also decreases the cost of production and lead time (since the operation becomes easy). The amount of draft angle given varies from product to product depending on the designer and manufacturer's interests but a minimum amount of draft angle needs to be maintained.
PROCEDURE
1. CHECKING THE CLASS-A SURFACE:
The first step that we need to do is to check the continuity of the given class-A surface. This can be done by the feature JOIN/ BOUNDARY. If any irregularities or discontinuities are found, those are to be rectified.
2. DEFINE TOOLING AXIS
The next step is defining the tooling axis. For this first, we need to decide on a temporary tooling direction among X, Y, Z axes. The temporary tooling direction must be selected considering all the feasible conditions like least side core and ease of ejection. Now we need to construct the tooling direction for the sketch in the ZX plane by constructing a bisecting line for the slant edges and the same must be carried out for the sketch in the ZY plane. Now the final tooling axis which is the line bisecting the tooling directions for sketches in ZX and ZY planes must be constructed.
Dummy tooling direction:
For clearing in X-direction: For clearing in X-direction:
Final tooling direction:
3. DRAFT ANALYSIS
The final step, the draft analysis concerning the tooling axis defined in the previous step, is carried out and the results are obtained. The minimum draft angle for this fan cover is taken as 3 degrees.
FINAL MODEL
ISOMETRIC VIEW TOP VIEW
FRONT VIEW SIDE VIEW
Detailed Tree structure:
