Week 8 - Challenge 3 - Switch Bezel Design

SWITCH BEZEL DESIGN

Objective: To design Switch Bezel and perform draft analysis on both the Class A Surface and the final model along the tooling axis meeting the requirements of the draft angle.

Introduction:

Class A Surface:

In automotive design, a class A surface is any of a set of freeform surfaces of high efficiency and quality. Although, strictly, it is nothing more than saying the surfaces have curvature and tangency alignment to ideal aesthetical reflection quality, many people interpret class A surfaces to have G2 (or even G3) curvature continuity to one another.

Class A surfacing is done using computer-aided industrial design applications. Class A surface modellers are also called ‘digital sculptures’ in the industry. Industrial designers develop their design styling through the A surface, the physical surface the end user can feel, touch, see etc.

Class B Surface:

Class B Surface is a surface below a certain thickness from a Class A Surface. We can also say that it is an engineering surface because it contains all the engineering aspects of the model which is required.

Class C Surface:

Class C Surface is a surface that joins the Class A Surface with Class B Surface.

Tooling Axis:

Tooling axis is the direction in which the mold or core and cavity opens.

Draft:

Draft is the angle in which the part is tapered to allow it to release. As the part cools, it tends to shrink to the core side of the mold. Draft is required on all parts in the direction of mold movement in order to allow parts to release or eject from the mold properly.

Most parts or applications require a minimum of 0.5 to 1 degree, however 3 degree is widely accepted as normal.

Draft Analysis:

Draft analysis is done in order to detect if the part that has been drafted will be easily removed or not. This type of analysis is performed based on the colour ranges identifying zones on the analyzed elements where the deviation from the draft direction at any point corresponds to the specified values. When the draft analysis passes, it means our part is easily toolable or can be easily ejected.

Methodology/Approach:

Procedure:

1. Importing Class A Surface:

First of all we have to import the class A Surface into the Catia V5 Software.

2. Continuity Check:

After getting the Class A Surface from the styling team, we have to ensure that the Class a Surface is properly joined and has no discontinuity on it. To check that we have to use the Boundary command or Join command.

3. Creation of Tooling Axis:

First of all we have to analyse manually or visually to see which direction is the most appropriate for tooling axis. After analysing we found that in x directing the pocket and flat surface are creating problems, in Y direction we cannot do because Pockets and the walls are difficult to be tooled and Z direction we found it very easy to be tooled. So, we create the tooling axis using bisecting line method.

X-Direction;

Y-Direction;

Z-Direction;

Bisecting line Method:

We will use x direction and y direction to see if they are clearing a tooling or not. Here we extract the base surface and create a point on the surface extracted and also create an axis system on that point. In Y direction we create a sketch and Intersect the Class A Surface with YZ plane and on the parallel lines we create another coincident lines and then finally create the bisecting line using those lines.

In x direction we found only one parallel face. So, we create another sketch and intersect ZX plane and then we create another line from the axis system 3 degree from the intersection lines earlier created.

After that we again use the bisecting line method to create the bisecting line from the lines we created in X direction and Y direction.

This line is our final tooling axis.

4. Draft Analysis of Class A Surface:

First of all we should change the view to the Customize View parameters and then select the material mode and the ok. After that we will open draft analysis command and then click on the compass icon and then align the compass of the window with the tooling axis earlier created and then lock the draft direction. After that click on the surface and see that the surface is within permissible limit of the draft value. The surface should be green and in the column 3 degree should be inserted but thge middle wall is red so we modified the earlier created angled line from 3 degree to 4 or 5 degree and our draft is ok at 5 degree.

5. Creation of Class B Surface:

First of all we will divide the Bezel rest surface, the walls and the base surfaces and then perform the action one by one.

For Bezel Rest Surface;

• Extract the flat surface and not the filleted surface

• Untrim them

• Extrapolate them

• Offset the surface by 2.5 mm downward

For Walls;

• Extract the slanted surface

• Untrim them

• Extrapolate them

• Trim them

• Offset the surface by 2.5 mm outward

For Base;

• Extract the surface

• Untrim them

• Extrapolate them

• Offset the surface by 2.5 mm downward

After that we will trim the bezel rest surface with the walls and then with the base surface. Then we will add the fillet value considering the equal wall thickness of the component. This is our final Class B Surface.

Checking fillet value of class A Surface;

6. Creation of Class C Surface:

For class C Surface we have to extract the outer boundary in two halves using multiple extract option.

After that we will sweep the both boundary one by one in downward direction and draft to be outward.

We found that at two points the surface are not joined so we extrapolate them and then trim them.

But there are number of patches on the surface so we use smooth curve and the replace them with the extract created earlier to have smooth surface. This is our final Class C Surface.

7. Solid Body Formation:

Join the class C surface with class A surface.

So, we increase the merging distance of join value to 0.003 mm.

Trim the B surface with the join created earlier.

But we found some boundaries after checking over the model so we join the model by merging distance of 0.1 mm because there is a problem in the Class A Surface itself. Now the model has no any extra boundaries.

Go to the part workbench and close the part using close surface option.

8. Final Draft Analysis:

First of all, change the view to Customize View Parameters and then check material mode selected and perform the same operation as done for Class A Surface while we did in doing draft analysis.

3D View of Final Model:

Isometric View:

Front View:

Side View:

Top View:

Tree Structure:

Conclusion:

From the given Class A Surface of the Switch Bezel, Class B Surface and Class C Surface were created to form a solid model and Draft analysis was done for both Class A Surface and the 3d model along with the tooling axis meeting the requirement of draft angle.