Week 9 - Challenge 1 - Base Bracket Design

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

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

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

First Step

We have to create the tooling Axis. For the tooling axis First ensure the class-A surface is properly joined and has no discontinuity on it. For this, we can use the boundary command or join command.

Analyze the model manually or visually to see which direction is most suitable for the 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 analyze from all the views. The images below of the front side and top views show the areas we must keep in mind while choosing the tooling axis. As from X, we cannot see one hole so we cannot take the axis along this. In Y we cannot see any holes, so we cannot take the tooling axis here too. But in Z we can see 2 holes and a flat surface so we can take the tooling axis.

View From X-Axis

View From Y-Axis

View From Z-Axis

Now creating a dummy tooling axis

Now creating the plane parallel to point 1 for intersection with our Class A surface

Intersect the ZX plane of the axis system with the input and we can see that no surface can create problems during tooling in this direction.

Intersect the ZY plane and we are unsure of these two surfaces, so we make a line and bisect them both this will be our tooling axis which, not so surprisingly, is the same as our guessed tooling axis. 

 

FOR DRAFT ANALYSIS:

1. Go to insert< analysis< feature draft analysis.

2. Align the tooling axis with the compass.

3. Click on the surface and see that the surface is within the permissible limit of the draft values.

4. The surface should be green and in the column proper value (3deg) should be inserted.

 

 

 

FOR CLASS-B SURFACE:

Here we divide the surfaces into different parts for better understanding purpose

FLAT SURFACE:

1. Extract the flat surface.

2. Un-trim the surface.

3. Extrapolate it.

4. Offset it by 2.5mm i.e. thickness.

SLANT SURFACE:

1. Extract the slant surface.

2. Un-trim the surface.

3. Extrapolate it.

4. Offset it by 2.5mm i.e. thickness.

RIBS SURFACES:

1. Extract the rib surfaces (1 rib at a time).

2. Un-trim the surface.

3. Extrapolate it.

4. Offset it by 2.5mm i.e. thickness.

5. Trim to get the desired shape.

6. Repeat the above steps for the second rib too. The final rib output with trimming is shown below

Once we have finished doing this, we have to trim the surface to get the exact shape of the class-A surface (without fillet) below 2.5mm. After the trimming part is done, fillet the model. The formula for filleting= fillet value-thickness (if the Filleting surface is contracting). We get our class-B surface.