Week 9 - Challenge 3 - Bumper

BUMPER  DESIGN  CHALLENGE

AIM

Create the Bumper Plastic component  from the given Class-A surface and  find the correct tooling axis and create the draft analysis to check whether the part is manufacturable.

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.

A bumper is a structure attached to or integrated with the front and rear ends of a vehicle to absorb impact in a minor collision, ideally minimizing repair costs. Stiff metal bumpers appeared on automobiles as early as 1904 that had a mainly ornamental function. Many developments in materials and technologies, as well as greater focus on functionality for protecting vehicle components and improving safety have changed bumpers over the years.Pedestrian safety  is also major need for bumber.

CLASS  A SURFACE 

In automotive design application THE  Class A Surfaces are created on all visible exterior surfaces.It is the part with asthetic fearures  (ex; body panels, bumper, grill, lights etc.) and all visible surfaces of see-touch & feel parts in interior (ex: Dashboard, seats, door pads etc.).This surface has 0 mm thickness.

 Fig 1 Bumber Class A Surface

 Fig 2 Bumber Class A Surface

Next is the most important step in this process 

FINDING TOOLING AXIS

 Tooling axis or tooling direction is main consideration for plastic part and mold parts because it defines movement of mold part and possibility of plastic part to come-out from mold part (Core and Cavity).

So we need to align the part in different directions and check whether the part is completely visible. Try it in X Y and Z directions.So we find the X axis to be better. THen fix X asis as tooling axis .

We tentatively draw a point and line from it from the surface,and draft analysis is done on the part.

 Fig 3 Tooling axis for Class A Surface

DRAFT ANALYSIS 

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.

The Draft Analysis allows to easily analyze a part for proper draft angle and whether it is manufacturable or not.

Here the part have passed the analysis because it is having minimum draft angle of 3 degree 

 Fig 4 Draft analysis  for Class A Surface.

CONSTRUCTION OF CLASS B SURFACE 

 In this challenge we are using another method for creating class b sufrace from the class a surface.The surface of the bumber is a complex sufrace with fillets and irregular surface.

So we will be moving with another method.Here  direct offset method is used.The class A surface is directly offsetted. So we  will be getting a surface with some patches unfilled.

The surface is then repaired by splitting the surface into two and the working on the patches by extracting it and extrapolating it and making intersections and then trimming the surface. Then proper fillets are provided.

The steps used are 

• extract the surface
• extrapolate the surface and  make intersection
• Trim the surface and fillet it.

 Fig 5 Offseted surface to make class B surface

  Fig 6 Class B surface repaired for patches

  Fig 7  Final Class B surface repaired.

 CONSTRUCTION OF CLASS C SURFACE 

C surface is the surface  that joins class-A and class-B surfaces. Class C is often specified for interior surfaces not readily visible.

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 .

We need to provide sweep command seperately for the  surfaces.

The sweep provided will be two types

• Using drafting direction
• Using referencr surface 

We need to use drafting direction when the surface is perpendicular to tooling direction. 

We need to use reference surface when the surface is parallel to tooling direction.

To check it, we need to just extrapolate and check with the tooling axis.

  Fig 8 Sweep for surface 1

  Fig 9 Sweep for surface 2

  Fig 10 Sweep for surface 3

  Fig 11 Sweep for surface 4

  Fig 12 Sweep for surface 5

The sweep surface length is increased so that proper intersection is made  is trimmed to form a single surface  and joined with the class A surface

  Fig 13 Sweep surface 

  Fig 13  Sweep for surface joined 

  Fig 13 Sweep for surface joined with Class A 

Then the final trim is created by trimming joined surface with class B surface.

  Fig 14  Final trim surface 

  Fig 15  Final trim surface 

  Fig 16  Final trim surface 

Then the part is converted to a closed surface by using closed surface from the part workbench

  Fig 17  Closed body surface surface 

DRAFT ANALYSIS 

Draft analysis is used to check whether the product is manufacturablr or not.and also to check the draft angle of the surface.

The minimum recomended angle is 3 degree.

Here the surface passes the test with 3 degree ,but the  2.5 degree is taken to aviod the failing of surface in c surface.

Fig 18 Draft analysis of  Closed body surface 

Fig 19 Draft analysis of  Closed body surface 

Fig 20 Draft analysis of  Closed body surface 

TREE STRUCTURE 

Tress sturcture of the  part is shown below 

Fig 21  Tree structure of the bumber part 

Fig 22  Tree structure of the bumber part 

Fig 23  Tree structure of the bumber part 

Fig 24  Tree structure of the bumber part 

Fig 25  Tree structure of the bumber part 

Fig 26  Tree structure of the bumber part 

Fig 27 Tree structure of the bumber part