Week 9 - Project - Master Section Development

B-PILLAR DESIGN

Objective: To design a B-Pillar along with the Attachment Features following the master section and Class-A meeting all the design requirements.

Introduction:

Class A Surface:

In automotive design, a class A surface is any of a set of freeform surfaces of high efficiency and quality. Although, strictly, it is nothing more than saying the surfaces have curvature and tangency alignment to ideal aesthetical reflection quality, many people interpret class A surfaces to have G2 (or even G3) curvature continuity to one another.

Class A surfacing is done using computer-aided industrial design applications. Class A surface modellers are also called ‘digital sculptures’ in the industry. Industrial designers develop their design styling through the A surface, the physical surface the end user can feel, touch, see etc.

Class B Surface:

Class B Surface is a surface below a certain thickness from a Class A Surface. We can also say that it is an engineering surface because it contains all the engineering aspects of the model which is required.

Class C Surface:

Class C Surface is a surface that joins the Class A Surface with Class B Surface.

Tooling Axis:

Tooling axis is the direction in which the mold or core and cavity opens.

Draft:

Draft is the angle in which the part is tapered to allow it to release. As the part cools, it tends to shrink to the core side of the mold. Draft is required on all parts in the direction of mold movement in order to allow parts to release or eject from the mold properly.

Most parts or applications require a minimum of 0.5 to 1 degree, however 3 degree is widely accepted as normal.

Procedure:

Importing Class A Surface:

First of all we have to import the class A Surface into the Catia V5 Software.

Continuity Check:

After getting the Class A Surface from the styling team, we have to ensure that the Class a Surface is properly joined and has no discontinuity on it. To check that we have to use the Boundary command or Join command.

Creation of Tooling Axis:

First of all, we have to analyse manually or visually to see which direction is the most appropriate for tooling axis. After analysing we found that in y-direction, it is easily tooled.

Bisecting line Method:

In this Class-A surface we have given with the master section also. So, we use that master section and create a tooling axis using bisecting line method. For that, we extract the master section and create a point between the extract.

Then we create a bisecting line between two extract and again for the other two.

After that, we again create a bisection between the lines created earlier.

This line is our final tooling axis.

Draft Analysis of Class A Surface:

First of all we should change the view to the Customize View parameters and then select the material mode and the ok. After that we will open draft analysis command and then click on the compass icon and then align the compass of the window with the tooling axis earlier created and then lock the draft direction. After that click on the surface and see that the surface is within permissible limit of the draft value. The surface should be green and in the column 3 degree should be inserted. Here, we find that there are some patches which are not clearing the draft. So, firstly we have to contact with the styling team and get the surface resolved. But for now, we can proceed here.

Creation of Flanges:

Here we found that, the master section is extended beyond the Class-A. So, we have to create flanges on both sides.

We created both the flanges using sweep command.

After, that we trimmed the Class-a with the flanges.

Then the both edges are filleted and we got Class-A surface with Flange.

Creation of Class B Surface:

First of all, we have to find out the thickness of the component. So, we measure the master section. Here, we found the thickness of the component to be 2 mm.

So, we offset the Class-A with flange by 2 mm in upward direction. After that we got a Class-B with flange.

Creation of Class C Surface:

First of all, we create an extract of the edge and then do sweep with 3 degree draft facing outward.

Then we repeat the same for the remaining edges wherever possible.

In the remaining portions we create separate sweep in plane area and then do multi-section and join them.

After that we extrapolate the back portion of the sweep.

After that we extrapolate and trim the sweep created earlier. This is our Class-C surface with A-surface.

Solid Body Formation:

After that we extrapolate further the Class-B and then trim this extrapolate with Class-A and Class-C surface to get a closed surface.

Go to the part workbench and close the part using close surface option.

Creation of Attachment Features:

1.Creation of Dog House:

First of all, we have created a point and a plane on the master section and then created a sketch on it taking the reference from the master section.

After that the sketch is extruded.

For the other side, a plane is created and then a sketch is drawn following the next master section.

Then the sketch is extracted for extrude.

The extrude is extrapolated and then back side is trimmed off.

Then the surface is thickened by 2 mm in outward direction and the front part is split.

The inner wall should be drafted. For that a lifter axis is created and then drafted.

Provision of sink mark:

The inner wall is offset to 1.2 mm so that we can have 40 % of the thickness.

Then the B-Surface is also offset to 3 mm.

Here we create an intersection so that we can get a reference line and create sketch using that line.

After that the sketch is extruded, trimmed and then the part is split.

Then the split body is drafted and filleted.

2.Creation of 4-Way locator:

Taking the reference of the master sections a sketch is created.

The sketch is then pad, chamfered and drafted.

Then it is added to the dog house and filleted.

Finally, the dog house along with the locator is then union trimmed with the B-Pillar body.

Now, for creating locator on the other side we create a point and a plane between the master section and do symmetry.

3.Creation of Ribs:

First of all, we create a sketch on the plane created earlier.

Then the sketch is extracted and extruded.

After that the surface is thickened by 0.8 mm.

Then the B-Surface is extracted and offset by 10 mm upward.

Then the body is split and same for the backside but with class-A.

The body is then drafted.

Do same for the other Ribs also and the union trim with the main body.

At last fillet is added to them.

Draft analysis is done in order to detect if the part that has been drafted will be easily removed or not. This type of analysis is performed based on the colour ranges identifying zones on the analyzed elements where the deviation from the draft direction at any point corresponds to the specified values. When the draft analysis passes, it means our part is easily toolable or can be easily ejected.

For this, we have to change the view parameter to material mode and then perform draft analysis.

Tree Structure:

Conclusion:

From the given Class A Surface, Class B Surface and Class C Surface were created to form a solid model and then attachment features were also added. at last draft analysis was done along with the tooling axis meeting the requirement of draft angle.