Week 8 - Challenge 5 - Core & Cavity Design

OBJECTIBVE: To Create the Core and cavity blocks for the switch bezel.

CORE: The core is the part which forms the internal shape of molding.it is respponsible for half of the molded part. actually core is the projection of the body

CAVITY: The cavity is the part which forms external shape of molding. Cavity is the depression of the body. these core and cavity combines to form a mould.

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 accuarcy reqirements in same mold to reduce manufacturing and assembly errors .
• Ensure apperance reqirement of molded parts,finish or mismatch usually occurs on parting surface , so the parting surface should not be designed on high quality requiremnent 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 fillng and venting.

PROCEDURE:

First extract the boundary of class A, then extrapolation the boundary and extrapolation the class A. length 15mm. using curvature and tangent in the new geometrical set named as core and cavity design.unhide the class B surface and joinwith the class C.

Trim the class A with the C surface. and trim the class B with trim5 these are the face which for core and cavity.

unhide the axis system draw a sketch as shown below make sure it is in a part design and then extrude it.

then trim this extruded surface with the parting surface

now fill it using fill surface command and join the filled surface with the last trim

and close the surface using closed surface option

intersect the both core and parting surface as shown below.

now extrude the sketch3 again and trim it with the class b surface

then fill the below surface using fill surface option

join both the surfaces and use close body feature this is our cavity

intersect the class b surface as shown below this is our parting line