Week 8 - Challenge 1 - Base Bracket Design
Report:
Introduction:
Draft Analysis is the process of assessing the designed plastic part if it has the drafting angles as per the requirement. In CATIA, draft analysis is done by the tool called Feature Draft Analysis. It shows the different draft angles available at different parts and says if it meets the requirement or not by various color codes. In this example, a base bracket’s class-A surface is taken for the draft analysis study.
Objective:
To perform the draft analysis of a base bracket using CATIA V5.
Steps involved:
1) Determining and making the Tooling Axis
- Checking the boundary
The given part is first checked for its boundary to find if there is any gaps or opening or discontinuity in the boundary. If there is more than one boundary because of the openings, they can be separated.
- Insert a coordinate system
In order to perform the other steps, first, insert a point at almost the symmetric center of the part and insert a coordinate system at the point. The coordinate system should be facing in all directions same as the default coordinate system.
- Determining the tooling axis
By looking at the part from the various direction, the optimum tooling axis is determined taking into consideration of various factors such as low cost, avoiding side cores, etc.
- Intersect with xz plane
After determining the tooling axis, to make the tooling axis, we need to take the intersection of the part in two directions other than the tooling axis. First, xz plane is used to find the intersection curve. Then it is looked for the curve elements which can possibly create problems while ejecting the part. The curves which are almost perpendicular or have a high angle with the tooling axis can create no problem as they can be easily ejected. On the other hand, if the intersection curve has some elements which are almost parallel or has a small angle with the tooling axis, then it should be assessed using the bisecting line.
- Creating the dummy tooling axis
Before actually creating the tooling axis, a dummy tooling axis is created using the help of the point created earlier.
- Creating lines from steep curve elements
As explained earlier, those elements of the intersection curve which appear to be parallel with the dummy tooling axis should be assessed. To do it, their endpoints are taken and a line is drawn through them. It is done on both sides of the axis.
- Creating the tooling axis
Now, using the two steep lines, use the bisecting line to create a new line (tooling axis) and select the result in the required direction. This will give the tooling axis we require. It can be made bold and the color can be changed for its better visibility.
2) Publishing the base bracket and the tooling axis
Publishing elements in CATIA V5 are used for various purposes. It helps to make the references of the part as a datum entity of the part. Here, the base bracket surface and the tooling axis are published. (The following screenshot of published surfaces contains all the elements required to publish; Tooling axis, Class A surface, B surface, and C surface.)
3) Perform Draft Analysis
Now, perform the draft analysis of the base bracket. To do so, go to tools > analysis > Feature Draft Analysis. This tool has three groups of options namely; mode, display, and direction. First, the second icon from the direction group is selected and the red dot in the compass is clicked and dragged to the part to be drafted. The line in the dragged element is matched with the tooling axis and it is locked using the first icon in the direction group. It will define the tooling axis direction and lock it. Then click the base bracket. It will turn green or with green and red based on the draft angles. If the minimum draft angle is set to 3 and we have only 2 degrees of draft angle, it will show that portion in red. If the portion has enough draft angle, it will show it in green. Thus, the draft analysis is complete.
Submission Requirements:
- Screenshots of the Draft analysis report for both the given Class-A surface and the final plastic component
- Image of the complete Draft analysis:
- Images of the color scale variant:
- Screenshots of the solid model with the proper color code of the draft angle in various orientations (Isometric, Front, Side, and Top View)
Isometric:
Front:
Left Side:
Right Side:
Top View:
Expanded Specification Tree (after completion of all steps):
