AIM:

Design a back door using appropriate design methodology with provided input styling surface and intent necessary reinforcements and embosses.

Input styling surface:

input is provided with two panels upper half and lower half and those two panel are considered as inputs for creating inner and outer panel of the back door. 

• backdoor outer upper panel

• backdoor outer lower panel

Back Door:

A tailgate, or sometimes the hatch, is a hinged board or door at the rear of a vehicle that can be moved up or down during loading and unloading. Also called a tailboard, it is commonly found in pickup trucks or hatchback vehicles.

components of the Back door:

• backdoor outer upper panel
• backdoor outer lower panel
• backdoor inner panel
• mastic flange
• hinge reinforcement
• gas stay reinforcement 
• latch and striker mounts
• wiper reinforcement

Door Panel:

As you can see the input styling surfaces which are provided are not smooth and as some sharp edges on it.Appropriate changes are made on the outer lower and upper panel.  

the sharp surfaces are replace with blends and multi section surface. to provide a good styling surface.

upper door panel:

same procedure is followed for lower door panel where both are separately constructed using trim and edgefillets.

Lower door panel:

panels are constructed separately and named as backdoor upper and lower outer panel.

Backdoor upper and lower outer panel.

 inner panel:

The Back Door requires good rigidity, outer plate and inner plate, the inner plate have reinforced ribs. The back door panel side to inlay rubber sealing strip, around a circle with waterproof and dustproof. Luggage lid open support a general use cusp and four-bar hinge, hinge with balance spring, make it easy to open and close lid, and can be fixed in the open position, easy to take the goods.

After creating the outer panel take reference for inner panel and create a tooling axis for the elements.

from the reference surface offset create inner upper and lower panel and repair the surface to provide a smooth finish.

the offset for inner panel is consider according to the design parameters . the offset value 1.7 mm is thickness of panels in opposite direction for welding with 0.2 gap and thickness of panel with 0.75mm.

sealing flange:

Sealing flange area is where rubber material that seals the edges of your vehicle's doors, windows, windshield and other areas.they prevent outside elements such as rain, snow, wind and pests from reaching the inside of your vehicle and they are air sealed also.

sealing flange is stamped in the inner panel with appropriate depth that precise fit with inner panel.the Operation which are undergone to create sealing flange are sweep,join and split and parallel curve.

sealing flange base cut out with offset from inner panel and parallel curve from edges of inner panel.

then sweep operation is create withe sealing flange base . the height from the inner panel and sealing flange base id 25mm.

after sweep fillets are provided.

Mastic flange:

Mastic flange is created by cutting out the material in inner panel with appropriate design methodology.then flange is bended into back door outer panel with appropriate mastic relief of 5mm.

after creating the edges of sealing flange stamping follow the appropriate attachment for inner panel.

inner panel attachment with edges of sealing flange with sweeps and multisection surface.

A smooth inner panel with appropriate sealing flange at edge of panel is created for required design methodology.after the inner panel creation mastic cutout region is provided with appropriate reliefs.

the mastic region is created with flange to bend with outer panel.futhermore mastic relief gap is provided between the flange and outer panel.

Hinge placement:

Hinge needs a flat surface on inner panel to mount with fasteners.So flate surface are created on the inner panel with the appropriate design parameter values.

before that panel created with hinge mounting they are provided with certain embosses and cutouts on mastic region.

embosses and cutouts:

Embosses are created to increase the stiffness of the inner panel with durability to withstand the load on the panel. embosses are creating with certain depth using deep drawing machines. cutouts are provided on the embosses to distribute the load around the panel.

hinge mounting flat surface are created at top of a panel with blend corners.

at the hinge mounting gas stay fastners are provided with appropriate placements.

gas stay:

In the most of the cars, these back door are operated with the help of gas stay which in turn reduces the effort required to lift the door. Some luxuary cars have powerd backdoor which in turn is driven by an electric motor.

so appropriate reliefs(holes) are provided to the inner panel.

again the cutouts on embosses are provided for load distribution throughtout panel.

latch and striker mounting:

latch and striker are mounted on panel according to the trajectory angle. so the sketch is position on the along the plane created on bottom side of the panel.

trajectory will decide the position of latch. according to it do the required cutouts and flanges on the inner panel.

latch mounting surface should be flat and appropriate cutout for fastners are provided with required tolerance.

wiper mounting:

Wiper placing surface should be flat and required flatness on surface is provided.

In this design ,the model is made on one side the other is symmtery. 

In-addition reinforcements are provided for panel with sufficient stiffness. then panel are undergone drafting analysis.drafting for inner, outer and reinforcements used with appropriate design angle of 7 deg.

Draft analysis :

Inner panel:

Outer panel :

reinforcement:

Hemming:

Hemming is a process by which that edge is bent. It gives a neat and a compact joint. However, it is less strong than a welded joint. so hemming is hemmed with the inner panel with design values with thickness of surface.

Hemming on outer upper half of panel:

hemming is made with tritangent fillet

Hemming on outer Lower half of panel:

solidparts of panels and reinforcements:

Inner panel:

outer panel:

inner panel with reinforcement:

Relief on outer panel is provided:

Relief are given at the corners to cut unwanted material why distrubing the roller mechanisms while manufacturing the hemming process.

final body:

Design parameter after thickness: