Week 8 - Challenge 6 - Core & Cavity Design

SWITCH BEZEL CORE AND CAVITY DESIGN
This report demonstrates the complete design of an Automotive Plastic Component – Switch Bezel from a given Class-A surface as an input.

Note:

• 
  Thickness of the component is 2.5 mm.
• The component is designed using CATIA P3 V5-6R2021

OBJECTIVE

The aim of this Project is to create the Plastic component SWITCH BEZEL from Class-A surface along with creation of TOOLING AXIS. In the end DRAFT ANALYSIS of class-A along with the closed body has also been performed.

INTRODUCTION

TOOLING AXIS:
The line along which the mold (CORE and CAVITY) opens. It decides the direction of two mold half opening or closing. The component should clear the tooling axis in the given specific direction. As a general rule, along tooling axis we must we able to see maximum faces of the component.
There are different methods to create tooling axis. It depends

• According to the given surface geometry (face symmetry, surface normal, assembly
  direction etc)
• Already given direction in input (by customer)

DRAFT ANALYSIS:
It is a tool that allows the designer to check in advance whether the part they are designing can be removed easily from the mold being used to make it. A functional part for injection molding must have draft angles that face both the cavity and core sides. This will reduce the risk of damage to the parts and ensure that part can be ejected from the mold easily.

When the draft angle is provided the sticking tendency of the part during removal becomes minimum because as the part ejects contact between surfaces breaks just after moving a little distance which leads to the reduction in friction and easy removal of the component. Generally a 3degrees draft angle is recommended on the surfaces and 0.5o on ribs and screw bosses.

In CATIA before doing draft analysis first change view mode as material.

PUBLICATON:

Publication is used for easy access of the surfaces or components to work or view them.
MOLD:
It consists of two half that upon closing and filling with a filler material we get a component for which it has been designed and made. These two half are known as core and cavity in manufacturing industry. In the following figure ((fig.2) fixed half and the moving half together make the mold.
CORE:
Male portion of the mold is called core. It gives the internal shape to the component. Simply these are the projections on first half of mold.
CAVITY:
Female portion of the mold is called core. It gives the external shape to the component. These are depressions on the other half of the mold.
CORE AND CAVITY DESIGN:
The Mould Core & Cavity are the shaped sections in either half of the mould which give the final shape to its plastic product. The hot molten material is injected into mold where it sets hard into shape. The design of the core & cavity is essential to get the exact end product.
PARTNG SURFACE:
It is the surface that seperates the core and the cavity blocks from each other.
PARTNG LINE:
It is an intersection curve that seperates the component from rest of the parting surface extending beyond the component (generally flash if any).

Fig.2 https://www.youtube.com/watch?v=asEtaBiDZW8&ab_channel=TECHANICALGURUINJECTIONMOULDING

PROCEDURE TO CREATE THE TOOLING AXIS
If the component is symmetric about one or more plane then bisection method is best
suitable. The procedure is as following:

For the given surface the tooling axis has been created using bisection method. Refer the following diagrams

CREATION OF CLASS-B SURFACE
By using offset, fill and join features class-B has been created.

CREATION OF CLASS-C SURFACE
By using extract, boundary, smooth curve, sweep, multi-section surface, trim and join features class-C has been created.

CREATION OF CLOSED SURFACE
By using trim feature closed surface has been created.

CREATION OF CLOSED BODY
By using insert body and close surface feature closed body has been created.

CORE BLOCK DESIGN
To create core block the following procedure is adopted.

CAVITY BLOCK DESIGN
CLASS-B surface will act as the parting surface for cavity design. So trim CLASS-B with the extruded
and filled surface to get the cavity block surface. And to get solid cavity block insert body and use
close surface feature.