Week 8 - Challenge 4 - Bumper

BUMBER:

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 both the manufacturing and bumper repair process.

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

OBJECTIVE:

The main objective of this challenge is to create a solid body of 'Bumper' with the help of the closed surface method by using the 'Generative shape design' workbench in CATIA V5. Performing the 'Draft Analysis' on the solid part body of the Bumper.

PROCEDURE:

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.

Method for creating 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 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 with the point and direction along x axis. Here both the outer flanges have 5.1-degree draft with respect to the axis created. Hence going with the axis created will not make any difficulties during the draft analysis.

Another method is by creating intersection along y direction. And then create lines on the walls and then create a bisecting line with the lines on the wall and point created earlier. We will get an axis which will satisfy the draft analysis requirement.

draft analysis:

The Draft Analysis is a command enables you to detect if the part you drafted will be easily removed. This type of analysis is performed based on colour ranges identifying zones on the analysed 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 are as follows

Change the view mode of the component to be in customized parameter mode and then select the shading mode as materials.

Then click on 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 colour 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 much draft on specific points when we move the cursor point.

CLASS B SURFACE:

To create the class B surface, offset the class A surface inside as per our thickness requirement (here the thickness is 3mm,so I offset the class A to 3mm inside).

we can spilt the body into 4 seperated section surface,

then extrapolate the individual surface and trim them in to the requried lengeth

then give the fillets in the each edges.

CLASS C SURFACE:

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 vaue to pass the draft analysis.

then use sweep command in the boundary line

FINAL TRIM OPERATION

first we have to join the class a syrface and class c surface

then trim the joint into class b surface and we have the final closed output surface

then we have to create the surface into solid part. go to part surface and thicken it

DRAFT ANALYSIS FOR THE SOLID SURFACE:

TREE STRUCTURE:

3d VISUALS:

CONCLUTION:

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.