Challenge

Week 9 - Project - A pillar Design with Master Section

HHarsha M S1 Dec 2022

DESIGNING A PILLAR USING MASTER SECTION:

AIM:

1) To improvise the Class B surface by resolving patches.

2) To create A pillar solid model with the help of improvised Class B surface.

3) To create B side features for the A Pillar using the master section given to us as an input.

4) To create main and side core tooling axis for A pillar and its B side features.

5) To do the draft analysis of the overall model of the A pillar including B side features.

INTRODUCTION:

Master sections development takes place during feasibility check and concept validation stages of the product life cycle. These are typically the guides for design requirements and which decides the component packaging after the development of the concept design, i.e class A surfaces.

Master section helps us to decide the feasibility of the concept design, the clearances, the packaging and the fixation strategy of a component before converting the concept design into a solid 3D engineering design.

During the period of vehicle concept design the evaluation of the master section performance depends mainly on the reference vehicle data and experience of structure design engineer.

Master Section Used in the A-Pillar Design

MATERIAL CONSIDERATIONS:

Automotive Industry has developed a broad range of ABS, PC/ABS, PP compounds, and Reinforced Elastomers to enhance safety, performance, and the appearance of vehicle interior pillars.

Interior pillars must provide multiple properties that support a high-quality aesthetic appearance, high impact protection, safety functionalities, and medium to high heat resistance. When airbag deployment functionalities are required, interior pillars also need materials with low-temperature impact resistance. For unpainted pillar applications, low-gloss aesthetics and easy flow are required.

The family of PULSE™ GX Engineering Resins offers appropriate features and supports requirements such as low gloss, low-temperature impact resistance in combination with low density and an easy flow that enable weight and cost reduction. PULSE™ 2000EZ Engineering Resin is a favorable material of choice in the North American market; it provides an outstanding combination of good, low temperature ductility with very high heat resistance and easy flow, enabling thin-wall part designs.

As an alternative, cost-effective materials solution for pillars without airbag deployment, Trinseo Automotive offers customized MAGNUM™ ABS Resins with either lower or sufficient heat resistance

Besides these ABS and PC/ABS solutions, INSPIRE™ Performance Polymers (low emission, low gloss, and good scratch resistance) and VELVEX™ Reinforced Elastomers (very low gloss, very good scratch and mar resistance) meet the needs of cost-efficient interior pillars.

TYPES OF PILLARS IN A CAR:

For this A-PILLAR model , the engineering feature which has been given in the master section is DOG HOUSE following are the design considerations for the same.

DOG HOUSE:

Dog house is an engineering feature used in plastic trim design as supporting feature.
A Draft of 1.5 degrees per side is the maximum limit.
In case of a slide 3 degrees of Draft can be provided
At the intersection part dog house wall thickness must me less than or equal to 40% of the wall thickness of the component.
It's height should be between 3 and 6 mm.

TOOLING AXIS:

Considering the Ejection from the cavity of the mould after manufacturing the interior trim must have the nominal 3-degree draft angle.
Hence the tooling axis is created by considering the above factor.
The direction in which the mold or core and cavity opens is the tooling axis.
In this case below is the tooling axis that I have used.
The Line in the ORANGE colour is our tooling axis.

CLASS A SURFACE:

In automotive design, a class A surface is any of a set of freeform surfaces of high efficiency and quality.
It is the visible aesthetic surface of any automotive component.
Class A surface refers to those surfaces which are visible and abide to the physical meaning, in a product.
This classification is primarily used in the automotive and increasingly in consumer goods industry.
It is a requirement where aesthetics has a significant contribution.
For this reason, the exterior of automobiles is deemed Class-A.
Below is the CLASS A SURFACE that was given for this model.

CLASS B SURFACE:

Class B surfaces are Engineering Surfaces which are invisible to the eyes or often on the back side of the Class A surfaces.
It is mainly the thickness of the component or Class A.
These surfaces need to be designed as per the Class A surface i.e., the continuity, thickness of the component, functionality etc should be maintained.
These surfaces include the main engineering features such as Screw bosses, Ribs, Snaps, Stiffeners and fixations.
B surfaces also do not contain any aesthetic styling content and textures since it is not visible to eyes.
Below is the image of CLASS B SURFACE that I have created.

CLASS C SURFACE:

Class C surfaces are connectors between Class A and B surfaces.
This surface connects both A and B surfaces along the Tooling Axis.
It contains the draft as per the design.
It is basically the thickened surface between both A and B surface.
Below is the Class C surface that I have created for this model.

CLOSED SURFACE:

Now the class – A and Class- C surfaces were joined together by removing the gaps in-between them with the help of extrapolation and Trim surface.
Then, by defining the part body by using the Closed Surface command in Part Design, the component's solid body is created.

DRAFT ANALYSIS:

Draft Analysis is a tool in CATIA which identifies the zones which deviates from the specified values of angles along a defined draft direction using colour codes.
It highlights the regions of draft using colours.
Draft analysis is the first step performed after receiving the Class A of the component.
Draft analysis should be passed in order to make the plastic component manufacturable.
Acceptable draft angles are used as range for draft analysis that is 0 to 3 degree.
For Dog House draft given is 0.5 to 2 degree outside and 0.5 degree inside.

SURFACE: