Week 9 - Attachment Feature Creation - Challenge 2

ATTACHMENT FEATURE CREATION - CHALLENGE 2

JEEVA R

AIM:

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

GENERAL GUIDELINES FOR BOSSES AND DOG HOUSE:

• 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.

"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.

SCREW BOSS DESIGN:

Screw bosses are attachment features designed on B surface of the component.

PROCEDURE:

Draw a positioned sketch of inner circle of dia 5.2mm and outer wall should be 0.6*T on one side, so outer dia = 2*(0.6*2.5)+5.2mm = 8.2mm.

Pad the sketch with main tooling direction cosidering height to dia ratio 3:1.

Give draft of 0.5 degree with tooling axis.

Now to support the screw boss, we need to create ribs using rib design rule.

Draw a sketch of lines and pad them with thickness of 1mm to required height.

Draft the rib faces with 0.5 degree.

Union trim ribs with screw boss and Assemble it to the coin holder.

Add minimum fillet 0.25mm to rib faces.

Use this screw boss created by copying and pasteing, translating wherever required.

DOG HOUSE DESIGN:

Extract the base from class A surface and offset it to the part thickness of 2.5mm.

Draw a center rectangle with one side open for a dog house.

Using sweep command, sweep the outer surface in tooling direction and draft it to 1.5 degree.

Cover the upper part by offsetting the extracted surface and trim it with the sweep.

Thicken the surface created to thickness of 2mm.

Now create a side core axis for inner surfaces of the dog house along Z direction and draft the faces to 0.5 degree along side core direction.

Now create B and C parameters of dog house as per design, extract the inner faces and offset them to 40% of part thickness, cover the top with surface measuring height between 3 - 6mm.

Extrapolate the surface and Split the thicken part with the surface created.

Provide draft of 0.5 degree to the inner flat surface also.

Give fillet to the inner and outer edges with 0.4*T = 0.4*2.5 = 1mm to inner edges and 1+ thickness = 3mm to outer edges and minimum fillet radius of 0.5mm to smaller edges.

Assemble the dog house to coin holder and place a screw boss on it.

DRAFT ANALYSIS ON SCREW BOSSES AND DOG HOUSE:

VIEWS:

TREE STRUCTURE: