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

Tooling Axis :

Class-A surface is first analyzed to create the tooling axis. where the molds pull apart in injection molding. Tooling direction is essential for plastic product design as it decides the direction for mold separation.

To create the tooling axis first we have to check the best suitable direction for tooling by using the compass. the y direction is suitable for creating the tooling axis because in the y direction most of the surfaces are clearing while performing draft analysis. Generally tooling axis is created using bisecting line method but here A line normal to the surface is created in the y direction and considered the tooling axis.

Y direction

Draft analysis of Class- A

After creating a tooling axis we do the draft analysis. Before drafting we have to make sure that in the view mode it is selected for the materials.

After selecting the feature draft analysis tool we drag the compass from its position to the tool axis. Then lock the compass. After that select anywhere on the component and it will give you the result.

We change the minimum draft for the component to 3°.

We can use the running point option to check the angle of the component.

CREATION OF CLASS B SURFACE:

In this component Creation of the class B surface first, we have to offset the entire model by 2.5mm outward some of the surfaces give offset error and ask for offset without these subelements click okay and work on the incomplete surfaces by using the multi-section surface command, sweep and different commands used to complete the class B surface.

CREATION OF CLASS C SURFACE:

We first extract the edges from the Class A surface with the help of the multi extract or boundary command which we create the path for a sweep for class C Like this, we have to create all separate sweeps and join them together. once all the sweeps are joined together we created a class c surface.

Joining class A surface and class c surface together

Then trim the class-B surface to join (A+C) this will make sure that we get a closed surface. We can check it using the boundary tool, if it gives an error that means that the component is closed.

Then We go to the part design workbench and use to closed surface tool to create a solid body.

hence, we created our final Solid component.

DOG HOUSE DESIGN:

Dog house: Dog house is an engineering feature used in the plastic trim design. Dog houses are used as supporting features. Sometimes other engineering features like snaps; locators, etc. are mounded on them to increase their strength. Dog house and other engineering Features are built on B-surface.

Design rules for Dog house creation

"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

Dog house Sketch

Side core tooling axis creation:

side core axis is created in the x direction on the same point as the main tooling direction created

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

Now we trimmed the surfaces and split the surface with the part body

finally, The dog house is created by considering the design rules.

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.