Week 11 - Project - A pillar Design with Master Section

1) AIM :-

Create the A pillar plastic part from the given Class A surface, considering the design rules using master section and perform the draft analysis.

2) INTRODUCTION :-

A. 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, 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 oher engineering components are built on the B-surface.

B. MASTER-SECTIONS :-

Master sections are the guides for design requirements which decide the component packaging after technical (Styling, Concept or Class-A) surfaces.

A. Concept development in BIW. Concept & Feasibility.

B. Concept design / Design support and feasibility study.

C. Concept surface description.

3) OBJECTIVE :-

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

4) 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.

A. 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.

5) PROCEDURE FOR CREATION OF MAIN TOOLING AXIS :-

• Check the best possible tooling direction by manually adjusting the compass.
• By analysing it is found that y axis as tooling direction would clear most of the faces without any difficulties.
• Now a create point on center of gravity of A PILLAR using measure inertia.
• Then create a line in Y direction using CG point.
• Perform draft analysis to find whether the given axis clearing the draft analysis.
• Colour it yellow and publish it.

6) SIDE CORE AXIS :-

Side core axis is the moving direction of the side core because the inner side of the dog house cant be cleared by using the main core. so, create it by extracting the master section.

Colour it pink and publish it.

7) DRAFT ANALYSIS OF CLASS A SURFACE :-

Draft analysis is done to know wheather the part will be easily manufacturable by the given draft angle or not. It will ensure that the part will not stuck in the core and cavity.

PROCEDURE TO PERFORM DRAFT ANALYSIS:-

1. Right Click on Tab < Go to Analysis < Feature Draft analysis
2. Put the View Mode in material option
3. Align the compass with the tooling direction line
4. The surface will turn into green colour it means the part is manufacturable with the given draft angle.

We have given minimum 3deg. draft and the green colour parts are easily removed from the mold.

8) CLASS-B SURFACE CREATION :-

Class-B surface means thickness of a part it is not visible and is inside part. In other words, 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.

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

A. CLASS B SURFACE WITH 2.5 MM OFFSET AND SECTIONAL VIEW :-

9) CLASS-C SURFACE CREATION :-

Surface that joins class-A and class-B surfaces 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 surfaces with reference to surface and tooling axis by multi extracting the CLASS-A boundaries.
• Join the sweep surfaces by using commands like extrapolate, trim, multi section surface.
• Finally join all the sweep surfaces and ensure the continuity of the CLASS-C surface.

10) CREATING THE FINAL SURFACE :-

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

Make a solid part body using the CLOSE SURFACE command in INSERT then SURFACE BASED FEATURES in the PART DESIGN WORKBENCH .

11) 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 thickness should be 40% of the main wall thickness T
• Minimum width of the dog house is 12 mm.
• Height of B should be 3-6 mm
• Minimum draft for the do house is 1.5 degree to die draw.

PROCEDURE :-

A- First we have extracted and extruded the line of the mastersection.

B- Then we trimmed this to make the body of the dog house

C- We have converted it into a thick surface and give draft of 1.5deg. to it

D- We have created a cutout for the dog house of height 3.5mm.

E- We have created a sketch to make ribs and thicken the extruded surface of sketches it to make it a solid surface

F- Created a sketch for the upper cutout, then pad it and remove it from the body to make this cutout.

G- We have splited the cutout with the main dog house body to make the final Dog House Component

12) 3D PART MODEL IN VARIOUS ORIENTATIONS :-

A. ISOMETRIC VIEW :-

B. FRONT VIEW :-

C. SIDE VIEW :-

D. TOP VIEW :-