Challenge

Design of backdoor

NNumit Sharma23 Sept 2022

CAR BACK DOOR

AIM:

To design the back door of the car and make the inner panel for the back door and also design the necessary reinforcements.

INTRODUCTION:

The trunk (North American English) or boot (British English) of a car is the vehicle's main storage or cargo compartment, often a hatch at the rear of the vehicle. It is also called a tailgate. These doors can be operated manually or electric powered. In most luxury cars door is electrically operated. It involves a very major role during rear crash cases. so our design must obey crash requirements. the institute of highway safety analyses the different accidents and they set a test to rate our car. so these rating depends on the design of the trunk and material used, flanges, embosses, type of joining of the inner panel and outer panel, etc

Types of Doors based on working position:

Top Mounted Door
Side Mounted Door
Bottom Door

Top Mounted Door Side Mounted Door

The Back Door is operated By Two Types of condition

Electrically Operated
Gas Stay Powered

The main purpose of these mechanisms is to open the back door without heavy effort because the backdoor has different parts and the eight of the back door is high, so we are not able to open the back door manually, so we introduced these two electrically operated used in premium cars.

Gas Stay Powered Electrically Operated

Back Door Assembly:

Inner Panel
Outer Panel
Hinge and its Reinforcement
Wiper Motor Reinforcement
Latch & Stricker and Its Reinforcement
Gas Stay Reinforcement

The major problem with the Back door is material selection. mostly in the past days, steel is used, but it makes very problems the steel parts have a heavyweight, so it reduces the fuel economy, instead of steel presently in high-end cars aluminum is used, the main objective of aluminum it has less dense material and its suitable for complex shapes, and it also gives the thickness locally because it has done casting, in case of steel we used deep drawing operation. there are some advantages and disadvantages are there

so by using aluminum we can reduce the number of parts and assembly involvement. and it is a costly material.

Different types of Sheetmetal operations are done in 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 have two 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 finishing 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 also stretched between the die and punch. The metal in the vicinity of the punch head and contact with it bends and slides over radii and stretches over the punch head.
Redrawing: The components drawn from the first stage again it is redrawn and converted into more depth to form a cup shape in the die and punch. The second stage of drawing is called redrawing.

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 with no change in metal thickness or by-passing sheet or a strip of metal between rolls of the desired pattern. The metal sheet is drawn through the male and female roller dies producing a pattern or design on the metal sheet. Depending on the roller dies used, different patterns can be produced on the metal sheet.

Materials commonly used in the metal embossing process include:

Aluminum Alloys
Steel Alloys
Zinc
Copper
Galvanized Steel
Brass
Cold Rolled Steel

Hemming:

Hemming 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. Normally hemming operations are used to connect parts together, improve the appearance of a part, and reinforce part edges.

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

There are various types of hemming operations:

Conventional die hemming: In conventional die hemming, the flange is folded over the entire length with a hemming tool.
Roll hemming: In roll hemming, the hemming roller is guided by an industrial robot to form the flange.

Open Hem: A Hem has a full round feature and a return flange. In an open hem, the bend angle is equal to 180 degrees.
Teardrop Hem: In teardrop hem, the bend angle is greater than 180 degrees.
Closed Hem: Hems without any inside radius are called closed hems. Closed hems are not recommended if the hem geometry is to be painted or if the material used is SST or Aluminium

Blanking: Blanking is a cutting operation of a flat metal sheet and the article punched out is known as blank. Blank is the required product of the operation and the metal left behind is considered a waste.
Punching: It is similar to blanking only the main difference is that the hole is the required product and the material punched out from the hole is considered a waste.

Inputs for Designing of Backdoor:

Outer Panel - 0.75 mm
Inner Panel - 0.75 mm
Reinforcements - 1.5 mm

Class a Surface:

Backdoor outer upper and lower class surface has to be repaired according to the smoothness. After repairing the surfaces, the door is divided into two parts Door Outer Upper and Doo Lower Panel.

First, we need to create the Tooling direction for the Deep drawing operation. It shows that all the operations like embossing are done by considering this vector direction and it will help in manufacturing the part,

After that, we have to create Sealing Flange by offsetting the outer panel to a specific distance.

Then we will be creating the Back door inner panel flange by offsetting the outer surface at a distance considering the sheet thickness and thickening direction.

Then created the connecting flange to join the inner panel and sealing flange.

Then for the windshield panel mounting, the windshield panel is created and joined with a sealing flange

Now to assemble the back door with the vehicle Hinges are used to open and close the door. For that to increase the local area strength we have to design the emboss and provide the appropriate reinforcements to withstand the load acting upon it.

Hing And Its Reinforcement :