Week 8 - Challenge 5 - Core & Cavity Design

AIM: Design a core and cavity for the switch bezel.

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. Generally, an injection mould has two major components, They are the movable halves and the fixed halve, during the injection moulding 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 parting surface, usually parting surface is the biggest projection outline of the part. Parting surface design directly affects the product quality, ease of construction and operation of the injection mould, the mould design is one of the key factors to success.

PARTING SURFACE:

The parting surface of a mould is 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 various factors to be considered while selecting the parting surface are the Shape of the Components, Type of Mould, Method of Ejection, Method of Manufacture, Location and Type of Gate, and Aesthetics of moulding. In general, the parting surface is classified into two types, they are Flat parting surface, Non-flat parting surface.

DESIGN OF CORE AND CAVITY FOR SWITCH BEZEL:

• 1st create the parting surface for the CATPART, core part and later cavity part.
• Take the A surface and extrapolate the A surface using extrapolate tool and boundary tool.

• Now take the C surface and trim the C surface from the A surface.
• Now take the B surface and trim from the trimmed surface of AC surfaces. This is our parting surface.

• Now designing the core part, by selecting a plane go to the exit workbench and take a rectangle drawn on the switch bezel where the part is located inside the rectangle concerning the tooling axis.
• Now extrude the rectangle and trim it from the parting surface and fill the other side opening of the extruded part.

• Join the fill the trim part. now go to part design from generative shape design and create the solid part of the core with the help of the close surface.

• Take the intersection of the core and the parting surface with the help of the intersection tool.
• Extrude the rectangle which is used to create the core part along the axis and trim the top section of the extrude to the parting surface.

• Repeat the same process similar to the core up to the close surface

• Create an intersection of the core cavity and the parting surface.

• Now by using the translation tool divide the core, parting surface, and the cavity.

Draft Analysis

• The part created has to be changed to the material mode in the display frame
• Then by enabling compass definition the axis system in pan along the direction of the part and aligned in line with the tooling direction Lock Direction is applied that fixes the compass and then the mode dialogue box is formed by snapping at any point on the part
• The Colour Codes are classified and Draft Angle are applied Then the Running point analysis is used to hover around the part to analyse the permissible draft angles and the analysis is saved

TREE STRUCTURE

FRONT VIEW

TOP VIEW

SIDE VIEW

ISOMETRIC VIEW