Week 8 - Challenge 1 - Base Bracket Design

Week 8 - Challenge 1 - Base Bracket Design

AIM: To create the Base Bracket Plastic component through the given Class-A surface.
INTRODUCTION:
CLASS-A SURFACE: A surface created by the designer that the plastic modeler uses as an input. It is the most exterior and aesthetically pleasing surface.
CLASS-B SURFACE: Class-B surfaces are those that are thinner than class-A surfaces. This is the area of a model where the engineering components are located.
CLASS-C SURFACE: Class-C surfaces are those that connect class-A and class-b surfaces.
METHODOLOGY:
In this model we have focused on the following things:
• Tooling axis
• Draft analysis
• Class-B surface
• Class-C surface
• Making a solid model from the surface.
The following tools were used to reach the final step:
• Extract
• Un-trim
• Trim
• Extrapolate
• Offset
• Edge fillet
• Boundary
• Sweep
• Join
• Close Surface (Part design)

FOR TOOLING AXIS:
1. Make sure the class-A surface is first properly connected and free of any discontinuities. The use of the boundary command or the join command is possible here.
2. Examine the model manually or visually to determine the best direction for the tooling axis.
3. Since there are two holes and a flat surface visible in the 3D image, the tooling axis can be taken immediately perpendicular to that. But let's analyze from all angles just to be sure. The front side and top views of the images below indicate the points to consider while selecting a tooling axis. We cannot take an axis along this since from X we cannot see a single hole. Since we cannot see any holes in Y, we are also unable to determine the tooling axis. However, in Z there are two holes and a smooth surface, thus we can determine the tooling axis. \

4. There are no surfaces that could cause issues during tooling in this direction when the ZX plane of the axis system is intersected with the input, as can be seen.

5. Intersect ZY plane. Since we don't know which of these two surfaces intersects the ZY plane, we draw a line through them both to determine the tooling axis, which, not surprisingly, coincides with our guessed tooling axis.

6. Bisecting Method – In essence, the bisecting approach is used to identify the correct tooling axis using a false axis. In the bisecting method, a bisecting line is utilized, and either it bisects the two lines or an error is displayed, indicating that the two lines are parallel. In order to determine whether a specific surface is toolable or not, we intersect the surface with the appropriate plane and obtain a sketch that consists of two lines. Using the bisecting line option, we then divide the sketch into two lines, creating a line at the intersection of the two lines. To establish the main tooling axis, we similarly create tooling clearing axes for x and y using the bisecting line option in the line command.

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, the proper value (3deg) should be inserted.

FOR CLASS-B SURFACE:
We can divide the surfaces as shown below. Then we will work on them one by one.

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 it with the second rib too.

Following completion of this task, the surface must be trimmed to get the precise shape of the class-A surface (without fillet) below 2.5mm. After the model has been trimmed, fillet it. Filleting formula: fillet value + thickness (if the surface is below). Our class-B surface is delivered.

FOR CLASS-C SURFACE:
1. Extract the boundary of the class-A surface.

2. Extract the boundary of the holes on the class-A surface.

3. Use the sweep command on the boundaries one by one to get the class-C surface.

FINAL BASE BRACKET:
1. Join the class-A and class-C surfaces together.

2. Trim the class-B surface with the join created earlier.

3. Go to part design and close the model.

TREE STRUCTURE:

Screenshots of Complete Draft Analysis:

• Class – A Surface

• Final Plastic Product

Screenshots of color scale variant:

• Class – A Surface

• Final Plastic Product

Screenshots of the solid model with the proper color code of the draft angle in various orientations:

• Isometric View

• Front View

• Side View

• Top View