Week 9 - Attachment Feature Creation - Challenge 2

Screw boss and dog house design on coin holder

Aim:

Create the boss and Dog House for the Centre console coin holder considering the design rules.

General Guidelines for Bosses:

• 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.
  

Procedure:

Screw boss:

Injection molding design, boss features are frequently used. They are used to help with the assembling of molded pieces by providing a screw channel.

Create sketch for screw boss design

1. Using an extract surface from bottom of the coin holder part as the reference, a sketch was created with two concentric circles.

2. The inner circle is 5.2mm and outer circle is 8.2mm diameter which gives around 3mm wall thickness for the component and hence was proper according to the screw boss design guide lines

3. Using the pad tool, the sketch was extruded to the height of 12mm, forming the screw boss

4. A draft of 0.5 degrees was applied to the outer surface of the screw boss, with the base of the coin holder part as the neutral plane and maim toolingh axis as the pulling direction.

5. The screw boss is strengthened using ribs to support the height.These ribs were designed using symmetric lines across the screw boss.

6. These lines were extruded to a height less than the height of screw boss(=10)

7. A proper draft (0.5 degree) was applied on the draft

8. Sharp edges were smoothened using fillet of 0.25mm

9. The inner portion intersect with screw boss was trimmed using union trim tool.

Create sketch for dog house design

Dog house

A dog house is an engineering feature used during construction of plastic trim. They serve as supplementary feature. Other technical elements like as snaps, locators, and so on are sometimes installed on them to boost their strength.

1. First step is to draw a sketch of dog house and making it iso-constrained.

2. sweep the sketch using sweep command

3. To built a roof of the dog house off-set the base.

4. Thicknen the surface with the pad option

Undercut of the dog house

1.This is created with the dog house so that sink marks and flow lines do not appear on the surface due to thickness of the dog house

2.Extract thge dog house interior and offset it by 1 mm

3. Use the offsetted base and trim it with above offsetted surface

Draft analysis