Week 9 - Project 1 - Door Trim Lower with Engineering Features

Title: Door Trim Lower with Engineering features Using CATIA V5

Objective: To create the Door Trim Lower Plastic component with Engineering Features through the given Class-A surface. As well as, creating the tooling axis for the given Class-A Surface which is meeting the requirements of the draft angle and at the end perform the Draft analysis on the model.

Introduction:

Heat staking also known as thermoplastic staking is the process of joining two dissimilar materials together. In heat staking we use local heating and cooling to raise the temperature of plastic components and allow plastic reforming to be carried out. This reforming can be used in a wide variety of applications.

Locators are features which are used to arrest the degrees of freedom while the components are being assembled.

Specifications:

Door Trim Thickness = 2.5 mm

Minimum Draft Angle = 3 Degrees

Definitions:

1. Class-A Surface: it is a surface created by the styling team which is then given as an input to the plastic designer to create the plastic component. It is the aesthetic surface and the outer most surface.
2. Class-B Surface: it is the surface below a certain thickness from the Class-A surface created by the plastic designer. This surface contains all the engineering aspects of a model.
3. Class-C Surface: it is the surface which joins the Class-A and Class-B surfaces together.
4. Draft: it is the amount of taper or slope given to cores or other parts of the die cavity to permit easy ejection of the casting from the die casting die.
5. B-Side Features: this are the engineering features or supports attached to the Class B surface of a given plastic component.

Design Methodology:

Class A Given

1. Tooling Axis: for creation of the tooling axis, we follow the normal to surface line method.

1. First, ensure that the Class-A surface is properly joined and has no discontinuity. Select the boundary command from the toolbars and then select the Class-A surface. A boundary should only appear on the outer edges of the component.
2. Then, we decide the proper tooling axis direction with respect to the given component (in this case it is the Z-axis direction).
3. Generally, the tooling axis is created using bisecting lines method. But in this model, we observe that the side walls are not given any draft. Hence, we assume the axis normal to the base surface and parallel to side walls.
4. We create a line normal to base surface by creating a point first on that surface and then create the line using the Normal to Surface method and taking the base surface and the point as references. This new line is considered as the tooling axis.
   
   
   Tooling Axis

2. Draft Analysis: to check whether our tooling axis is proper or not we do the draft analysis.

1. Go to insert > analysis > feature draft analysis.
2. Align the compass with the tooling axis.
3. Then, click on the Class-A surface to see if the it is within the permissible limit of the draft values.
4. The Class-A surface should turn green and then draft value should be given as 3 degrees.
   
   
   Draft Analysis

3. Class-B: we create the Class-B surface by extruding the Class-A surface by 2.5 mm

1. First, we will use the Extract the total Class A surface by Offsetting it to a distance of 3 degrees.
2. After that, we see that some surfaces could not be extracted properly, thus leaving some small patches which we need to fix by using some surface creation tools like Multi-Sections Surface, Blends and Sweep.
3. After, closing all the small patches we use the Join command to ensure that the surface is properly joined.
   
   
   Class B

4. Class-C: we create the Class-C surface by extruding the edge boundaries of the Class-A surface by 2.5 mm.

1. First, we extract the outer boundary of the Class-A surface separately.
2. Then, we sweep this boundary using the sweep command. We select the Line option on the sweep command menu, the extracted boundaries as Guide curve 1 and the Class b surface as the Guide Surface. Also, we specify the draft angle as 90 degrees. We give this value because the Class C surface is perpendicular to the Tooling Axis direction.
3. After that, we join all the Class-C surface with the Class-B surface by using the Trim command.
4. Lastly, we use the Join command to join the Class A, B and C surfaces together and obtain the proper desired surface.
   
5. 
   
   Class C

5. Part Body: we create the final solid body using the Closed Surface command.

1. Go to Boundary command and click on the new surface. An error dialog-box should pop-up.
2. Go to the Part Design workbench.
3. Select the Closed Boundary option and then click on the generated surface.
4. A closed solid body is obtained.
   
5. 
   
   Part Body

DRAFT ANALYSIS

6. Attachment Features: we add these features to the part body by using Boolean operations.

1. Heat Stakes: for the heat stakes we draw two concentric circles, thick pad them and then create the side rib support using thick pad command as well. We give a Draft of 0.5 to the main body.
   
   
   
   
2. 

1. Locators: for the locators we draw lines and thick pad them. We give a Draft of 0.5 to the main body.
   
   
   
   

CREATING THE RIB

Ribs are thin wall protrusions that extend perpendicularly from a wall or plane. They are usually found in clusters offering support to a plane that would have otherwise been too thick, but can also be stand-alone support for a single wall. They are commonly used to provide additional support and strength to a part. Thickness and location are essential to rib design.

First, the base surface where the rib has to be created is extracted using the Extract command.

CREATING THE DOGHOUSE

The dog house is an engineering feature used in the plastic trim design. Dog houses are used as a supporting feature. Sometimes other engineering features like snaps; locators, etc. are mounded on them to increase their strength.

final solid body:

DRAFT ANALYSIS