Design of backdoor

AIM:

Use the provided styling surface to come up with a back door design, use appropriate design methodologies, and provide the necessary reinforcements and embosses

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 of the luxury car door is electrically operated. I involve a very major role during rear crash cases. so, our design must be obeying crash requirements. the institute of highway safety analyse the different accidents and they set a test to rate our car. so these rating depends upon the design of the trunk and material used, flanges, embosses, type of joining of inner panel and outer panel etc.

Types of doors based on working position,

1. Top Mounted Door

2. Side mounted Door

3. Bottom Door

the back door is operated by two types of commodities.

1. Electrically operated

2. Gas stay powered.

the main purpose of these mechanisms is to open the back door without heavy efforts because the backdoor has 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 of commodities. and these also decides the premium of the car, mostly the electrically operated used in premium cars.

1.Gas stay powered.

2.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 in back door is material selection. mostly in past days steel is used, but it makes a very problems the steel parts have heavy weight, so it reduces the fuel economy, instead of steel presently in high end cars aluminium is used, the main objective of aluminium it have less denser material and its suitable for complex shapes, and it also gives the thickness locally because it done acting, in case of steel we used deep drawing operation. there are some of the advantages and disadvantages are there

.

so by using of aluminium we can reduce the number of parts and assembly involvement. and it is castly material.

these are the certain tests are done in back door, not only back door all components must pass these tests, but different components have different test because of the functional.

Different types of Sheetmetal operations 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 drawings having two main categories.

First- stage drawing: The blank shape of metal is placed on the die and contact with the punch. When the metal specimen is flat piece of sheet metal used in forming and finish the product. Initially the punch moves in downward direction. The outer rim of blank is subjected to pure radial drawing (drawing toward in vertical axes) 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 radii and stretch over punch head.

Redrawing: The components drawn from 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 as 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. 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:

Aluminium 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 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 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 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 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 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 considered as a waste.

BACK DOOR DESIGN

The design consideration of back door is,

· Visibility Criteria

· Force Dissipation

· Latch and Stricker Positions

· Hinge Position

· Gas Stay Position

· Hemming and Relief Areas

PARTS OF BACKDOOR

· Back door outer panel (upper and lower)

· Back door inner panel

· Hinge reinforcements

· Gas stays reinforcements

· Latch and striker reinforcements

· Wiper motor reinforcements

Inputs for designing of backdoor:

BACK DOOR OUTER PANEL

In this design back door is created as two different parts back door outer panel upper and lower. This outer panel designed based on visibility criteria and proper reliefs provided at the corner for hemming operation.

Back door outer lower: -

BACK DOOR INNER PANEL

Back door outer panel designed based on hinge, gas stay, wiper motor position and reinforcement as well as visibility criteria. Suitable tooling direction is created for trouble free manufacturing process. In this design stamping operations created based on this tooling direction. Embosses are provided in this design for force dissipation. In this design appropriate clearance given in mastic areas. The inner panel thickness is 0.75 mm.

Force dissipation

This inner panel design created by considering the force dissipation criteria. The embosses are created in such a manner that force will dissipate in to sides of the back door during a collision and prevent reaching inside the passenger cabin. Y and V embosses provided in the back door for force dissipation and improve the strength of the metal.

Mastic Area

Mastics sealants used for joining of outer panel and inner panel. It increases the strength of back door and good NVH. So accurate clearance given for mastic sealant.

Hemming

Hemming is a technology used by the automotive industry to join inner and outer closure panels together (hoods, doors, tailgates, etc.). In addition, adhesive bond provides for excellent joining of panels it also reduces vibration. here this design 0.2mm clearance provided for hem glue.

FINAL OUTPUT

Draft Analysis

Draft analysis performed to check the designed part is suitable for stamping operation with respect to the tooling direction. We can find out the errors by using this feature. The minimum draft angle is 7. The negative draft is denoted by different colour so we can easily find out the unsuitable areas.

CONCLUSION:

Above the Given Roof styling, create an ASSEMBLY by developing the essential flanges for the outer roof and creating the reinforcements.

Provide appropriate dimensions and check for Draft analysis.

Do a curvature study on the roof and perform calculations to determine the position of the Bow-roofs.

NOTES: - I unable to paste the images on the report so that i have attached a word file as the report. I unable to upload the ZIP file, So I attached a google drive link

https://1drv.ms/f/s!ApYgFZL7JKHwwyXui-sCT6RD6GZj?e=KQw9iz