Week 8 - Challenge 2 - Switch Bezel Design

Switch Bezel Design

AIM:

This project aims to create a switch bezel plastic component using the given class A surface following the OEM standard. and perform the draft analysis.

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 OEM’s, hence by considering the manufacturing consideration the switch bezel is designed.

CLASS-A SURFACE: the class-A surface is used in the automotive design industry. it the describes the final production surface data for the aesthetic parts of the car.

CLASS-B SURFACE: The Class B finish is a quality finish with only minimal imperfections.

CLASS-C SURFACE: The interior surfaces not readily visible, surfaces that will be covered by another part when assembled, or surfaces which the Customer feels do not need to meet a high cosmetic finish.

Creating tooling axis:

• The ejection from the mold after manufacturing the interior trim must have the nominal 3-degree draft angle.
• hence the tooling directions created by considering the above factor and bisecting method is used.
• The base surface of the class-A was extracted to create a reference point on the surface using the point, create a line in the z-direction and an axis system was inserted to the point
• Tooling direction is the main consideration for plastic part and mould parts because it defines the movement of the mould part and the possibility of the plastic part coming out from the mould part (Core and Cavity).

DRAFTING ANALYSIS:

• Draft analysis is performed on the components where the ejection of materials happens after the material is made inside the tools.
• In the case of automotive sheet design manufacturing, the blank sheet after turning into automotive panels like Hood, Fender, Roof, Side Doors, Back Doors etc. need to be removed from Panel Dies.
• If a considerable amount of draft angle is not provided, the removal of components from the tool will be difficult.
• It’s the same in the case of mold(plastic component) after getting filled inside the core and cavity, it needs to get ejected easily with the help of ejectors.

MATERIAL USED FOR SWITCH BEZEL:

ACRYLONITRILE BUTADIENE STYRENE(ABS):

High Rigidity:

• ABS has high rigidity and impact resistance. Even in low-temperature conditions or over long periods, ABS plastics will retain these characteristics.
• Its tensile strength is around 35-44 Mpa and because of its plastic yield at high strain rates, the impact failure of ABS is ductile rather than brittle.
• It is used in Instrument-Panel, Door-trims, etc. As it has good impact resistance, it is used in creating bumpers as well.

Excellent Insulation:

• It has very good insulating properties, both acoustic and thermal.

Highly Weldable:

• It is a good weldable material as it is an amorphous material
• It is usually measured in terms of stiffness or modulus.

High Dimensional Stability:

• It remains mechanically strong over time.

Good Surface Characteristics:

• High Surface brightness and excellent surface finish. ABS is an ideal material whenever superlative surface quality, color fastness, and luster are required. ABS is a two-phase polymer blend.
• A continuous phase of ‘Styrene-Acrylonitrile’ co-polymer(SAN) gives the material rigidity. Hardness and heat resistance. The toughness of ABS is the result of microscopically fine polybutadiene rubber particles uniformly distributed in the SAN matrix.
• Hence, ABS is also used in Wheel-covers, IP substrate, etc

Good Abrasion & Strain Resistance

CLASS-A:

• NO changes made in class-A.
• Considering the Ejection from the cavity of the mould after manufacturing the interior trim (switch bezel) must have the 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.

CLASS-B:

• 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 have been 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

CLASS-B EXTRACT:

CLASS-B UNTRIM &OFFSET:

CLASS B FINAL:

CLASS-C:

• The edges of the Class-A surface are extracted using the multiple extracts and then converted into smooth curvature to avoid the patches.
• Now this smooth curve is swept along the draft direction with a 3deg draft.
• join class-A and class-C surfaces. Make sure that there is no unnecessary boundary present, if there is then increase the merging distance to not more than 0.003mm. and even after there is some unwanted boundary, extrapolate class-A by a small distance and trim it with class-c instead of joining them.

CLASS-C BOUNDARY:

CLASS-C SMOOTH CURVES:

CLASS-C SWEEP:

CLASS A & C:

CLASS A-B-C:

CLASS A-B-C DRAFT ANALYSIS:

FINAL SOLID PART:

TREE STRUCTURE:

CONCLUSION:

Switch Bezel plastic component using class-A surface successfully created and performed the draft analysis on the class-A surface and final plastic component.