Week 8 - Challenge 5 - Core & Cavity Design

CORE AND CAVITY DESIGN

AIM:

Creating the core and cavity blocks for the switch bezel design.

PROCEDURE FOR CREATING CORE:

• Extract boundary from class-A surface.
• Extrapolate the boundary.
• Unhide the C surface.
• Trim extrapolated surface with C surface.
• Unhide class B surface.
• Trim the last trim with class B surface.This will be called a parting surface with the component area.
• Sketch a rectangle inside the surface and it will be the dimension for the core.
• Extrude the sketch from both directions.
• Trim the extrude with the parting surface with the component area surface.
• Fill the remaining boundary with the fill surface option and join it.
• Switch to part design workbench,define part body to make core C surface into a solid component by the close surface panel.

PROCEDURE FOR CREATING CAVITY:

• Unhide class B surface and rectangular extrude.
• Trim class B surface and rectangular extrude from below to make it cavity.
• Fill the remaining boundary with the fill surface option and join it.
• Switch to part design workbench,define part body to make core C surface into a solid component by the close surface panel.
• It can also be created in another method:We can pad up the sketch and we can trim core and cavity parts in different bodies.Take a look at the below images,they are self-explanatory.The core has been formed with some translation.Similarly cavity.

THEORY:

• We can see the sectional view of the core and cavity which has the void area where melted plastic will be filled.
• Intersection view of ZX plane with core,cavity,component and parting surface.
• To get a parting line we can intersect the C surface with the B surface.

CORE:

• The core is the male part that forms the internal shape of molding,the upper half of the mold where the tool where the plastic part is injected from is called core.

CAVITY:

• The cavity is the female part that forms the external shape of the molding.

PARTING LINES:

• The parting line of a die-cast component represents where the two different sides of the mold come together.This line often marks the border between the inside and outside the part.
• The location of the parting line indicates which side of the die is the cover and which is considered the ejector.

PARTING SURFACE:

• A parting surface is a surface in the model that you designate to split a workpiece,die block,or another volume.
• It is designed for the removal of the plastic product and the cold slug,the parting surface is where the core meets the cavity and is usually located at the largest section of a product.
  
  

TOOLING AXIS:

• The definition tab on the tool axis dialog control how you want the tool to orient itself whilst cutting a multi axis tool path.
• Tool axis-select to define the tool orientation.The default value is vertical which is used for standard 3-axis machining.However,it can also be a fixed angle or a continuously changing orientation.

DRAFT ANALYSIS:

• The draft analysis command enables you to detect if the part you drafted will be easily removed.This type of analysis is performed based on colour range identifying zones on the analysed element where the deviation from the draft direction at any point,corresponds to speccified values.
• After draft analysis done we can observe that the green colour shows that the drafted walls of the switch bezel are above 2.9 degrees which is a permissible criteria to manufacture in injection moulding.

CONCLUSION:

• The design of core and cavity is thus done.

TREE STRUCTURE:

ISOMETRIC:

FRONT:

TOP: