Week 8 - Challenge 4 - Bumper

AIM

Create the Bumper Plastic component through the given Class-A surface. To begin with, the tooling axis for the given Class-A Surface should be created meeting the draft angle requirements and performing the draft analysis on the model at the end.

INTRODUCTION

A bumper is a structure attached to or integrated with the front and rear ends of a motor vehicle, to absorb impact in a minor collision, ideally minimizing repair costs.

They are designed to absorb impact to the front and rear of vehicles and minimize low-speed collision damage. Today, standard passenger vehicle bumpers have a rigid reinforcing bar under the outer cover, with sections of compressible foam or plastic underneath.

A bumper is made up of four parts:

• Bumper cover.
• The bumper absorber.
• The bumper reinforcement bar.
• The bumper mounting system.

The first car bumpers were created all the way back in 1901 and consisted of metal beams attached to the front and rear of the car to protect it during a low-speed collision. Designed to protect the expensive and fragile components like the headlights, tail lights, hood, exhaust, and cooling systems, early metal bumpers were focused on sheer resilience.

Modern consumer production cars have almost completely switched over to plastic bumpers. Modern car bumpers are made from thermoplastic olefins, a blend of plastic molecules, rubber, and a reinforcing filler like carbon fiber or calcium carbonate. This blend of materials creates a scratch and impact-resistant plastic that can bond with a wide range of paints and finishes, making it ideal for vehicle bumpers.

Plastic is the preferred material for modern car bumpers for several reasons. First and foremost, plastic is much lighter and more aerodynamic than metal, which improves the car's fuel efficiency. Plastic is also easier to shape, which is useful during manufacturing and bumper repairs.

Bumpers of most modern automobiles have been made of a combination of polycarbonate (PC) and acrylonitrile butadiene styrene (ABS) called PC/ABS.

OBJECTIVE

• To design Bumper as per automotive industry Standard.
• Create a tooling axis for the given CLASS-A surface.
• Create B Class and C Class surfaces
• Create the final surface model and convert it into a solid body using the close surface command in the part design workbench.
• Perform draft analysis for both Class-A surface and Final part body.

DESIGN METHODOLOGY

Skin data would be provided to us by the styling teas.

Class-A surface means visible 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.

Class-A continuity check

Analyse the class A surface through visual inspection.

To make sure that the given surface has no gap between them. We can check it also with the help of Join or boundary commands.

Procedure for creating the 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 cut down the cost of the component very less.

Method opted for creating a tooling axis for the bumper

• Check the best tooling direction for the given surface.
• We can find out the best tooling direction by cross-checking all three axes.
• Here we can find out that the best tooling direction for the pumper class-A surface is along the x-axis direction
• The method I choose to create the tooling axis is first extracting a surface and creating a midpoint on that surface. They introduced an axis system at that point.
• Then created a with the point and direction along-axis.
• Here both the outer flanges have a 5.1-degree draft concerning the axis created. Hence going with the axis created will not make any difficulties during the draft analysis.
• Another method is by creating an intersection along the y direction. And then create lines on the walls and then create a bisecting line with the lines on the wall and the point created earlier. We will get an axis that will satisfy the draft analysis requirement.

Draft analysis for the given CLASS-A surface

The Draft Analysis is a command that enables you to detect if the part you drafted will be easily removed. This type of analysis is performed based on color ranges identifying zones on the analyzed element where the deviation from the draft direction at any point, corresponds to specified values.

Draft analysis is done after determining the tooling axis, draft analysis is used to check whether the minimum draft (3 degrees) is maintained or not.

• Procedure for performing the draft analysis is as follows
• Change the view mode of the component to be in customized parameter mode and then select the shading mode as materials.

• Then open the featured draft analysis tool from the insert menu.

• Then click on the use the compass to define the current drafting direction and then drag and align the compass on the Tooling axis.

• Then lock the draft direction and perform draft analysis by clicking on the component.

• The green color shows the positive daft tooling direction and the given surface passes the draft analysis.
• Click on the analyses under the running point to check the draft analysis on the individual faces. It shows how many drafts are on specific points when we move the cursor point.

SURFACE-B CREATION

Class-B surface means the thickness of a part is not visible and is inside the part. In other words, the Class-B surface is a surface below a certain thickness from the class-A surface. This is the surface that contains the engineering aspects of a model.

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

SURFACE-C Creation

Surface that joins class-A and class-B surfaces are 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 in one shot. Hence, we need to create smaller curves using the multi-extract command and then create a sweep of 90 degrees concerning the surface option. To pass the draft analysis, sweeps at the midportion of the bumper should have a 93-degree value.

• Join the sweeps using the join command and the class-c surface is created.

Creating the final surface of the Bumper

• First step is to join the CLASS-A surface with the CLASS-C surface.
• Then Trim the Joined surface with CLASS-B surface to achieve the final Bumper surface.

Go to the part design workbench 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)

Conclusion : The Bumper is created with considering all Design Methodology