Project

Automotive B - Pillar Design with Master Section

SSouradip Halder5 Jun 2023

AIM & OBJECTIVE: To create the B-Pillar's Plastic component from the given Class A Surface using the Master Section that is provided while following all the design rules.

INTRODUCTION:

Types of Pillars and their importance in the Automotive Industry:-

These pillars standing at the vertical or near-vertical (slightly inclined) position are structural supports for the car's roof and window areas.

They are pretty important as they provide a strong foundation to install the glass (windscreens, rear, and side windows) of your car. Also, these are strong enough to hold the entire roof (even with roof racking to carry additional weights).

There are several pillars your car can have, and each has got a name. Pillars are named “A”, “B”, “C”, or “D” (in larger vehicles), if you move from the front to the rear end of your vehicle.

The number of pillars will vary from car to car.

For example, most sedans and hatchbacks will have three (A, B & C) pillars whereas larger cars like SUVs will have all four (A, B, C & D) pillars.

Hardtop structures (often referred to as pillarless hardtops) will have only two (A & C) pillars.

ROLE OF THE B-PILLAR:

Furthermore, B Pillar is the most complex component/structure of the vehicle body. It is because the front door closes on the B pillar while the rear door hinges on it. Manufacturers make the B pillar or the center pillar of steel in vehicles. Manufacturers weld it to the roof panel on top and the vehicle’s floor pan at the bottom. This pillar provides structural support to the vehicle’s roof.

Manufacturers skipped the B pillar while naming other pillars. Hence, some vehicles do not have a B Pillar. The carmakers call those cars ‘Hardtops.’ Instead, the vehicle specification shows the rearmost pillar as the C pillar. The manufacturers offer the Hardtops in nearly all four-door body styles. These include sedans, coupes, and wagons/MPVs. The cars without B pillars increase passengers’ visibility. However, they have limited structural support and strength. General Motors later started providing B pillars in Hardtops. Thus, it created a new vehicle body type and thereby broadening the definition of Hardtops.

Firstly, we have to create the required Tooling-Axis for the given Class A Surface while meeting the requirements of the necessary Draft Angle & then perform the Draft-Analysis Operation on the Class A Surface itself.

After that, we have to create the required Class B & Class C Surfaces using which we have to make the Final Plastic Component and perform Draft Analysis on it.

MAIN REPORT:

Types of Surfaces and their importance for an Automotive Plastic Designer:

Class A Surface: Class A is an aesthetic surface with the highest quality finish. Most Class A Surfaces for an Automotive Component are made using 'Autodesk-Alias' based on the final Concept-Sketch. All Class A surfaces should have 'Curvature-Continuity', meaning the continuity between the surfaces should share the same boundary. It is taken as a reference by the Automotive Plastic Designer to create 'Class B' and 'Class C' Surfaces.

Class B Surface: The Class B Surface resides below the Class A Surface at a certain thickness. It is created using Engineering Principles that consist of all the necessary features such as Ribs, Bosses, Snaps, etc. This surface isn't visible to the observer from the outside.

Class C Surface: The Class C Surface is the surface created between the Class A and Class B surfaces to join them with each other.

Now, we will begin by checking the State of Connectivity for the Class A Surface and ensure that there are no gaps between the surfaces as all the surfaces should be joined well together with each other and shouldn't consist of any discontinuities between them.

Our Class A Surface:

There are two methods to inspect the State of Connectivity for the Class A Surface:

1. Using the 'Join' Command' from the 'Operations Toolbar':

First, we'll click on 'Join Command' and select our Class A Surface. Then, we have to ensure that the 'Check Connexity' option is marked as shown in the images below. It will check for any gaps that may be present between our surfaces. Then, we'll click on the 'Preview' button and if it doesn't show any 'Connexity Error' on our surface then it means our surface is well-connected and there are no discontinuities between it.

In our case, there are no 'Connexity Errors' for the given Class A Surface.

In case there is a 'Connexity Error', we can fix it by increasing the 'Merging-Distance' up to 0.003mm following the industry standard.

2. Using the 'Boundary' Command' from the Operations Toolbar:

In this case, we have to click on the 'Boundary' command and then select the Class-A Surface. After that, we'll click on the 'Preview' button to highlight all the boundaries that are on the Class-A surface and check if there are any internal boundaries other than the outer edge boundaries.

In our case, there is only one boundary present on the Class-A Surface which is the Outer-Edge Boundary and hence we can conclude that all the surfaces are well connected.

CLASS A SURFACE WITH MASTER SECTIONS:

PROCEDURE TO CREATE THE MAIN TOOLING AXIS:

Since we have a Master Section provided to us using which we have to create the desired B-Pillar Plastic Component, We'll use that Master Section by extracting the lines as shown below and create a Bisecting Line with respect to those extracted lines to create our Main Tooling Axis.

DRAFT ANALYSIS ON THE CLASS A SURFACE:

Next, We will perform a Draft Analysis on the Class A Surface itself:

Before starting with a Draft Analysis Operation, we will go to the 'Customize View Parameters' option under the 'View Toolbar'. Then we will enter the 'Customize View Mode' where we will go under the 'Mesh' option and select 'Material' and press 'OK'.

To start the Draft Analysis in the 'Generative Surface Design Workbench', we will go to 'Insert' and then look for the option called 'Analysis'. Once found, we will go under that and click on 'Feature Draft Analysis. This will open the 'Draft Analysis' Dialogue box. There, we will ensure that under 'Mode' we have selected 'Quick Analysis', under 'Display' we will select 'Show or Hide the Color Scale' and then select '3 Degrees' as the permissible draft angle. Then, under 'Direction' we will choose the icon with the symbol of the compass on it which stands for 'Use the Compass to define the new current draft direction'.

It is evident from the above image that the Draft-Analysis on our Class A Surface was successful and the component is feasible to manufacture.

PROCEDURE TO CREATE THE CLASS B SURFACE:

Offset the class a surface 2.5mm directly.

Created boundaries so that we can extrapolate the surfaces.

After extrapolating the surfaces we have got the B Surface

PROCEDURE TO CREATE THE CLASS C SURFACE:

To create the Class C surface firstly we have to unhide the Class A Surface and extract its boundaries.
Then we're going to use the 'Sweep' command with 'Reference Surface' & 'With Draft Direction' to create the Class C Surface as shown below:

CREATED C SURFACE:

CREATED A + C SURFACE:

Join the class-A and class-C surfaces together

Trim the class-B surface with the join created earlier so that we can get closed body

Now if we want to create any boundary we can see that we can't create any boundary as it is a closed surface. so that means we have successfully created closed surface.