Design of backdoor
Back Door Design
Aim:
To Design the Back Door of the car by the given Surface and also Design the outer panel and the inner panel by the given surface and design the reinforcements.
Objectives:
To Design the inner panel of the car with design parameters and also design the Mounting on the Inner panel like,
- Hinge Mounting
- Gas Stay Mounting
- Latch Mounting
- Wiper Mounting
To Design the Reinforcements for the mountings Designed.
To Design The Outer panel upper and lower by the given surface.
Done Draft Analysis on the Inner panel .
Introduction:
Back Door or Tail gate simply refers to the back of the car that can open and close,
it covering the rear of the vehicle.It provides access to cargo area.A tailgate hinged at the roof is a predominant characteristic of thehatchbacks,estates and liftbacks.The Door or opening of a cargo area may be Hinged at the top,side and bottom.
In most cars,usually this process will be done manually.One has to get down the car to open and close the Back Door with the car key.Nowdays,in automobile manufacturers providing Advanced Features like the automated Back Door.An automatic Back Door in the car will do the process of shutting and opening the Back Door automatically.
Manufacturing Process:
Conventional Back Door assemblies are made from the stamped metal panels welded together to form a back door.Latches are added on the either side of the back door to engage a striker on the pickup sides.A handle operates the latches to open and close the back door assembly.Steel back door assemblies provide a durable and secure closure for the pickup bed.
Another Disadvantage of steel back door assemblies is the cost of the tooling required and equipment required and the equipment required to stamp metal tailgate components.Metal tailgate components.Metal tailgate components are generally produced in a large stamping press.The stamping presses generally require finely machined tools made fron hardened steel.The cost of the tooling a metal tailgate is much more expensive.
Materials For Body Panels:
Materials for car body panels require certain specific characteristics to meet the industry's challenge,rationalisation of specifications for car leaner inventory,improved formability for reduced rejection rate and better quality.Higher Strength Low Alloy(HSLA) steels of thiner gauges,are getting preference for weight reduction and the resulting better fuel economy.Other quality characteristics under demand are higher yield stress,toughness,fatigue,strength,improved dent resistance as well as corrosion resistance in materials used for body panels for improved durability and reliability.
To obtain consistent quality of autobody skin panels without failures during stamping,the formability/ductility specifications of strips steels ae the basic requriements.Most of the steels used in automotive application are aluminium-Killed steels of about 0.7mm to 0.9mm thickness.
Stamping Process:
Stamping process to be used for a panel depend on its design.However,Normally the processes used extensively are Blanking,Drawing,Piercing,Forming,Notching,Trimming,Hemming and etc.Blanking prepares the initial approximate form of the part in flat sheet.Drawing is generally the first operation to obtain depth related form.Piercing,Notching,Hemming are product Design related operations.Trimming generally removes the extra material on the periphery of the panel provided for blankholding during draw operation.Decision on trim line is very important and becomes deciding factor to obtain good draw.
1.Blanking:
When requried,Blanking is the first step of the stamping process.Blanking is the process of cutting larger sheets or coils of metal into smaller,more manageable pieces.Blanking is usually performed when a stamped metal piece will be drawn or formed.
2.Piercing:
If a part requires slots,Holes or other cutouts,piercing can be employed.piercing,which can be performed simultaneously with blanking,punches the requisite shapes out of the metal sheet.
3.Drawing:
Drawing is the actual stamping in the metal stamping process.A punch forces a section of metal through a die,providing the primary shape of the part.when the depth of the part is less than the primary opening,it is considered shallow drawing,parts with a depth greater than the openingare deep drawn.
4.Bending:
Bending is a fairly self explanatory process.The part in progress is placed on a specially designed die and a ram pushes against the metal,providing the required bend.Bending is performed after Drawing,as attempting to punch an already bent piece of metal causes the entire part to deform.
5.Hemming:
Hemming is a technology used by the automotive industry to join inner and outer closure panels together.It is a process of bending/folding the flange of the outer panels over the inner one.The accuracy of the operation affects significantly the appearance of the car's outer surfaces and is therefore a critical factor in the final quality of a finished Vehicle.
Roller Hemming:
The robotized hemming systems use a standard industrial robot integrated with a roller hemming head,offering a very flexible solution.This rooler hemming head consists of a body some guides and a number of rolls that are designed according to the geometry of the part in each case.
Back Door Design:
The Design considerations of back door are,
- Visibility criteria
- Force Dissipitation
- Latch and striker positions
- Hinge Position
- Gas stay Position
- Hemmiing and Relief Areas
Parts of Back Door:
- Back Door outer panel Upper and Lower
- Back Door Inner panel
- Hinge Reinforcements
- Gas Stay Reinforcements
- Latch and striker reinforcements
- wiper motor reinforcements
1.Back Door Outer Panel:
In this design back door is created as two different parts back door outer upper and lower panel.This Outer panel designed based on the vivibility criteria and proper reliefs provided at the corner for hemming operations.The thickness of the outer panel is 0.75mm
2.Back Door Inner Panel:
Back Door inner panel is designed based on the hinge,gas stay,wiper motor positions 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 appropriate clearance given in mastic areas.the inner panel thickness is 0.75mm.
3.Force Dissipitation:
This inner panel design created by considering the force dissipitation critertia.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.The embosses is provided in the back Door for force dissipitation and improve the strength of the metal.
Mounting Locations:
Reinforcements in Inner Panel:
- Hinge Reinforcement:
In this design hinges provided on the top side of the door.Appropriate reinforcements given for the hinge mounting areas to improve the strength.
- Gas Stay Reinforcements:
Gas stay supports the weight of the back door while they are open.More load act on this region,so suitable reinforcements provided for better strength,it was done by th spot welded on the inner panel.
- Wiper Motor Reinforcement:
Reinforcement provided in this region for fixing the wiper motor.
- Latch and Striker Reinforcements:
The striker is designed to create a tight fit between the door and the seal on the cab.The door open and shut several times in a day.so more force acting on this area.The reinforcements given in the latch and striker mounting area to increase the strength.it is spot welded on the inner panel.
Trajectory Motion:
The trajectory is created to position the latch and striker.latch system must be able to catch the striker of the door the while closing.Circle is drawn from the hinge axis.The striker follow this path.
Hemming:
Hemming is a technology used by the automotive industry to join inner and outer closure panel together.In addition adhesive bond provide for excellent joining of panels it also reduce vibration.Here this design 0.2mm clearance provided for hem rule.
Proper corner relief provided for trouble free hemming operations.
Draft Analysis:
The Draft Analysis is performed to check the designed part is suitable for stamping operations 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 color so we can easily find out the unsuitable areas.
Conclusion:
The Back Door is designed based on the considerations.Required reinforcements provided on the inner panel.The Design is checked by using draft analysis feature.
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