Attachment Feature Creation for Coin Holder-Screw Boss & Dog house

Attachment Feature Creation for Coin Holder

OBJECTIVE: The main aim of this challenge is to create screw boss and dog house for Coin Holder Plastic component following rib design rules and to perform draft analysis for the plastic component created.

Taking the Thickness of the component to be 2.5 mm

Tooling axis: The direction in which the mold or core and cavity opens is the tooling axis.

Tooling Axis creation:

Using the point created on base surface a line normal to surface will be created and treated as a tooling axis.

SCREW BOSS CREATION:

Sketch for creation of screw boss is

Sweeping along the tooling axis direction with draft angle will results in

For the support for screw boss ribs will be created for support following the design rules for ribs

The screw boss with ribs as support and providing draft for the ribs

Design rule check for the screw boss:

• Draft - 0.5 degrees on walls of boss
• Thickness - Typically 40%* of the nominal wall at the base.
• Height to Diameter Ratio - 3:1
• Radii - 0.25mm maximum radii.

All these rules and guidelines were followed while creatin the screw boss.

DOG HOUSE CREATION:

The basic sketch for creation of dog house is

The profile is swept along the tooling axis with draft to certain height and the surface is thickened following the design rules for dog house creation.

Draft is provided for the inner walls.

Fillets are applied and the lower portion of the dog house profile is achieved by splitting the body with the surface.

The draft is provided at the necessary locations and fillets are also given.

Tooling axis will be created for the clearance of Dog House

Design rule check for dog house:

• Doghouse wall thickness at the intersection of the part wall should be 40% or less than the main wall stock
• Height of (B) should be between 3.0 – 6.0 mm

Draft Analysis for Dog House:

The main use of the dog house is to provide support and to avoid sink marks such that screw boss will be placed on the dog house to achieve better results.

Draft analysis for final plastic component:

The final views of the Coin holder are: