Week 8 - Challenge 6 - Core & Cavity Design

The halves of the mold work like this:

Core (B Side): The core is usually the interior or noncosmetic side of the part. The core side also contains the ejection mechanism that pushes the completed part out of the mold.

Cavity (A Side): The cavity is the void inside the mold that the molten plastic fills. Plastic enters the mold from the cavity side and forms the final shape of the part. The cavity side usually forms the cosmetic side of the part.

Core & Cavity:

• The 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.
• Core is an extended or male portion of the mould which creates the internal plastic part surface
• Cavity is a depression or female portion of the mould which creates the external plastic part surface.

TOOLING AXIS:

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.
• 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.

PARTING SURFACE

Generally injection mold has two major components : the movable half and the fixed half, during the injecction 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 are called parting surface , usually parting surface are the biggest projection outline of the part.

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.

PARTING LINE

• A parting line is an inevitable part of injection molded products.
• It is the line of separation between where two halves of a mold meet.
• It manifests itself on injection molded parts as a line that runs the entire perimeter of the part.
• In most parts, it is just a line that runs straight down the middle.

INTERSECTIONS

DYNAMIC SECTION:

DRAFTING:

TREE STRUCTURE:

VIEWS:

Challenge 6 - Core & Cavity Design