Challenge

Design of backdoor

RRajesha Dn6 Nov 2022

Design of backdoor

Aim: To design the back door of the car and make inner panel for the back door and also design the necessary re-enforcements.

Software: NX 10

INTRODUCTION:

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

Types of Door based on working position:

1. Top Mounted Door

2 Side Mounted Door

3. Bottom mounted Door

The back Door is operated by Two types of Comidities:

The main purpose of tghese mechanisum is toopen the back door without heavy efforts, becouse 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 introdused these two types comodities. and these also decides the premium of the car, mostly the electrically operated used in premim cars.

1. Electrically Operated

2. Gas Stay powered

Back Door Assembly:

Inner Panel
Outer Panel
Hinge and its reinfforcement
Wiper Motor reinforcement
Latch and Striker reinfocement
Gas stay reinforcement

The major problem in back is material selection. Mostly in past days steel is used, but it makes avery problems the steel parts have heavy weight, so it reduces the fuel economy, insted of steel presently in high end cars aluminium is used, The main objective of alluminium it have less denser material and its suitable for complex shapes, and it also gives the thickness locally becouse it is done coating, in case of steel we used deep drawing operation. there are some of the advantages and disadvantages are there.

So by using of alluminium we can reduce the number of parts and assembly involvement. and kits costly material

Difference between Aluminum and Steel parts:

Aluminum	Steel
1] Parts are casted	1] Parts are stamped
2] Reinforcements can be neglected	2] Reinforcement are necessary
3] Local Thickness can be varried	3] Has only uniform Thickness
4]Lighter in weight	4] Heavier in weight
5] Less number of components	5] More nomber of components

Different types of Sheetmetal Process are done in the Back Door

Deep Drawing:

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

1. First-stage Drawing: The blank shapes of metal is placed on tghe die and contact with the punch. When the metal specimen is flat piece of sheet metal used in forming and finish the product. Intially the punch moves in downword direction. The outer rim of blank is subjected to pure radial drawing (drawing toword in vertical axis)between die and blank metal. The metal become a bend and sliding over die and also stretched between die and punch. The metal in vicinity of punch head and contact with it bend and slide over radial and stretch over punch head.

2. Redrawing: The components drawn from first stage again it is redrawn convert intmore depth toform a cup shape in the die and punch . The Secand stage of drawing is called as redrawing.

3. Embossing: Embossing is a metal forming process for produsing raised or sunken designs or reliefe in sheet materials by means of matched male and female roller dies, theoritically with no change i metal thickness or by passing sheet or strip of metal between rolls of the desired pattern. Metal sheet sheet is drawn through the male and female roller dies produsing a pattern or design on the metal sheet. dipending on the roller dies used, different pattern or can be produced on the metal sheet.

Materials commonly used in the metal embossing process include:

Aluminium alloys
Steel alloys
Zink
Copper
Galvanized steel
Brass
Cold rolled Steel

Hemming: Hemming is a forming operation in which the edges ofthe sheet are folded or folded over another part in order to achieve a tight fit. Normally 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 secandary operations after deep drawing, trimming and flanging operations to join two sheet metal parts (Outer and inner) together. Typical parts for this type assembly are hoods. doors trunk lids and fenders.

There are verious types of hemming operations.

1. Conventional Hemming: In conventional die hemming, the flange is folded over the entire length with a hemming tool.

2. 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 open hem bend angle is equal to 180 degrees.

Tear drop Hem: In tear drop hem the bend angle is greater than 180 degrees.

Closed Hem: Hems without any inside radius are called as closed hem closed hems are not recommended if the hem geometry is tobe painted or if the material used is SST or Aluminium.

Blanking:

Blanking is a cutting operation of a flat metal sheet and the artical punched out is known as blank, Blank is the required product of the operation and the metal left behind is considered as 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 cosidered as a waste.

Inputs for Designing of back Door:

1. Outer panel - 0.75 mm

2. Inner Panel- 0.75mm

3. Reinforcements- 1.5 mm

Class a surface:

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

First, we need to create the tooling direction for the deep drawing operations like embossing is done by considering this vector direction and it will help in manufacturing the part,

After that we have to create Sealing Flange by offseting the outer panel to the 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 thickning direction.

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

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

Trajectary path

Tooling Dirction

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.

Hinge Emboss and Reinforcement