Week 8 - Challenge 5 - Core & Cavity Design

AIM:

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

TOOLING AXIS:

It is the axis in which the direction of core and cavity opens.This is the very important step for production of plastic component.Most of the defect will done improper tooling axis creation by the plastic designer.

There are so many methods for creation of tooling axis.Intersect is the one of the method for creating the tooling axis.

BISECT METHOD:

For doing this you shoud find out what is the best tooling direction.For doing that rotate the part and see all directions and choose which direction will be comfortable.

Then create the point on the base mostly create the point where the hole or pockets are given and after that insert tooling axis in that point.Then first see in x direction it will clear the all faces of parts if not create a plane and intersect to each other.

Then create the mean line and go to y direction and do the same process we are done in x direction.Then bisect these lines to get the main tooling axis.This tooling axis can be cleared all faces of the part.

DRAFT ANALYSIS:

The purpose of draft analysis is to detect the part should be easily withdrawal from the core and cavity by using of different color ranges.

This analysis will be done by draft analysis command. For this command go to insert< analysis< feature draft analysis

These are the fallowing steps to do the draft analysis on switch bezel.First click the draft analysis command a window will be appeared and then change into material mode then click the compass and drag on the tooling axis. and then click on the part then the colour will changes of the part and you can change the value using scale option. Then a running point command used to find out the angle of part from the tooling axis.So you can modify the tooling axis by using compass to get proper results.

DRAFT ANALYSIS REPORT FOR SOLID BODY

CORE AND CAVITY DESIGN FOR SWITCH BEZEL:

CORE AND CAVITY:

A core is the one part of the mould and it is responsible for half of the molded part. Actually core is the projection of the body and cavity is the depression of the body. These core and cavity combines to form a mould. Then the plastic material injected into these mould to get a plastic part.

PARTING SURFACE:

Injection mold has two major components one is core and another is cavity 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

PARTING LINE:

It is the area in which parting surface and component meets 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 :

• Design the injection mold simple as possible. avoid or reduce side parting as much as possible to reduce complexity of the mold making.
• Ease of de-molding as far as possible, for instance the plastic parts should stay in fixed halve of injection mold and should ejected by ejection system avoid , side de-molding action,
• Ensure the dimension accuracy of the molded parts ,try to make the parts similar dimension accuracy requirements in same mold to reduce manufacturing and assembly errors.
• Ensure appearance requirement of molded parts,Finish or mismatch usually occurs on parting surface,so the parting surface should not be designed on high quality requirement surfaces.
• Ensure adequate venting.if possible parting surface should be place at the end of the mold flow.this is going to be advantage of filing and venting.

CORE DESIGN:

To extrapolate class a surface

Trim class a with class c to get inside portion

Now trim the b surface with the output of class a & c that will be the parting surface with respect to area. Extrude the sketch overall through the tooling direction are trim it with parting surface

Final output of core design

Part body of core

Similarlly, repeating the same as done for the cavity part and trim it on other side surface

Part body of cavity

Final close body surfaces of core & cavity are,

Parting surface and parting line

The core and cavity are translated to the certain value foe understanding

TREE STRUCTURE

RESULT :

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