Week 9 - Challenge 1 - Base Bracket Design

AIM:

To create the Base Bracket Plastic component through the given Class-A surface. To begin with, the tooling axis for the given Class-A Surface should be created meeting the requirements of the draft angle and at the end perform the Draft analysis on the model.

CAD DATA:

The CAD DATA is been given as CATPART,STEP FILE ICES PART

Solution:

INTRODUCTION:

CLASS-A SURFACE: a surface made by the designer which is given as an input to the plastic modeler to work on. It is aesthetic surface and the outer most surface.

CLASS-B SURFACE: a surface below a certain thickness from the class-A surface is class-B surface. This is the surface that contains engineering aspects of a model.

CLASS-C SURFACE: a surface that joins class-A and class-B surfaces is class-C surface.

METHODOLOGY:

In this model we have focused on the following things:

1. Tooling axis
2. Draft analysis
3. Class-B surface
4. Class-C surface
5. Making a solid model from surface.

Following tools were used to reach the final step:

1. Extract
2. Un-trim
3. Trim
4. Extrapolate
5. Offset
6. Edge fillet
7. Boundary
8. Sweep
9. Join
10. Close (part design)

Specifications:

Base Bracket Thickness = 2.5mm

Minimum Draft Angle = 3 Degrees

1. FOR TOOLING AXIS:

First ensure the class-A surface is properly joined and has no discontinuity on it. For this we can use boundary command or join command.

Analyze the model manually or visually to see which direction is most suitable for tooling axis.

As in 3D view we can see 2 holes and a flat surface, we can directly take the tooling axis perpendicular to that. But to be sure,let us analaze from all the views. The below images of the front side and top views shows the areas that we have to keep in mind while choosing tooling axis. As from X we cannot see one hole so we cannot take axis along this. In Y we cannot see any holes so here too we cannot take tooling axis. But in Z we can see 2 holes and flat surface so we can take tooling axis.

Create the Base Bracket Plastic component through the given Class-A surface. To begin with, the tooling axis for the given Class A Surface should be created meeting the requirements of the draft angle and at the end perform the Draft analysis on the model.

REPORT ON DRAFT ANALYSIS:

Given Class A Surface:

STEP 1: Check the connectivity of the Class A Surface
Ensure that there is no gap between the component, using join command.
We can visually check it or by clicking boundary command.
It has 3 boundaries one outer and two inner circle boundaries.
Therefore first check completed.

STEP 2: Find the tooling axis of the component. The tooling axis is nothing but the mould opens or cavity opens.
Check visaully which is the best possible tooling axis.
Check all three axis.
Along x it possible but expensive and y is not possible.
z is the best possible tooling axis.

Creating a Tooling axis along z:

Therefore the main tooling axis is along z axis.
Now perform the Draft analysis using the Featured Draft Analysis tool in the tools.
Then after opening the draft analysis tool box go for the compass and place the compass alinged to tooling axis and click on the lock symbol after alinging and further click on the surface.

Now creating Class B Surface:

Intially extracting the right side rib using extract option from Class A surface.

Then perform Extrapolate inorder to increase the length

Now trim the surfaces to required surfaces

Then Offset the surface inorder to get the required thickness

Similary create the left side rib

Now Similarly get the slanted as well as the flat surface and offset it to desired value

And now trim inorder to get the required surface

Now fillet the surface to required amount

Now Creating Class C Surface:

EXPLANATION ON BISECTING METHOD:
Bisecting method is basically use to find the proper tooling axis using the dummy tooling axis. In Bisecting method, bisecting line is used which either bisect the two line or it will show error which means the two lines are parallel to each other. In order to know whether the particular surface is toolable or not we intersect the surface with the respective plane and get a sketch which consist of two lines and with the help of bisecting line option we bisect the line which creates a line at the mid point of the two lines. Like wise we create tooling clearing axis for x and y which will be used to create the main tooling axis using the bisecting line option in in the line comand.