Challenge

Design of backdoor

HHimanshu Sharma21 Nov 2022

Aim

To Design Back Door using given Styling Surface.

Introduction

The backdoor or tailgate is the rearmost part of the automobile which opens upwards, downwards, and sideways to give access to the luggage space or seating. In most automobiles, the backdoor opens upwards. It is hinged to the roof and a gas stay support fixed at the body side outer for keeping the backdoor in the open position.

The material used in making the backdoor of the car is mainly steel but nowadays Aluminium is also used in making the panels.

The main advantage of Aluminium is that the density of Aluminium is very less as compared to steel so it reduces the overall weight of the car. But Aluminium is more costly as compared to steel.

TYPES OF DOOR OPENING:

Top-mounted door
Side-mounted door
Bottom Door

Different processes used for manufacturing the Back Door

Deep Drawing:

The metal deep drawing process is an effective method of manufacturing cups, cans, and other similar deep drawing products. The deep drawings having 2 main categories.

First-stage drawing: The blank shape of metal is placed on the die and in contact with the punch. When the metal specimen is a flat piece of sheet metal is used in forming and finish the product. Initially, the punch moves in a downward direction. The outer rim of the blank is subjected to pure radial drawing (drawing toward vertical axes) between the die and blank metal. The metal becomes a bend and slides over the die and is also stretched between die and punch. The metal in the vicinity of the punch head and contact with it bend and slide over the radii and stretch over the punch head.
Redrawing: The components drawn from the first stage again it is redrawn convert into more depth to form a cup shape in the die and punch. The second stage of drawing is called redrawing.

Fig.2. Process of deep drawing

Hemming

The inner & outer panels are joined by the process of hemming.

Hemming is a forming operation in which the edges of the sheet are folded over other parts in order to achieve a tight fit. Usually, hemming operations are used to connect parts together, to improve the appearance of a part, and to reinforce part edges.

In car part production, hemming is used in assembly as a secondary operation after deep drawing, trimming & flanging operations to join two sheet metal parts together. Typical parts for this type of assembly are hoods, doors, trunk lids & fenders.

The accuracy of the hemming operation is very important since it affects the appearance of the surface & surface quality. Material deformations, which occur while the hemming process, can lead to dimensional variations & other defects in parts. Typical hemming defects are splits and wrinkles in the flange, material overlaps in the corner areas. So it is very important to use simulation software tools to better understand the hemming process and minimize the number of “trial & error” during the tryout.

There are different types of hemming operations:

Conventional die hemming

In conventional die hemming, the flange is folded over the total length with a hemming tool.

Roll Hemming

In roll hemming, the hemming roller is guided by an industrial robot to make the flange.

COMPONENTS OF BACKDOOR:

Inner panel
Outer panel
Hinge reinforcement
Gas stays reinforcement
Wiper motor reinforcement
Latch & striker reinforcement

DESIGN CONSIDERATION OF A BACKDOOR:

Functional Requirement of Hinge and gas stay
Rear visibility criteria
Luggage volume area
Crash Analysis
Bend Test, Dent Test, Torsion Test & Endurance Test
Rear Crash Regulation
Gap and flushness Requirements

DESIGN OF BACKDOOR

The Outer Panel is the styling surface of the back door design. Other components of the backdoor are designed with reference to the outer panel surface. It acts as the outer cover & deals with the aesthetics of the car.

In this design outer panel is divided into two-part.