Week 9 - Project - Master Section Development
AIM:
To design a B pillar with the given mastersection to follow the design criteria and thickness and thereby devolop a closed volume part.
INTRODUCTION:
The B-pillar is the post between the front and back seat doors of a car, connecting the roof to the body. It can also be defined as the vertical roof support structure located between the front and rear doors on a typical vehicle. It corresponds with the A pillar located on either side of the windshield at the front of the car and the C pillar which sits on either side of the rear window on a typical sedan car.
MASTER SECTION:
Master sections are the guides for design requirements which decide the component packaging after technical (Styling, Concept or Class-A) surfaces. Following is the general workflow that is followed for the design and development of interior and exterior automotive trims in OEMs.
PROCEDURE:
1. After importing the model into Catia, check the given Class A surface for geometry errors or if the faces are missing, create a new face with the multi section tool available in Catia.
2. Inorder to provide the draft for the entire component, Tooling axis has to be created for the core and cavity to be designed in the later stages.
3. From the given mastersections, create the tooling axis with the bisecting line option available in the Line tool.
4. Next aim is to create the B surface which has to be created 2mm from the class A surface, which has to be an exact replica of the class A surface provided. Also flanges has to be created on either ends of A surface as well as B surface with reference from the mastersections given.
5. The general steps followed in creating a surface is by extracting the surfaces without fillets, untrim and extrapolate the extracted class A surface if needed and offset the surface to the part thickness given. Next step is to trim or split the surfaces acording to the shape needed.
6. After the B surface is generated, C surface has to be devoloped in the Class A surface using the Sweep toolbar without any generic change in class A with a minimum draft angle of 3 degree.{ Note only if Class C surface is in the direction of tooling axis}. All the draft angle has to be given outside of the part ie. the material has to be added rather than cutting it.
7. After the C surface is created all along the boundary of class A, join and trim it all together to make it as a single surface.
8. Now the class A and class C has to be trimmed to form as a single surface and there after trim it with the above devoloped Class B surface in order to get the B pillar part.
9. After which the part is created, check for the boundary if it is closed or not and now change the workbench to Part design and create a solid part out of it using the closed volume tool.
10. After the creation of closed body, check whether the main tooling is clearing all the part within the draft given. The draft analysis of teh B piller is given below:
DOG HOUSE WITH LOCATOR AND RIB CREATION:
1. For the Rib and Dog house, proper design rules or criterias has to be followed which are given below:
- Minimum height: Less than 6mm causes steel condition.
- 3:1 ratio of steel width to height. But 2:1 is preferred.
- Minimum width:3:1 ratio of steel width to height. But 2:1 is preferred.
- Draft: Minimum 1.5deg.
- Inorder to avoid sink marks : Height (C) = 40% of nominal thickness. Width (B) = 3.0mm-6.0mm.
- Optimal radius:25mm
2. After devoloping the dog house, the inside part will not be drafted with the main tooling axis, so that a side core axis or lifter axis has to be created and a seperate draft has to be given to the interior of the dog house. The four way locator can be easily devoloped with the reference from the sketch of mastersection and extrude with applying thickness to it. With applying proper chamfer, draft and fillet radius, locator can be crteated succesfully.
3. The draft analysis for the dog house is given below:
But the interior sides of dog house will be cleared only using the Lifter axis and draft analysis is shown below:
4. The ribs has to be created with 50mm apart on either side of the pillar to impart strength to the main part. The draft analysis for the ribs is given below:
TREE STRUCTURE:
PPT SS: