Attachment Feature Creation - Screw Boss & Dog House

AIM :

To create the Screw Boss and Dog House for the Centre Console Coin Holder.

OBJECTIVE :

• To make sure that the model meets the design rules for rib creation.
• To create the Tooling axis using bisecting method.
• To perform Draft analysis on the component.

SCREW BOSS :

• Bosses are commonly used for attacchment and assembly of plastic components.
• They are used to aid in the assembly of molded parts by providing a channel for a screw.
• Bosses must not merge into side walls as they may lead to the formation of sinks.
• Open bosses can be used near a standing wall.

• The Boss thickness can be taken as 0.6 times the thickness of the component.
• A Draft of 0.5 degrees per side is the maximum limit.
• Height to Diameter ratio must be 3:1.
• Optimum fillet radius can be taken as 0.25 mm which is optional.

DOG HOUSE :

• Dog house is an engineering feature used in plastic trim design as supporting feature.
• A Draft of 1.5 degrees per side is the maximum limit.
• In case of a slide 3 degrees of Draft can be provided
• At the intersection part dog house wall thickness must me less than or equal to 40% of the wall thickness of the component.
• It's height should be between 3 and 6 mm.

PROCEDURE :

Creating Tooling Axis

• Initially a base surface was extracted from the Class A to create a center point.
• An axis system was created upon this point.
• The Intersect feature was used to obtain a boundary of the Class A intersecting at the mid plane.
• Once the check for the discrepencies in the boundary is done, the Tooling axis was created from thr mid-point.

Creating Screw Boss feature

• Initially the base surface from the plastic component was extracted.
• A sketch for the rib was created on the surface consisting of a hole and a circle.
• This part was extruded upto a certain height.
• Another sketch was created for a boss.
• The boss was created using the Thicken feature in the pad command.
• The necessary drafts and fillets were created.

Creating Dog House feature

• Initially a sketch was created on the base which was extracted.
• The dog house outer profile was created using Sweep feature With draft direction alone the tooling axis with a draft angle of 1.5 degrees on the outside.

• An offsetted surface from the base was used to close the top portion of the dog house using Trim feature.
• The necessary fillets were provided to the surface.
• An intersection part was created at the inner side of the dog house unit.
• A Draft of 0.5 degree wa given on the innerside of the dog house.
• A second tooling axis was created perpendicular to the main tooling axis in the Z direction inorder to accumulate the inner cavity of the dog house unit while machining.
• Another screw boss was added upon the dog house using the Translate feature.

Draft Analysis

• The Drafting analysis was performed using the Feature Draft Analysis command.
• Using this command the compass was set on the main tooling axis and the Draft angle was changed to 1.45 degree.

MODEL RESULTS :

Feature tree

Front view

Top view

Side view

Isometric view

CONCLUSION :

• The creation of Tooling axis and Draft analysis were performed.
• The Screw boss and Dog house unit was created
• The necessary screenshots and files were attached.