Week 10 - Challenge 2- Attachment Feature Creation (Dog House)

Attachment Feature Creation - Challenge 2

AIM:

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

INTRODUCTION:

DOG HOUSE

Dog house is an engineering feature used in plastic design. Dog houses are used as support feature. Sometimes other engineering features like snaps, locators, and screw bosses are mounted on them to increase their strength.

Dog houses are subjected to draft analysis to prevent breakage of the component during ejection from the mould cavity. Dog house and other engineering components are built on the B-surface.

OBJECTIVE

• Create a Tooling axis for the given CLASS -A surface.
• Create the CLASS B and C surfaces of door trim using the given CLASS-A surface.
• Create a final surface model and convert it into a solid body using the close surface command in the part design workbench.
• Crea ate side core axis for the dog house
• Create Dog house on the B surface by considering the design rules.
• Perform draft analysis for both Class-A surface and Final part body.

Design Methodology

Class-A surface means visible surface. It gives the aesthetic of the component which is created by the styling team and gives to the part design engineer to create the part with all engineering aspects.

Given CLASS-A surface

Check for continuity of the given surface using Join or Boundary commands.

If there are no gaps on the A surface, create tooling axis.

Procedure for Tooling axis creation

• Check the best possible tooling direction by manually adjusting the compass.
• By analysing it is found thathe t y axis as tooling direction would clear most of the faces without any difficulties.
• Now extract any surface and create a mid-point on it.
• Then create a dummy axis creating a line on the point and direction along the y-axis.
• Perform draft analysis to find whether the given axis clears the draft analysis. If not create a new tooling axis.

CLASS-B surface creation

Class-B surface means the thickness of a part it is not visible and is inside part. In other words, the Class-B surface is a surface below a certain thickness from the class-A surface. This is the surface that contains engineering aspects of a model.

• Crean ate offset surface of Cin LASS-A about 2.5mm inward direction.
• Check for discontinuity and rework on the offset surface using extract, multi-extract, multi sections surfaces.
• Join the surfaces and ensure the final CLASS-B surface created has no gaps.

CLASS-C surface creation

The surface that joins class-A and class-B surfaarethe s is class-C surface. Class C is often specified for interior surfaces not readily visible, surfaces that will be covered by another part when assembled

• Create the sweep concerningerence to the surface and tooling axismulti-extractingting the CLASS-A boundary
• Join the sweep surfaces by using commands like extrapolate, trmulti-sectiontion surface.
• Finally join all the sweep surfaces and ensure the continuity of the CLASS-C surface.

Creating the Final surface

• For creating the Finals door trim surface, join the CLASS-A and CLASS-C surfaces together.
• Then Extrapolate the B surfacea little bit outward direction to make sure that there would not be any gap when trimming with the joined surface.
• Then trim the extrapolated CLASS-B surface wthe ith Join surface (CLASS-A and CLASS-C).

DOG HOUSE Creation

• Dog houses are designed to avoid SINK MARK created on the CLASS-A surface by screw bosses and to solve the length issues when giving screw bosses which need to be assembled to other components.
• It is also useful when perpendicular screw bosses are required on the part to the tooling direction.

"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 ).

The height of ( B ) should be between 3.0 – 6.0 mm

Dog house design procedure by considering the design rules:

Extract the surface on which we want to create the dog house and create a sketch on a plane.

The height of ( B ) should be between 3.0 – 6.0 mm by considering the design rule

here we offset the class b surface to 4mm

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

we offset the 1mm from the side wall by considering the design rule

Draft Analysis on the final component :

1. The part created has to be changed to the material mode in the display frame.
2. Compass is enabled and aligns it along with the tooling direction.
3. The lock command is then applied to fix the compass along with the tooling axis.
4. Color codes are classified and Draft angle is applied.
5. Running point analysis is used to display permissible draft angles.

Draft analysis on the dog house considering the side core axis as our tooling direction

Conclusion :

Hence, the dog house for the door trim was created by considering the design rules, and the Draft analysis performed on the final component is successfully done.