Week 8 - Challenge 6 - Core & Cavity Design

AIM: To create the core and cavity for the switch bezel considering all design rules.

The core is the part that forms the internal shape of the molding. The cavity is the part that forms the external shape of the molding. The core is the side of the tool where the plastic part is injected from; also known as the bottom half of the tool. The upper half of the mold is called CORE. A tool with one impression is often called a single impression (cavity) mold. A mold with two or more cavities of the same parts is usually called a multiple impression (cavity) molds.

CORE AND CAVITY design for switch bezel:

first of all, you have full knowledge about what is, cavity, parting surface, parting line, etc.

Core and Cavity:

A core is the one part of the mold. and it is responsible for half of the molded part. the core is the projection of the body and the cavity is the depression of the body. these core and cavity combine to form a mold. then the plastic material is injected into this mold to get a plastic part.

Parting surface:

Injection mold has two major components one is the core and another cavity .during the injection molding process, these two halves are pressed tightly from a sealed hollow to avoid the melt flow leakage and maintain certain holding pressure, the pressed surface is called the parting surface, usually parting surface is the biggest projection outline of the part.

Parting line:

It is the area in which the parting surface and component meet Or it is a junction between core and cavity and the parting surface has some set of rules because the product quality mostly depends on the parting surface.

DESIGN PARTING SURFACE SHOULD FOLLOW THE FOLLOWING PRINCIPLES :

1. Design the injection mold simple as possible. Avoid or reduce side parting as much as possible to reduce the complexity of mold making.
2. Ease of de-molding as far as possible, for instance, the plastic parts should stay in a fixed halve of the injection mold and should be ejected by the ejection system to avoid, side de-molding action,
3. Ensure the dimension accuracy of the molded parts, Try to make the parts similar to dimension accuracy requirements in the same mold to reduce manufacturing and assembly errors.
4. Ensure the apperance requirement of molded parts, finish or mismatch usually occurs on the parting surface, so the parting surface should not be designed on high-quality requirement surfaces.
5. Ensure adequate venting. If possible parting surface should be placed at the end of the mold flow. This is going to be the advantage of filling and venting.

Core design:

1. To extrapolate class A surface
2. trim class A with class c to get an inside portion
3. Now, trim the B surface with an output of Class A & C that will be parting surfaces concerning the area. Extrude the sketch overall through the tooling direction are trim it with a parting surface.

Similarly, Repeating the same as done for the cavity part and trimming it on the other side surface.

Feature Tree

The core and cavity blocks in various orientations

Result:

The core and cavity for the switch bezel have been created as per the design rules.