Week 8 - Challenge 1 - Base Bracket Design

Report:–

Objective:

• The main objective of this challenge is to create the Base Bracket Plastic component through the above-given Class-A surface, by giving the Tooling axis and 'Draft analysis' to the class-A surface of the base bracket.

TOOLING AXIS:

• We should deeply observe and study the class A surface to create the 'Tooling Axis' for the component, for the above-given base bracket Z-axis is the best suitable tooling axis. Initially, I created a dummy tooling axis on Z-axis by considering the reference point created in the middle of the circle

There are 3 types of Tooling axis can created based on giving model,

1. Point To Direction
2. Bisecting Method
3. Normal To Surface

DRAFT ANALYSIS:

The draft analysis technique is used to analyze whether our part model created in CAD is manufacturable based on the draft condition applied. Here the part should get easily removed from the panel Mold in case of plastic core and cavity

To perform draft analysis

click on Insert >>Analysis >> Feature Draft Analysis

• Once the draft analysis toolbar is opened, go to the display block and select the 'Analysis under the running point' command to check the angle for different sides (ribs and inclined plane angles) on the class A surface. The color scale on the bottom visualizes, whether the draft angle meets the requirements or not (3 deg) by indicating the colors Green, Blue and Red. Once the draft angle analysis was done, we need to align and fix the compass to the tooling axis of the class A surface.

MATERIAL SELECTION:

Polypropylene

• Polypropylene is used the most frequently of any plastic in automotive manufacturing. Being a thermoplastic polymer, it can easily be formed into almost any shape. It has excellent chemical and heat resistance and is generally resistant to impact.

CLASS B SURFACE:

B surface means thickness of a part it is not visible it is inside part. It will shows that core side of the plastic model.

• To create the class B surface, I considered the entire surface has 3 parts 'Rib-1, Rib-2, and Base surface'. If we directly offset the class A surface, fillets may lead to cause an error, to avoid the errors we need to extract the surfaces and untrim the extracted surfaces and extrapolate those untrimmed surfaces with point continuity. Now trim those extrapolated surfaces to the required shape. And finally, fillets were given to the final trim.

OPERATION'S in Class B Surface:

1. Extract & Untrim
2. Offset & Trims
3. Fillets

Class C Surface:

The Class C finish allows more imperfections than Class A or B. Class C is often specified for interior surfaces not readily visible, surfaces that will be covered by another part when assembled, or surfaces which the Customer feels do not need to meet a high cosmetic finish.

• It is the combination of Class A, Class B and Class C surfaces. To create a class C surface, I used the sweep command by considering the outer boundary of the class A surface. In the sweep command, go to the 'line' command in the 'profile' block and the subtype is 'with draft direction'. Now select the outer boundary and tooling axis, give 3 deg in the angle (the draft angle for a plastic component is 0.5 to 3 deg) and select the direction to sweep, in this condition the class B surface is under the class A surface so select the inside down arrow to sweep. The same procedure is repeated for the two circles on the class A surface.

OPERATION'S in Class C Surface:

1. Boundary
2. Smooth curve
3. Sweep
4. Extrapolate
5. Trim

Final Trim (closed body):

• Now I joined all the swept surfaces by using the 'join' command and then I trimmed the Class A, Class B and Class C surfaces to make a closed surface, to make a Solid body.

SOLID BODY:

DRAFT ANALYSIS:

• To align and fix the compass to the tooling axis, go to the Direction block in the draft analysis toolbar and click on the 'Use the compass to define the new current draft direction option (or just click on the compass symbol). Now bring the compass to the surface and align it to the tooling axis of the class A surface and click on the lock symbol beside the compass in the direction block. Once we click on 'ok' on the draft analysis toolbar, we can finish the draft analysis process.

TREE STUCTURE: