Week 8 - Challenge 5 - Core & Cavity Design
AIM: To Create the Core and cavity blocks for the switch bezel design.
Draft:
Draft is an angular tapering given at the design stage to every Plastic Component that has to be manufactured. It is given in the direction of the Mold Movement. The Draft allows the parts to release easily from the mold without creating friction between the surface of component and the core and cavity plates.
When a Plastic component cools down inside the mold, the natural tendency of it is to shrink and attach to the core or cavity half. The movement of mold opening causes friction on the walls of the component as well as the core/cavity blocks. This reduces the life of the mold as well as the component itself. The component may also have rough surface finish as well as weak structure due to this. This problem can be solved by giving draft to the component.
Most applications require minimum draft angles of around 0.5° to 1°, however 3° draft angles are widely accepted for cost saving purpose. 7° Draft angles are given to textured surfaces like Instrument Panels. Minimum possible draft angles are given to screw bosses ribs and stiffeners due to their critical nature.
Draft Analysis:
The Draft Analysis command enables you to detect if the part you drafted will be easily removed from the mould. 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 of angles along a defined draft direction using colour codes. It highlights the regions of draft using colours. . Draft analysis is the first step performed after receiving the Class A of the component.
Tooling Axis:
The direction in which the mold or core and cavity opens is the tooling axis. Part Drafts are designed along this axis.
Class-A Surface:
In automotive design, a class A surface is any of a set of free form surfaces of high efficiency and quality. It is the visible aesthetic surface of any automotive component.
Draft Analysis on BASE BRACKET :
1) Check the class-A surface :
Check the Class-A surface for any discontinuities in the surface using join operation, boundray operation and disassembly operation.
2)Creating Tooling Axis:
First create a dummy tooling axis as per the given class-A surface. In this case we have chosen Z axis as dummy as it doesn't interfere with any slots or holes.
In this case we have taken intersection in Y direction, X Direction and created a Tooling axis by creating two lines over the intersection using bisecting line command select the two lines to get one line name it as tooling axis in Y direction, Now same as in X direction in the X direction we have only one face so create one line with referance to the intersection in X direction and create a line using point-angle name it as tooling axis X direction. Now bisect the X and Y tooling axis to get one final tooling axis.
After creating the tooling axis change the visualitaion to the material. Go to insert click on Analysis and select Feature Draft Analysis and perform draft analysis on the Class-A surface
Draft analysis of final component:
Core and Cavity Creation:
Parting surface:
Injection mold has two major components the movable halve and the fixed halve, during injection molding process, these two halves are pressed tightly and form 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:
The parting line is where the two halves of the mold meet around the parameter of the part. All parting lines need to seal properly when the mold is clamped in a molding machine. If the parting lines are too loose or have excessive wear, the mold will “leak” plastic over the parting line during the molding process.
Core Block:
Cavity Block:
CORE AND CAVITY BLOCKS:
