Week 8 - Challenge 6 - Core & Cavity Design

AIM:

To create a switch bezel from the given A-class surface by considering a thickness of 2.5 mm and also creating Core and Cavity blocks for it.

Final switch bezel component :

TOOLING AXIS:

Tooling axis :

• To create the tooling axis, we need the proper orientation or view that gives the correct features and draft available in the component.
• So here the component view from the Z direction gives the proper view for the tool to see the features present in the geometry.
• To create the tooling axis from the Z direction we need the tooling axis from the other X direction since it gives the draft available at the slanted part.
• The tooling axis created from the X direction by following steps

1. The base surface is extracted.
2. Then the center point is created using the point > on the surface at 0
3. At the point created the axis system is created
4. After that switching the view of the model to the X direction and creating the tooling axis.

Using the intersect in ZY plane to get the boundary lines.

Then the lines are created along the slant surfaces.

Then these two lines are bisected to get the tooling axis for the X or the final

1. Next, switching in the Y direction and intersecting the switch bezel part in ZX direction to get the intersecting lines.
2. Using the axis center point, a line is drawn in sketch mode and it is constrained at the angle of 4 degrees. (this angle value is an arbitrary value and can be changed to get the final tooling axis that provides a positive draft )
3. At last, both the lines are bisected to get the final tooling axis.

Draft analysis :

• The Draft Analysis dialog box is displayed. It gives information on the display (color scale), the draft direction, and the direction values.

• The Draft Analysis.1 dialog box showing the color scale and identifying the maximum and minimum values for the analysis is displayed too.

CORE AND CAVITY DESIGN:
The Mould Core & Cavity are the shaped sections in either half of the mould tool which give the plastic product its final shape.

The hot molten material is injected into the core & cavity and then sets hard into shape. The design of the core & cavity is essential in the correct formation of the product. The sequence of events during the injection mould of a plastic part is called the injection molding cycle.

The cycle begins when the mould closes, followed by the injection of the polymer into the mould cavity.

A core is usually made of the best quality sand and is placed into the desired position in the mould cavity. Core prints are added to both sides of the pattern to create impressions that allow the core to be supported and held at both ends.

Core :

• The core design is started with extracting the parting surface that becomes the datum for the core and cavity. The parting surface in most of the cases is kept at the B class surface to avoid close and tight contact between the core and cavity.
• At first, the A-class surface is extrapolated with some length and later it is trimmed with a C surface

This A and C surface again trimmed with the B surface to form the core face.

Parting surface with a component area

Now, the final core block is made by drawing the boundary sketch and extruding it along the tooling axis direction followed by the filling and thickening

CAVITY:

The cavity is the part where the injector and filling of the molten plastic happens. The cavity block is prepared by first extruding the outer boundary along the tooling direction.This outer surface is trimmed with the B class surface and then it is filled and thickened.

Parting line :

A parting line, in the industrial casting of molds, is the borderline in which draft angles change direction. That is, it is the dividing line that splits the core and cavity halves of a molded part. It is sometimes a starting point for the mold parting surface.

Here intersecting the parting surface, core, and cavity across the ZX plane gives the intersecting line that tells the parting line.

Parting surface:

The parting surface of a mould are those surfaces of both mould plates adjacent to the impressions which butt together to form a seal and prevent the loss of plastic material from the impression. The parting surfaces of a mould are those portion of both
mould plates, adjacent to the impressions, which butt together to form a seal and prevent the loss of plastic material from the impression.

FINAL :