Challenge

Week 9 - Attachment Feature Creation - Challenge 2

AAnkit Khatri6 Aug 2022

FEA

DOOR TRIM - DOG HOUSE

AIM:

Create the Dog House for the door trim considering the design rules as mentioned in the below image.

OBJECTIVE:

To design door handle from given class A surface.
Designing Class B and Class C surface.
Create the Dog House for the door trim.
Perform draft analysis on the final component.

Design procedure:

Checking Class A input for imperfections

The input class A surface is checked for discontinuities and joined together to get complete class A surface as one.

Tooling axis creation

Generally tooling axis is created using bisecting line method. But in the components where it has a bin, then the tooling axis is considered as a line normal to the base surface of bin. Same is done with this component. A line normal to base surface is created and considered as tooling axis.

Draft analysis of given class A

B surface creation

As usual, B surface is created using standard procedure by extract, untrim, extrapolate and offset commands. B surface of this coin holder is divided as base, side walls, top wall and outer surface. B surfaces of all these sub parts are created and trimmed together to join as single surface.

The offset distance is kept 2.5mm as component thickness is 2.5mm

Class C surface creation

Class C surface for this component is created using sweep command. All the ends of component surface are facing downwards, so the C surface will be created perpendicular to B surface.

To create C surface, boundary of class A surface and surfaces adjacent to boundary are extracted. Then sweep with reference surface command is used and surface is created at 90 degree.

Creating final closed volume, converting in solid body and draft analysis.

Once all surfaces are created, Class A, B and C surfaces are joined together to get the final closed volume. This closed volume is then converted into solid body using closed volume command in part design work bench.

DRAFT ANALYSIS OF FINAL PART BODY -

ATTACHMENT FEATURE CREATION - DOG HOUSE

Create the Dog House for the Door Trim considering the design rules.

- DOG HOUSE -

Dog house is an engineering feature used in plastic trim design. Dog houses are used as supporting feature. Sometimes other engineering features like snaps; locators etc. are mounded on them to increase their strength. Dog houses are subjected to draft analysis to prevent breakage of the component during ejection from mould cavity. Dog house and other engineering components are built on B-surface.

- IMPORTANT FUNCTION OF DOG HOUSE -

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

"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