Design of backdoor

AIM:

To design the back door of the automobile vechicle (or) car and to create the outer panal,inner panal and reinforcement.

Software:

i used the NX CAD software 12.0.1 to create the sheetmetal of the component.

Introduction:

The door or opening of a cargo area may be hinged at the top, side, or bottom.If the door is hinged at the bottom it is called a tailgate, particularly in the United States. They are used on station wagons and pickup trucks as well as on some (SUV).Traditional drop-down station wagon and pickup tailgates can also serve as a mount for a workbench.Traditional U.S. station wagons included a roll-down window retracting into the tailgate to load small items or to allow the tailgate to be opened down on its bottom-mounted hinges. Because of the potential for carbon-monoxide fumes, the tailgate window on station wagons should be closed whenever the engine is running.Two-way station wagon tailgates may be hinged at the side and the bottom so they can be opened sideways like a regular door, or drop downwards as load platform extenders. They are designed with special handle(s) for opening in the selected direction on special hinges after the window is lowered.A three-way design that was also used by Ford allows for the tailgate to be opened like a door with the window up.General Motors developed a clam shell style "disappearing" design where the rear window rolls up into the roof and the tailgate slides down and beneath the load floor.If the door is hinged at the top it is termed a hatch, and is used on a hatchback.A bottom opening door is now common on Suvs.

Types of doors used in auto mobile vechiles:

they are three types of tailgate used in automobile vechiles they are,

• TOP MOUNTED
• SIDE MOUNTED
• BOTTOM MOUNTED

TOP MOUNTED:

This type of back doors are used for to get the better rear visibilitry compared to the other types of doors and today's modern cars we are using the top mounted doors. thi swill be use for the station wagon and suv's.

SIDE MOUNTED:

IT is generally used fo the suv's and muv's like the van type of cars they are used thbis type of doors. These doors are generally small in size and can be easily accessed. These doors are more convenient for the goods handlers carrying lengthy objects, long pipes where one door is kept open. so it is used to load and unload purpose it will be more convinient.

BOTTOM MOUNTING:

Bottom type or split type backdoor system is used in estate type cars, pickup trucks and some luxury SUVs. it is more convinient and convertible back door and it is a strong door if a person stand on the top of the door it will not happen any thing to that door.some time it will be dinning table for the tour persons so it is uses lot of ways.

They are two types of operated doors used in automobiles comodities they are

• Gas stay doors
• Electrical doors

the main purpose of these mechanisims is to open the back door without heavy efforts, because the backdoor have different parts and the weight of the back door is high, so we are not able to open the back door manually, so we introduced these two types comodities. and these also decides the premium of the car, mostly the electrically operated used in premium cars so we can buy the premium car it will be used the button to close the back door that is electrical doors and normal cars they are used the gas stay to lift the car door.

Gas stay doors:

ELECTRICAL DOORS:

BACK DOOR ASSY(ASSEMBLY) and MATERIAL SELECTION:

back door is not an one component they are many component inside the back door they are

• outer panal
• inner panal
• latch and striker reinforcement
• hinge reinforcement
• gas stay reinforcement
• wiper motor reinforcement

to create the the all component in single body it saves lot of time but the weight of the car will get so heavier if they are over weight acr it will not give us mileage so that's the main reason they used aluminium instead of steel it is stronger and it is light in weight and to create the each and every part weight less it will creates the big achievement for the mileage. Another aspect to be noted is that, if casted Aluminum parts are used instead of deep drawn steel parts there is no need of reinforcements and the overall weight of the car is reduced by approximately 5-10kg thus increasing the performance of the vehicle. Also the draft angle for casted parts is around 3 degrees while for deep drawn parts is around 7-10 degrees which helps in increasing the boot space.

LOAD CASES:

Different types of load cases on the back door of a car are as illustrated in the image so we have to consider all the mentioned criterias in our design.

PUNCHING:

Sheet metal punching is a cutting process in which material is removed from a piece of sheet metal by applying a great enough shearing force. CNC Punching can be used to produce holes and cutouts of various shapes and sizes.

WHAT IS EMBOSSES?

Embossing is a metal forming process for producing raised or sunken designs or relief in sheet materials by means of matched male and female roller dies, theoretically  with no change in metal thickness or by-passing sheet or a strip of metal between rolls of the desired pattern. they are some types of metals used in embosses they are

• zinc 
• copper
• galvanized steel
• cool rolled steel
• aluminium alloys
• steel alloys

Outer panal:
This panal is called as the class A surface this is the customer view point while buy a car so to provide some multiple coatings to strengthen the component from rust and scratch. 

HEMMING PROCESS:

it is process of to bend the two similar sheet metals to bend the top sheetmetal into the bottom sheet by bending to the distance of 0.2mm gap for the glue or rubber sealent to roll that component buy the use of roller to do the hemming process.

Hemming relief:

to provided the hemming relief to some corners because to not provide this type of reliefs the panel should spring back to original formation after roller is removed so thats the reason to provide hemming relief's.

Inner panal:

inner panal is main part in back door assemble because the most of the components will get fitted on this region only. It provides strength and helps in dissipation of forces outside the part with the help of embosses made on it. It helps in mounting some accessories.

Tooling axis:

this the kind of middle line it is used for  to manufacturing the material.it is used for to create the law extension command and it is used for the draft analysis also.

Sealing Flange:

 Its design is important as it decides how a backdoor is mounted on the rear body side of the car.It is that section of the inner panel which enables the backdoor to sit over the rear body side of the car. 

Reinforcement:

reinforcement means to making something stronger to the material they are lot of reinforcement used for back door they are

Hinge Reinforcement:

Gas stay reinforcement:

Wiper motor reinforcement:

striker and latch reinforcement:

Latch Trajectory:

Backdoor is the swinging part which rotates about hinge axis.  The position and orientation of latch striker is important for proper opening and closing of the backdoor. The positioning is done by sketching a circle with center as the axis of the hinge which passes through the striker at appropriate position with respect to inner panel. 

Draft analysis:

The Draft Analysis command enables you to detect if the part you drafted will be easily removed.

Final output:

Conclusion:

Thus the designing of the Back Door  is done as per Industrial standards and Manufacturing Techniques followed the guide lines to create the final back door.