Design of backdoor
Design of back door
AIM:- To design the back door using the provided styling surface and by using appropriate design methodologies and by providing the necessary reinforcements and embosses.
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 the back door:-
Top-Mounted:- This type of back doors is used in a station wagon, pickup truck and some of the sport utility vehicles. Today’s modern cars use top-mounted tailgating systems which are both powered and also gas stay supported. These top mounted tailgates provide greater rear visibility compared to side-mounted or bar doors which have canter pillars in it.
Side Mounted Doors:- As the name signifies side-mounted doors are the one which is used in the van type MPVs, SUVs, pickup truck vehicles. These side-mounted doors or barn doors are a lot easier compared to top-mounted doors. These doors are generally smaller in size and can be easily accessed. These doors are more convenient for the goods handlers for long pipe and lengthy components where one door is kept open. These doors also save accidental head impacts. It is a lot easier to load and unload items in the side-mounted doors.
Bottom / split type:- This bottom type or split type backdoor system are used in the car type such as estate type car, pickup trucks and some luxury SUVs.These are the most convenient type of back door in which the bottom split is used as a support or even as a table for the tour going people.
Types of mechanisms for Rear Door
Gas stays type:-Gas stay types backdoor/liftgate/tailgate is an ideal and most commonly used tailgate mechanism from lower segment car to luxury car segment. The ideal components of tailgate consist of a hinge, door, gas stay and some rubber beadings for sealing of door.
Powered lift system:- Power trunk lid system is another sophisticated way of trunk/liftgate opening mechanism which is to automatically open and close of the trunk/liftgate and release of the latch by the touch of a button. The following image shows the component as used in the powered trunk/back door lift system. Powered trunk lift system consists of a power latch, anti-pinch switch, PTG ass’y, PTG main switch. When the switch is pressed in the compartment or outside the power latch releases the latch and the entire backdoor is opened. The anti-pinch switch is located in order to avoid accidental hand insertion during the operation of the door.
DIFFERENT METHODS OF MANUFACTURING FOR BACK CAR DOOR
Blanking:-Blanking is a metal fabricating process, during which a metal workpiece is removed from the primary metal strip or sheet when it is punched. The control of the quality by the punch and die clearance. The ability to produce holes of varying shapes – quickly.
Deep drawing:-Deep drawing is a sheet metal forming process in which a sheet metal blank is radially drawn into a forming die by the mechanical action of a punch. It is thus a shape transformation process with material retention. The process is considered "deep" drawing when the depth of the drawn part exceeds its diameter.
Trimming:-Trimming is a manufacturing process that is used as a finishing operation for forged parts, in order to remove flash. Most often it is desirable to perform this operation while the work is still hot for maximum efficiency, therefore it is usually incorporated into the larger production process.
Hemming:-Hemming is a sheet metal forming process in which sheets are joined by bending it usually to 180°. Automotive body panels and automotive parts such as deck-lids, trunk-lids, doors, hoods and tailgates are formed by hemming process.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.
- The outer panel was designed as two different parts named as outer upper panel and outer lower panel.
- After designing the outer panel the Hemming was created by offsetting the surface with the help of face blend & swept surface.
- The two different outer panels will be joined using Blanking
CORNER RELIEF:-During the hemming process, when giving the Corner Relief helps to control sheet metal material behavior & to prevent unwanted deformation during unbend operations & also helps to minimize the number of passes in hemming.
BACK DOOR ASSEMBLY:- The back door assembly of a car has the following components.
- Inner panel
- Outer panel
- Hinge reinforcement
- Gas stay reinforcement
- Wiper motor reinforcement
- Latch/striker reinforcement
In this design outer panel is divided into two-part.
- Outer Upper Panel
- Outer Lower Panel
Outer Upper Panel:-
The Outer Upper Panel Extracted from a provided styling surface.
The panel is modified for the required design with the surface tools of NX CAD.
The thickness provided to the outer panel is 0.75 mm.
Hemming is provided with corner reliefs.
