Roof Design

 Aim: 

For the Given Roof surface, Develop the essential flanges and reinforcements such as front rear centre and bow rail roofs. 

 

Introduction:The roof is an important part of the car body that is used to cover the car from the top. Because it is a class A surface, it must be visually appealing and attractive to the customer. It also protects the occupants and components inside the car from the sun heat, rain, dust, and other elements. 

                                                                                       

Front rail roof with thickness 0.75 mm toward outer roof

It provides support to the car's windshield glass. Spot welding is used to join one end to the windshield, and mastic is used to join the other end to the outer roof. The most bottom flange was placed by considering the visibility criteria. 

                                                                                                     

Rear rail roof with thickness 0.75mm towards the outer roof

This support is used to connect the back door and the outer and inner panels of the body side. Using spot welding, the backdoor was joined to it, and the other end of the rear rail was connected to the roof with mastic sealants. The most bottom flange was placed while keeping headroom clearance and rear visibility in mind.

 Bow rails roof from front with thickness 1mm towards outer roof.

Its purpose is to provide support for the outer roof. During the design process, the head room clearance and visibility criteria must be considered. Because it is a styling surface, only mastic sealants were used to join the bow rails and roof. More thickness and embossing can be added to the rails to increase their strength ang high moment of inertia value.

                                                                                             1st bow rail

                                                                                                        

                                                                                         2st Bow rail

                                                                                                         

                                                                                  Centr Bow rail 

 

Full assembly of the car roof

 

Ditch area and joining operation of the parts: 

It is the part of the outer roof that has been enlarged. Spot welding is used to attach the support, such as the rail and bow, to the ditch region. Because it is not a styling surface, spot welding was utilised on it. Except for the side connection (ditch area), all other connections are made with mastic. A 5mm space was provided between the outer roof and all supports for the mastic.

Draft Analysis

It must be done  for the smooth manufacturing process in particular direction i.e. normal to the surface. In this method, the draft angle will be checked. It must by more than 7 degree for positive draft. One should try to avoid the negative draft during the design stage. 

As one can see on the right side colour pattern green, yellow, blue and red. If the part have positive draft, it will present green colour otherwise blue or red. In the proceding,  the draft analysis was performed for all the parts of the roof.  

Note: In some portion, we can not avoid the negative draft. So bending operation used for the manufacturing process, because deep drawing can not be done at the negative draft area. 

Outer pannel

front rail roof

Rear roof rail

1st Bow rail roof

2nd bow rail roof

Centre bow rail roof

 Conclusion: The required roof design was completed based on the given surface, and all criteria were taken into account when designing the parts..