Screw Boss and Dog House Feature Creation

OBJECTIVE:

Creating the boss and Dog House for the Centre console coin holder considering the design rule

THEORY:

SCREW BOSS:

• Used in many part designs as points for attachments and assembly
• the most common variety is of cylindrical projections with holes designed to receive screws fastening hardware
• Bosses that merge into sidewalls should be avoided

DESIGN RULES FOR 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.  

DOG HOUSES:

• Helps to avoid sink marks
• solves the length issues(ex: screw bosses can be formed at 100mm form B-surface)
• always design houses perpendicular to the tooling axis

DOG HOUSE DESIGN CONSIDERATIONS:

• "C" is where the doghouse contacts the backside of the surface

•  Doghouse wall thickness at the intersection of the part wall ( C ) should be 40% or less than the main wall stock ( T ). 

• Height of  ( B ) should be between 3.0 – 6.0 mm

PROCEDURE:

• SCREW BOSS:
  • Extract the surface on which you want to add boss
  • create a sketch of the boss
•  
  • create a new part body
  • create Pad 
•  
• 
  • Draft the obtained body, Neutral element should be the extracted surface
  • Give required fillets
  • Create ribs for support in a separate part body
  • union trim with the main body
• 

• DOG HOUSE:
  • Extract the surface on which you want to create a dog house
  • create a sketch of the dog house
•  
  • Extrude or sweep and give draft
•  
  • close the upper open surface
•  
  • make the solid body by using thickness feature in a separate part body
  • create side core axis which is used for the drafting of inner surfaces of the dog house
  • Give required fillets
• 
• 

DRAFT ANALYSIS OF SCREW BOSS AND DOG HOUSE: