Week 9 - Challenge 3 - Bumper

BUMPER DESIGN

AIM

Create the Bumper Plastic component by the given Class-A surface. To begin with, the tooling axis for the given Class-A Surface might be created meeting the requirements of the draft angle and at the end perform the Draft analysis on the model.

INTRODUCTION

A bumper is a structure attached to or integrated with the front and rear ends of a automobile, to absorb impact in a minor collision, ideally minimizing repair costs.They are designed to absorb impact onto the front and rear of vehicles and minimize low-speed collision damage.

DESIGN PROCESS

CLASS A SURFACE

Class-A surface means aesthetic 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.

The first step is to check the continuity of the class A surface. This is to ensure that there is no gap between surfaces. If we find any then we should fix that first.

Inorder to check the continuity of the class A surface we can use the join or boundary command. If it shows no open boundary the we can proceed to next step.

CREATION OF TOOLING AXIS

Tooling axis represents the opening and closing of the mold core and cavity during the manufacturing of the components. A plastic product designer should consider the best tooling direction to cutdown the cost of the component very less.

• Check the best tooling direction for the given surface.
• We can find out the best tooling direction by cross checking all the three axes.
• Here we can find out that the best tooling direction for the pumper class-A surface is along x-axis direction
• The method I choose to create the tooling axis is first extracted a surface and create a midpoint on that surface. The introduced an axis system on that point.
• Then created a line through the point direction along x axis.

SURFACE B 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.

• Offset the class-A surface to 3mm inward direction.
• Rework on the patches and discontinuity of the offset surfaces using the features like extract, multi-extract, sweep, multi-section surfaces, extrapolate.
• To ensure the continuity of the Class-B surfaces check the boundary command to find out the boundary.
• Hence class-B surface creation is done.

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.

Since it is a complex class-A surface, we cannot simply create the class-A boundary curve and sweep it at one shot. Hence, we need to create smaller curves using multi-extract command and then create sweep of 90 degree with reference to the surface option. sweeps at the midportion of the bumper  should have a 93 degree value to pass the draft analysis.

• Extrapolate and trim off the sweep surface corners at the required edges.
• Join the sweeps using the join command and the class-c surface is created.

CREATING THE FINAL SURFACE

• First step is to join the CLASS-A surface with CLASS-C surface.

• Then Trim the Joined surface with CLASS-B surface to achieve the final Bumper surface.

• Then went to part design work bench and using the close surface command create the base bracket solid part body.

3D Part model in various orientations (Isometric, Front, Side, and Top View)  

Draft analysis of the Final part body

Same procedure for the draft analysis of CLASS-A surface is followed.

• Change the view mode to material shading
• Align the Compass with Tooling axis.
• Lock the draft direction and perform the Draft analysis.

Conclusion

I have successfully created the class-B and Class-C surfaces of Bumper using the given Class-A surface along with the tooling axis in the CATIA surface workbench.