Week 9 - Attachment Feature Creation - Challenge 2

AIM:- To create Screw Boss and Dog House for the Center Console Coin Holder considering the design rules and perform the Draft Analysis on the final component.

Screw Boss:-

Screw Bosses find use in many part designs as points for attachment and assembly. The most common variety consists of cylindrical projections with holes designed to receive screws, threaded inserts, or other types of fastening hardware.

General Guidelines for Bosses

• Draft - 0.5 degrees on walls of boss
• Thickness - Typically 40%* of nominal wall at base.
• Height to Diameter Ratio - 3:1
• Radii - 0.25mm maximum radii.
• Boss gussets must meet rib guidelines.
• Need to plan ahead for type of ejection.

- If less than 25mm tall, draft is not required when sleeve ejetion is used

- Over 25mm tall, draft is required on outside wall only if sleeve ejection is used

- If sleeve ejection not used, draft is required on all walls.

Procedure for creating the Screw Boss:-

First extract the base surface of the part and create a point on center and create the sketch on it.

consider inner diameter is 5 and outer diameter is = inner dia+(0.6*t)=8 (t=thickness of the part)

And then pad it with Height of 3:1 ratio

For supporting to create ribs with thickness of 1mm and unian trim with screw boss. And Draft the side wall with 0.5 degree.

Draft the wall with 0.5degree.

and then unian trim with the main body

and then give the fillets to edges with radius of 0.25mm.

final screw boss is created.

Dog House Creation:-

The Dog house is an engineering feature used in plastic design. Dog House are used as sapporting features. Sometimes other engineering featrues snaps, locators supported by the dog house. And Dog house are prevent the backage of the component during ejection from the mould cavity.

Procedure:-

Extract surface on which you want to dog house

create a sketch of the dog house

sweep that with draft diretion.

and then close the top surface, and convert into part body. with thickness of 2mm.

final dog house component is created.

Create Tooling Axis:-

Tooling Axis

Tooling Direction is basically the direction that the core pulls apart from the cavity. And some components have ribs, pockets, walls.... are going to be drafted based on the Tooling Direction. So make sure the tooling direction which is cover all phases of the components and Core pull apart from the Cavity, nice and clean.

Here using Bisecting method to create a Tooling Axis. There are so many methods to create a Tooling Axis for differnt type of components.

Bisecting Line:-

• First visually check given class A surface for to find out tooling axis which is cover all faces. Herer in this case viewing from Z direction we can clear the face in tooling
• Most of the cases we create the point in holes and pockets of the part, because the holes and pockets is to create a problems when we do the daft ananlysis so we creat a point in mid of the hole. and create a axis system on it.
• And using intersect command intersect the surface and draw the lines on the walls and create a disect line with help of b isecting line command.

For the inner phases of the Dog house Create a side core to cover it. for that create a line perpendiculer to the main tooling axis

Draft Analysis:-

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.

• To perform the darft analysis the view parameters are first set to material mode.
• then go to insert -analysis-feature draft analysis, the following window will be appeared.

• First select the axis system and drag the axis system to the tooling axis and lock the orientation. This axis system defines the draft direction according to the tooling axis
• Switch on the colour scale and set the draft value 3 degree using colour scale and it will be displayed in green colour any draft angle below 3degree will be shown in red colour.
• Now select the runing point tool to measure the draft angle at the various locations.

And then side core draft analysis

Side core Draft Analysis

Draft Analysis on Main Tooling Axis

Result :-

The Screw Boss and Dog House for the coin holder has been created as per the design rules and draft analysis also done for the final component.