Week 12- Final project

Aim:
To design and develop the door trim panel components, including the lower substrate, armrest, bottle holder, and map pocket, using the provided input Class A surfaces. The project involves creating Class B and C surfaces, generating solid bodies, and incorporating necessary B-side features (heat stakes, 4-way locators, doghouses, push clips, ribs, screw bosses, etc.). The components are assembled into the final door trim panel with proper constraints, and draft analysis is performed using CATIA V5 to ensure manufacturability.

Objective:
The objective is to achieve:

• A fully manufacturable door trim design by creating Class A, B, and C surfaces and solid bodies.
• Draft analysis for Class A surfaces with a minimum draft angle of 3 degrees and B-side features with a draft angle of 0.5 degrees.
• Development of structurally sound and functional B-side features as per industry standards.
• Assembly of components into the final door trim panel with proper constraints.

Procedure and Additional Findings

1. Input Surface Analysis:
   Analyze the Class A surface to assess curvature continuity (G0, G1, and G2 continuity checks) and identify areas requiring additional attention to avoid design defects such as undercuts or sharp edges.

2. Tooling Axis Creation:
   The bisection method ensures that the tooling axis aligns with the optimal direction for mold ejection, minimizing manufacturing challenges like material warping or incomplete ejection.

   Additional Findings:

   • Multi-directional tooling may be necessary for complex features such as undercuts in bottle holders or map pockets.
   • Tool clearance must consider draft angles, wall thickness, and rib depth to avoid deformation during ejection.

3. Draft Analysis for Class A Surface:
   Conduct an initial draft analysis to validate that the design meets the required draft angle.

   Additional Findings:

   • Areas with insufficient draft (less than 3 degrees) can lead to surface defects or require secondary machining operations, increasing costs.
   • Optimization of Class A surfaces at this stage reduces the likelihood of rework in later stages.

4. Class B Surface Creation:
   The Class B surface incorporates all engineering features.

   Additional Findings:

   • Uniform wall thickness (avoiding thickness variation) is crucial to prevent sink marks and warping.
   • Ribs should follow a height-to-thickness ratio of 3:1 to 5:1 for effective strengthening without increasing weight.
   • Placement of heat stakes and screw bosses should ensure proper load distribution to prevent failure under stress.

5. Class C Surface Creation:
   The Class C surface provides the necessary thickness to complete the component.

   Additional Findings:

   • Ensure that the Class C surface maintains tangential continuity with Class A and B to prevent visual defects on the final product.

6. Solid Body Generation:
   Combine Class A, B, and C surfaces into a single solid body, ensuring that all surfaces align and intersect properly.

7. B-Side Features Creation:
   Add necessary B-side features based on the master sections provided.

   Additional Findings:

   • Doghouses: Keep doghouse depth around 40-60% of the wall thickness to maintain structural integrity without adding significant weight.
   • Heat Stakes: Avoid sharp edges on heat stakes to ensure proper melting during assembly.

8. Draft Analysis of Solid Body:
   Perform draft analysis to validate that all features comply with tooling requirements.

   Additional Findings:

   • Areas around screw bosses and ribs often fail draft analysis due to tight angles. Smooth transitions and fillets can resolve these issues.

9. Assembly of Components:
   Assemble all components in the assembly workbench of CATIA V5 using appropriate constraints such as offset, coincident, and contact constraints.

Key Findings

1. Design Optimization for Manufacturing:

   • Proper placement and sizing of ribs, screw bosses, and heat stakes prevent defects such as warping, sink marks, or part failure under stress.
   • Undercuts in areas like bottle holders may require the use of sliding cores or side actions in molds, which can increase tooling complexity and cost.

2. Draft Angle Significance:

   • A minimum draft angle of 3 degrees on Class A and solid surfaces ensures ease of ejection, reducing the risk of scratches or material deformation.
   • B-side features, with their tighter draft angle requirements (0.5 degrees), must be thoroughly analyzed to ensure manufacturability without compromising functionality.

3. Material Considerations:

   • The choice of plastic material plays a significant role in the design process. High-strength materials may allow for reduced wall thickness, while softer materials require additional reinforcements.
   • Thermal expansion and shrinkage must be accounted for during tooling design to maintain dimensional accuracy.

4. Draft Analysis Iterations:

   • Performing draft analysis at each stage of the design (Class A, Class B, and solid body stages) ensures that potential issues are caught early, avoiding costly rework.

5. Assembly Constraints:

   • Proper constraints ensure the stability of the assembled components and allow for easy modifications if design changes are needed.