Week 8 - Challenge 6 - Core & Cavity Design

CORE & CAVITY DESIGN - SWITCH BEZEL:

AIM: To create the Core and Cavity Blocks for the designed Switch Bezel component.

GIVEN CLASS A SURFACE:

The Class A Surface is quality checked for any open profiles in the geometry using the 'Boundary' command. If there are any open profiles found in the Class A, they are joined using the 'Join' command with a merging distance of maximum 0.003 mm.

REPORT ON TOOLING AXIS CREATION AND DRAFT ANALYSIS:

TOOLING AXIS CREATION:

Tooling axis is the direction the mold pulls apart. It is necessary to create a tooling axis to provide draft to the component. Tooling axis can be created using the "Bisecting Method". To create a tooling axis, the Class A surface is observed in all directions and the best tooling direction for the component is chosen by considering the tooling of the final product. It is chosen in such a way that the component is cleared with minimum tooling.

BISECTING METHOD:

In this case, it is found that the given component is clearing the tooling in Z direction. On the Class A, a point is created at the geometric centre of the base using the "surface type" in point definition. An axis system is then created with the point as origin. It is made sure that the axis system is not current one.

Then a bisecting line for the two opposite walls is created in YZ plane by intersecting the 3D elements in the positioned sketch. 

Since there is no opposite wall for the other vertical wall, a line is created using positioned sketch in the XZ plane with an angle to the intersection line of the 3D element with the origin as starting point. The angle is taken as 6 degrees which can be obtained by trial and error after draft analysis on Class A.

Now an other line bisecting the first two lines is created using the 'Bisecting Type' in life definition. The inputs given for this bisecting line are the two previous sketches and the center point. This line thus obtained is the main Tooling Axis of the component.

It is renamed as Tooling Axis and is then published for easy accesibility. This is the process of creating a Tooling Axis using the Bisecting Method.

DRAFT ANALYSIS :

Draft is the degree of taper that is incorporated into the side walls and cores of the die cast tool to aid in the removal of a part. Primarily, they function to reduce the friction between the part and the tool as it is ejected. Without draft angles, parts can be stripped, dented, or get stuck in the tool.

Draft Analysis enables you to detect if the part you drafted will be easily removed. In the case of plastic injection molded parts it also allows the designer to see if there is enough draft on the part to ensure that it can be correctly grained.

DRAFT ANALYSIS ON CLASS-A SURFACE:

Draft Analysis is performed on the Class A Surface using the Draft Analysis command in CATIA after creating the Tooling axis. It is performed to check if the surface clears the tooling. The compass is used to define the current draft direction. It is aligned with the Tooling Axis to define the draft direction and the surface is selected to perform the analysis.

From this analysis, it is clear that a minimum draft of 3 degree is maintained for the Class A surface as the colour 'green' indicates that the surface passed the draft check which can be seen from the colour scale table. The second picture shows the Full Draft Analysis of the surface with the color scale table.

Thus we can conclude that the Class A Surface clears the minimum required draft angle.

DRAFT ANALYSIS ON SOLID MODEL:

Draft Analysis is also performed on the final Solid Model to check if the B and C surfaces clear tooling. Procedure similar to that of the analysis performed on Class A surface is followed here.

From the analysis, the C surface of the part body can be seen clearing the tooling for a minimum of 2.9 degrees of draft. Whereas when the clearing check is increased to 3 degrees, the surface do not clear due to deviation. So, a draft check of 2.9 degrees is feasible.

DRAFT ANALYSIS ON SOLID MODEL IN VARIOUS ORIENTATIONS:

CORE AND CAVITY BLOCKS:

CORE AND CAVITY BLOCKS IN VARIOUS ORIENTATIONS:

CORE BLOCK:

CAVITY BLOCK:

CORE & CAVITY: