Design of backdoor
Aim :
To develop the car Backdoor(Tail gate) with the reference of given skin data as per engineering standared by using NX12
Back Door :
The Back door is typically hinged, but sometimes attached by other mechanisms such as tracks, in front of an opening which is used for entering and exiting a vehicle.
A vehicle door can be opened to provide access to the opening, or closed to secure it. These doors can be opened manually, or powered electronically. Powered doors are usually found on minivans, high end cars, or modified cars.
Types of Back Door :
- Top Mounted
- Side Mounted
- Bootom Mounted
Top Mounted Back Doors :
Side Mounted Back Door :
Bottom Mounted Back Door :
Back Door Assembly:
- Inner panel
- outer panel
- hinge and its reinforcement
- wiper motor reinforcement
- latch & stricker and its reinforcement
Design Considerations In Back Door Design:
The following are the Design considerations taken while designing the Back Door. They are,
- Visibility Criteria
- Force Dissipation
- Latch and Stricker Positions
- Hinge Position
- Gas Stay Position
- Material Selection
- Space Availability
- Hemming and Relief Areas
All these design considerations go hand in hand with eachother because these positions are dependant on each other and if position gets altered all the positions has to be altered for effective opening and closing of the back door. The Latch and Stricker, Hinge Position and the Gas stay Positions has to be maintained in a proper way so that they play a major role in the opening and closing as well as the rear Visibility criteria of the car.
Different Sheetmetal processes used for manufacturing 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:
- 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, 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.
Design of Back Door Using Nx-CAD.
Given Class-A Surface.
Given Surface need to repair as their are some surfaces overlapping each other, which may create problem while working on it. After repairing surfaces the given suface is divided into two parts upper panel and lower panel.
Upper Panel.
Lower Panel.
Tooling Direction Creation for deep drawing operation.
Inner Panel.
Thickness provided - 0.75mm.
Once the tooling direction is created we need creatrethe 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, windshield panel is created and joined with sealing flange.
Embosses are created for Gas_Stay Mounting, Hinge Mounting, Striker Mouting and for wiper motor Mouting.
To create striker emboss the circle was drawn and line perpandicular to tangent of that circle was drawn. As sown in below image.
Hinge Reinforcement Creation.
Gas_Stay Reinforcement Craetion.
Wiper Motor Reinforcement creation.
Striker Reinforcement Creation.
Complete Assembly After thicknening all the components.
Draft Analysis.
Conclusion:
Thus the designing of the Back Door or Tail Gate is done as per Industrial standards and Manufacturing Techniques.