Outer Lower Panel:-
The Outer Upper Panel Extracted from the given styling surface.
The panel is modified for the required design with the surface tools of NX CAD.
The thickness provided to the outer panel is 0.75 mm.
Hemming is provided with corner reliefs.
Outer Upper & Lower Panel
Tooling Direction:
- Before starting to design the inner panel of the back door the tooling direction for Deep Drawing purposes should be created.
- Then the styling surface needs to be checked properly and analyzed since it might have irregularities, hence it must be fixed first.
- The back door was designed using a top-down approach.
DESIGN OF BACKDOOR INNER PANEL
The inner door panel is a component which is used for strengthening the door assembly and it is one of the most important components on which all accessories are mounted like hinges, glass guide channel, moulded trim, latch etc. The possible method is the integration method. In the integration method, the part is stamped out of a single blank. This reduces the number of tools needed; the assembly cost and eliminates any fit ability problem.
The Inner Panel Extracted from a given styling surface.
The panel is modified for the required design with the surface tools of NX CAD.
The thickness provided to the outer panel is 0.75 mm.
DESIGN OF OUTER PANEL:-
The outer panel of the back door is similar to other BIW components where it is the aesthetic part of a vehicle. The coating provided is of multi-stage which has the property of scratch resistance, rust prevention and smooth and attractive finishes. The outer panel also has the provisions for the tail lamp, rear fog lamp and also has the provision for licence plate mountings. Most of the hatchback cars have the provision for wiper motor.
DESIGN OF REINFORCEMENTS:-
Reinforcements basically strenghts or increases the mechanical properties of the material. The hinge reinforcements are provided so as to increases the strength during bolting.
The thickness provided for all reinforcements is 0.75 mm.
The different types of reinforcements used here are.
- Hinge reinforcement
- Gas stay reinforcement
- Wiper motor reinforcement
- Latch/striker reinforcement
Hinge reinforcement:-
Hinges allow the opening and closing of the back door. One end of the hinge is fixed on the backdoor and the other end on the Roof. Hinges can be placed outside or inside the backdoor.
The hinge reinforcements are added to compensate for the weak region due to the acting load over it.
Gas Stay Reinforcement:-
Gas Stay is a device used to support the back door in its open position. Gas stay requires no manpower & it is engaged into support position automatically as the back door opens. One end of the Gas Stay is fixed on the backdoor & another end is on the Body Side or on the Back door stationary area.
Embossing is provided at the Gas Stay mounting area to compensate for weakness & improve strength.
Wiper Motor Reinforcement:-
As the name suggests, wiper is used to wipe off the dust and water from the rear windscreen of the vehicle.
Wiper motor reinforcement is made to mount the wiper motor assembly.
Latch and Striker Reinforcement:-
The Latch & Striker together form the locking mechanism of the backdoor with the car. Due to regular opening, closing, and over slamming of the backdoor, there is stress developed in the Latch & Striker area. To recoup for the same, reinforcements are added in this area.
DRAFT ANALYSIS:-
- The draft analysis was performed for the tooling direction created at first and checked that the model is suitable for manufacturing.
- Then to get a complete green portion the required changes to the draft angle of the embosses were carried out by optimizing the model.
- The Draft Analysis command is used to detect that the part drafted will be easily removed or not.
- This type of draft analysis is performed based on color ranges.
- The identifying zones on the analyzed element where the deviation from the draft direction at any point, corresponds to specified values.
Inner Panel draft analysis
Outer Panel Upper Draft analysis
Outer Lower Panel draft analysis
Hing Reinforcement RH and LH Draft analysis
Gas stay reinforcement RH and LH Draft analysis
Wiper motor and Latch Mount Draft analysis
Conclusion:-
Thus the back door was designed from the given styling surface and Draft analysis is also done on the inner panel to check the manufacturing conditions. In this challenge i learned to design the Inner panel, the Outer panel, Wiper Motor reinforcement, Hinge reinforcement, Gas Gtay reinforcements, Latch and Striker reinforcement and its position.