Week 9 - Attachment Feature Creation - Challenge 2

Screw Boss Design

Bosses find use in many part design as points for attachment and assembly. The most common variety consists of cylindrical projections with holes designed to receive screw threaded insert or other type of fastening hardware. As a rule of thumb the outside diameter of bosses should remain within 2.0 to 2.4 times the outerside dia of the screw.

Creation of screw boss

• Outside diameter of boss: It is equal to 2.0 to 4.0 times the outer dia of the screw insert
• Draft: Inside and outside surface draft should be greater then or equal to 0.5 deg
• Fillet: It should be maximum 0.25 mm
• Thickness: It is typically 40% of the nominal value at base
• Height : It must be in 3:1 ratio

Creation of Dog House

• Doghouse wall thickness: It should be 40% or less than main wall thickness
• Draft: The minimum draft for a doghouse is 1.5 deg
• Width:The minimum width fpr a doghouse is 12mm
• Height:It should be between 3 to 6 mm
• Width to height ratio: 3:1 ratio is consided

Final Assembly

Draft analysis report

• The green colour represent angle of surface with respect to tooling axis being greater than 3 deg
• The blue colour represent angle between 0 and 3 deg
• The red colour represent angle lesser than 0 deg