Week 8 - Challenge 6 - Core & Cavity Design

A DETAILED REPORT OF CORE AND CAVITY DESIGN

TITLE: Switch Bezel Design(CORE AND CAVITY) Using CATIA V5(CHALLANGE-6)

First create the palstic component From Class A to Class B and Class c

after that create core and cavity with parting line and parting surface.

Objective: To create the Switch Bezel Plastic component 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,and after that create the core and cavity with parting line and parting surface.

Introduction: The switch bezel design in automobiles is the frame part of the window switch that holds its switch covers and buttons into place.

Specifications:

Switch Bezel Thickness = 2.5mm

Minimum Draft Angle = 3 Degrees

Definitions:

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.Class 'A' surfaces are primarily used in the automotive environment and refer to those surfaces which are visible in a product.

Class-B Surface: it is the surface below a certain thickness from the Class-A surface The Class B finish is a quality finish with only minimal imperfections.

A Class B finish is the most common finish for exterior surfaces. It is normally specified on surfaces such as external covers, panels, and parts that are fairly prominent created by the plastic designer. This surface contains all the engineering aspects of a model.

Class-C Surface: it is the surface which joins the Class-A and Class-B surfaces together.

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.

Core and cavity

1. Creation of THE PARTING SURFACE

2. Creation the CORE BODY

3. Creation the CAVITY BODY

4 Creation the PARTING LINE.

PARTING LINE----Parting line is the intersection between the parting surface and the component.

the side which has projection will be used core and other as a cavity.

parting surface for the core can be created by Trimming class A and class C surfaces with class B as shown.

Design Methodology:

CLASS A SURFACE

1. Tooling Axis: for creation of the tooling axis, we follow the bisecting lines 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. After that, we create a point and an axis system on the Class-A surface and then create two sketches on the zy and zx planes respectively.
4. In the first sketch on the zy plane, we will draw two inclined lines coinciding with the intersection curve of the Class-A surface along the y-axis direction. Then we will create a bisecting line with these two lines.
   
   Sketch 1
   
   
5. For the sketch on the zx plane, the same procedure is done but on one side we don’t have inclined lines so the center point is used to extrude a line along the z-direction and gave a measurement of 3 degrees (tentatively).
   Sketch 2
   
   
6. Lastly, we create the tooling axis by creating a bisecting line with the two previous sketches and the point that we created on the Class-A surface.
   
   

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.
   Class-A 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, Un-trim, Extrapolate, Trim and Offset commands on the base surface, the walls and the Bezel rest surface of the Class-A surface separately to create the desired Class-B surface.
2. After that, we will use the Trim command to get our proper desired Class-B surface.
3. We will give proper fillets to the edges of the Class-B surface Class-B Surface

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 edge boundary and inner edge boundary of the Class-A surface separately.
2. Then, we sweep each of these boundaries using the sweep command. We select the Line option on the sweep command menu, the extracted boundaries as Guide curve 1 and the tooling axis as the draft direction. Also, we specify the draft angle as 3 degrees.
3. After that, we join all the Class-C surfaces with the Class-A surface by using the Join command.
4. Lastly, we use the trim command to join the Class A, B and C surfaces together and obtain the proper desired surfa Class-C Surface
   
   
   

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.

FINAL SURFACE

Draft Anaysis of the final solid body:

Since, the draft analysis is not giving us the desired result we must modify the inclination of the tooling axis to increase its inclination angle and thus by some trial and errors we get our desired value.

We change the inclination angle of zx plane line to 4 degrees.

PARTING SURFACE

CORE DESIGN

CAVITY

PARTING LINE

CORE AND CAVITY BLOCK