Week 8 - Challenge 5 - Core & Cavity Design

AIM:

To create the Core and cavity blocks for the switch bezel which we have designed in the earlier challenge.

THEORY:

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 color ranges identifying zones on the analyzed element where the deviation from the draft direction at any point, corresponds to specified values.

PARTING SURFACE:

Generally injection mold has two major components: the movable halve and the fixed halve, 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 surface design principles:

Parting bsurface design directly affects the product quality, ease of construction and opearation of the injection mold, the mold design is one of the key factors to success.

Principles to follow to design Parting surface:

1. Design the injection mold simple as possible. Avoid or reduce side parting as much as possible to reduce complexity of the mold making. 2. 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,

3. Ensure the dimension accuracy of the molded parts. Try to make the parts similar dimension accuarcy requirements in same mold to reduce manufacturing and assembly errors.

4. Ensure apperance requirement of molded parts,finish or mismatch usually occurs on parting surface, so the parting surface should not be

designed on high quality requiremnent surfaces.

venting.

DESING RULES OF CREATING CORE AND CAVITY:

To create a plastic part there are two major components core and cavity. The core has the impression and the cavity have the depression.

• The proper draft should be given to the part so that the part can be ejected from the core and cavity.

• Minimum 3 degree draft should be given to the Class C surface. If the part has 0 degree draft then there will be friction occurs in the core and cavity.

• The side core should be avoided because the manufacturing cost of the component increases.

The parting line is the line that split the mold into two halves the core and the cavity. So the parting line should be always in the Class B surface so that we can not see the parting line.

• Avoid sharp comers as the cost to manufacture the sharp corner is very high.

The thickness of the part should always have uniform thickness throughout the part..

PROCEDURE:

When you look at the part we have designed the color highlighted region side is the core side since it have the projections here we are extrapolating the class A so that we can use it for trimming purposes while creating core and cavity blocks

if we can observe from draft analysis we have done on this component in the previous callenge the A surface and C surface had tooled along A

side ile., "main tooling axis" direction.

CLASS A OF switch bezel :

CLASS B:

DRAFT ANALYSIS:

CORE PART:

CAVITY PART:

PARTING LINE:

JOINING OF CORE AND CAVITY

TRANSLATING CORE AND CAVITY :

Finally created core and cavity block for switch bezel.