Week 8 - Challenge 2 - Switch Bezel Design

Design and Draft analysis of Switch Bezel design using CATIA v5

Aim:

The objective of the project is to design the switch bezel and to do a draft analysis for it by creating the required tooling direction with the help of Bisecting method.

Introduction:

The control panel bezel is the frame part of the window switch that holds its switch covers and buttons into place. Moulding is the method used to manufacture the plastic trims of an automotive by most OEMs, hence by considering the manufacturing consideration the switch bezel is designed.

Design Consideration:

• Class – A surface should be aesthetically smooth and good.
• Class – B surface should have all the supporting features like ribs.
• The parting Line should coincide with the B surface since flashing couldn’t affect the aesthetic of Class – A.
• Class – C surface should also pass the draft analysis.

Procedure of creating Switch bezel:

• First, the given styling surface is checked for any irregularities and if found then it is corrected by using Trim, Extrapolate, Split and Join commands.
• The below image shows that the Class–A surface is clean and no irregularities present, so let's move on to the next step.

Creation of Tooling direction:

• Considering the Ejection from the cavity of the mould after manufacturing the interior trim (switch bezel) must have a nominal 3-degree draft angle.
• Hence the tooling direction is created by considering the above factor and bisecting method is used.
• The base surface of the class – A was extracted and a point at the centre is created and an axis system was inserted to the point with the current feature is disabled.
• Then, using project intersection along yz plane is created and the two inclined lines were drawn inside the positioned sketch.
• Then bisecting lines with the two inclined lines were drawn.
• Now the same procedure is done along the xz plane but on one side we don’t have inclined lines so the centre point is used to extrude a line along the z-direction and gave a measurement of 5 degrees (Tentatively).
• With these two lines from sketches 1 and 2, the bisecting line is crated and published as Tooling Axis(tooling direction).

Creation of Class-B surface:

• For creating the class-B surface the required surface except the offset surface have been extracted and then untrimmed all the surface.
• Then all the surfaces were extrapolated to get intersections between them.
• Since the thickness of the Switch bezel is 2.5mm the B-Surface was offset to 2.5 mm and the required trim operations must be carried out.
• Finally, the required corners have been filleted to 12.5mm (15mm-2.5mm). [ 15mm - fillet value of the A-surface, 2.5mm – Thickness of the component ]

Creation of Class-C surface:

• The required outer edges of the A-Surface were extracted using Multiple Extract. Then for avoiding the patches the curve is smoothened using the Curve Smooth option.
• Then by using the sweep command the surface was created with the following feature controls,

1. Profile type – Line
2. Subtype – With Draft Direction
3. Guide Curve – Smooth Curve
4. Draft Direction – Tooling Axis
5. Draft Computation Mode – Square
6. Angle – 3 Degree
7. Angle Sector – Positive Downward (1)
8. Length – 20mm

• Then by using extrapolate command the edges were intersected between the surface corners which eases the trimming operation.
• Now the required portion of the C – surface were trimmed out.

Creation of closed surface:

• Now the class – A and Class- C surfaces were joined together by removing the gaps in between them with the help of extrapolation(tangent continuity) and Trim surface.
• Then the exact surface of the Switch bezel was trimmed from the above-resulted trim surface with the class-B surface.
• Then, by defining the part body by using the Closed Surface command in Part Design, the component's solid body is created.

Procedure for draft analysis:

• First the class – A surface is checked before creating the Class –B&C surface and finally the solid body must be analysed. Both can be done by following the below procedures.
• By changing the view mode to custom view parameters – Material mode, the feature draft analysis is enabled.
• Then the compass was activated and placed with the tooling axis by dragging the red pointer and then locking it.
• Then, by selecting the quick analysis mode, the nominal value will be 3 degrees and checked for the component's draft angle.
• The green colour area shows that it satisfies the 3-degree draft angle. If not satisfied then by using the Running point tool the area is measured and then altered to get a successful draft for the created tooling direction.

Conclusion:

Finally the Class – A, B&C surfaces with the Tooling Direction have been Published and the Switch Bezel is moved on to the designing of the next operation – the creation of B-side features.