DEVELOPEMET OF DOOR TRIM PANEL  

AIM: To develop a door trim panel following the design guidelines.

Abstract:

The project report deals with the steps and procedures followed while developing plastic trims for cars door from a class A surface provided, using CATIA V5 surface workbench. It explains the method I followed for creating the main tooling axis, side core axes, Class B surface, Class C surface, and final closed body creations. It also explains the draft analysis performed to check the manufacturability of the products using injection moulding. Various plastic door trims such as map pockets, armrest, a lower substrate, etc were successfully developed in this project.

Problem Statement:

• Create a closed body of the door trim panel using the Class A surface provided along with the master section.
• Create a push pin with the dog house for the lower substrate.
• Use Heat Stakes for the part to the part attachment.

Class A Surface:

In the Automotive industry, there will be a dedicated team who will perform the aesthetic designing of various components including the whole vehicle. They will create various concept sketches after ideation. After that, they will also create a Class A surface of the product. This class A surface is then passed over to the NPD CAD team. They will initially inspect the Class A surface in order to check if the design is manufacturable or if it is following the engineering principles. If there are any issues with the design, they will contact the product design team and will ask to modify the Class A surface in order to solve the problem. Here I received the Class-A surface as shown below.

Map Pocket ;

Arm Rest: 

Lower Substrate:

Map Pocket Lower:

                                                                                   Master Sections:

These are the guidelines provided to a design engineer which describe how a component would/must look like once it is modeled into a solid component from the class-A surface. For example, in this model, we have received a master-section as an input which tells us about the thickness of the component and dimensions & type of the engineering features on the component.

The Sequence of Operation:

1. Creation of Tooling Axis and Draft analysis for A-surface.
2. Creating B&C surface and Draft Analysis 
3. Creating attachment feature on B-Side and Draft Analysis.

Procedure:

Tooling Axis creation   Draft Analysis

The main tooling axis was created by applying a zero distance value on the surface as shown below.

Creating B&C surface for every component;

1.Map Pocket

First Offset the A-surface for 2.5mm(according to master-section) and work on the patches if any are acquired. Fillets were applied after necessary calculations.

Class C surface was swept along the boundary of Class A using the ' Sweep' option at an angle of 3 degrees outwards with respect to tooling direction. In some areas, the 90-degree sweep was applied.

Finally, all the swept surfaces were trimmed and joined together.

The procedure is the same for all components offsetting from A-surface and working on patches if acquired so, and creating C-surface using ‘Sweep’ option at an angle of 3 degrees outwards with respect to tooling direction. In some areas, the 90-degree sweep was applied

2.Map Pocket Lower Part:

 3.ARM REST ;

4.Lower Substrate:

CREATION OF ATTECHMENT FEATURES ON B-SID:

DESIGN RULES FOR DOGHOUSE:

DESIGN RULES FOR RIBS

1. Draft: 0.5 deg per side (minimum), but this value should not be high enough that it will cause failure for other considerations. For example, more draft will result in less thickness at the top surface.
2. The thickness of ribs: 40% of wall thickness or 0.4*t where t is the wall thickness.
3. Height: ≤ 5 times the wall thickness i.e. 5*t.
4. Spacing (for more than 1 rib): 3:1- steel height/width ratio (maximum). h/w =3or2(preferred) where h is the height of the rib and ‘W’ is the space between two ribs.
5. Minimum thickness at the tip: 0.75
6. Radius: 0.25mm max.
7. Ribs on the opposite side of the wall should be offset.
8. Ribs should be connected to other structural features where possible.
9. Rib root thickness should not be more than 30% of the wall thickness.

Creation of Flanges:

Flanges are created wherever required. Master sections are given so that the measurements are acquired and created as shown below.

DESIGN RULES FOR SCREW BOSS :

 Draft - 0.5 degrees on walls of boss
2. Thickness - Typically 60% of the nominal wall at the base.
3. Height to Diameter Ratio - 3:1
4. Radii - 0.25mm maximum radii.

Thus following all the above guidelines screw boss was created.

DRAFT ANALYSIS FOR PLASTIC COMPONENT :

TREE STRUCTURE :  

DRAFT ANALYSIS ;

PUBLICATIONS ;

FINALCOMPONENT

 CONCLUSION :- 

From this project I have leraned how to create CAD model for plastics parts by considering design rule. By doing this project on Catia V5 , I get very well familiar with part workbench ,surface workbench , Assembly workbench. Also I get confidence in handling different features of all workbenches. Along with this , I get idea of how to design a part by considering manufacturing and assembly aspect.