Design of backdoor

BACK DOOR DESIGN

AIM; The aim of this project is to design the back door of a car from the given styling surface by following the design rules and regulations.

OBJECTIVE

The main objective of the project is to design the back door of a car by following the industrial standards, and create the inner panel and also design the necessary reinforcement for improving the strength. And perform draft analysis on it to check whether it is manufacturable or not.

INTRODUCTION

BACK DOOR

An automobile back door is the panel that covers the boot or trunk of an automobile, it is also known as the tail gate. It ennables the access to the main luggage compartment. The back door is an assembly of many parts such as outer panel upper , outer panel lower , inner panel , Reinforcement. The joining operations of inner panel and outer panel take place in back door are by the process hemming and by using the mastic sealents.

Various types of back door are the following

• Top Mounted Door
• Side Mounted Door
• Bottom Mounted Door

PARTS OF A BACK DOOR OR TAIL GATE

• OUTER PANEL UPPER
• OUTER PANEL LOWER
• INNER PANEL
• HINGE REINFORCEMENT
• LATCH AND STRICKER REINFORCEMENT
• WIPER MOTOR REINFORCEMENT
• GAS STAY REINFORCEMNT

DESIGN CONSIDERATION

The following are the main design criteria considered while designing the back door

• Force Dissipation
• Latch And stricker placement and positioning
• Hinge positioning
• Gas stay positioning
• Material selection
• Hemming

FORCE DISSIPATION

The one of the main design consideration taken while design the backdoor is the force dissipation during an accident or any impact . For reducing the force reaches the inner cabin during an impact the V or Y embosses are created on the inner panel so that during an accident the force first reaches the embosses and shape of the embosses diver the force toward sideward or upwards instead of reaching it on the cabin. Here the emboses are created in such a way that to divert the force towards outside, as shown below.

MATERIAL SELECTION

The material selection also have an important role in determining the overall cost and weight of the back door. The commonly used materials are aluminium and steel.Comparitevely steel has higher weight than the aluminium since its density is high compared to aluminium but the cost of the steel is low when comparing it with aluminium for most of the low budget car steels are prefered. Nowadays most of the vehicle manufactures are switching to aluminum because of its advantages such as lowe weight we can create the complete inner panel of a backdoor as a single part if we use aluminium and thus we can reduce the weight of the car by a large extend and by this way we can improve its overall perfomance, aluminium parts are mainly created using the operation casting , but the steel parts are created by deep drawn method and in the case of aluminium we can give the draft angle about 3 deg and by this way we can increase the boot space of the car.

LATCH AND STRICKER POSITIONS

The latch and stricker poitioning is the another important design consideration , which has a major role in the opening and closing of the back door.

HEMMING

Hemming is the process in which the sheet metal edge is rolled into itself . hemming is the process in which the edge is rolled fkush to itself , the hemming is done on the outer and inner panel with a clearence of 0.2mm on the either sides, since in the corner the hemming is difficult to perform, reliefs are given at that portions.

REINFORCEMENTS

Reinforcements are used to increase the strength of the mountings so that there is no unnecessary dents or noise occurs at the time of motion, in this backdoor reinforcement are given in the following places, hinge reinfrocemnt, gas stay reinforcement, wipwer motor reinforcement, and latch and stricker reinforcemnt as shown below,

DIFFERENT TYPES OF SHEET METAL OPERATIONS IN THE BACK DOOR

• DEEP DRAWING
• EMBOSSING
• HEMMING
• BLANKING
• PUNCHING

DEEP DRAWING

The metal deep drawing process is an effective method of manufacturing cups , cans and other similar deep drawing products, there are two categories of deep drawing

• First stage drawing
• Redrawing

HEMMING

It is a forming operation in which the edges of the sheet are folded or folded over another part in order to achieve a tight fit, hemming are the joining operations which are done on the sheet metal , here for the joing of outer panel to inner panel hemming is used. the various types of hemming operations are the following

• conventional die hemming
• Roll hemming
• open hem
• closed hem

BLANKING

Blanking is a cutting operation of a flat metal sheet and article punched out is known as blank.

PUNCHING

It is a similar process like blanking it is used create the holes

EMBOSSING

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 by not changing the thickness.

BACK DOOR ASSEMBLY AND PARTS DESIGN

• OUTER PANEL

INNER PANEL

REINFORCEMENTS

DRAFT ANALYSIS

FINAL RESULT

CONCLUSION

BAXK DOOR OF A CAR IS CREATED BY FOLLOWING THE DESIGN CONSIDERATIONS AND DESIGN RULES AS PER INDUSTRIAL STANDARDS AND FINALLY DRAFT ANALYSIS IS ALSO CONDUCTED TO CHECK WHETHER IT IS SATISFYING THE MIN 7 DEG DRAFT ANGLE.