Design of backdoor

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

Introduction:

Rear door: rear door to tail gate simply refers to the back of the car that can open and close.it covering the rear of the vehicle,it provide access to a cargo area,A tailgate hinged at the roof is a predominant charactertic of hatchbacks,estates/station wagons and liftbacks,The door or opening of a cargo area may be hinged at the top,side or bottom.

In most cars,usually this process will be done manually,One has to get down the car to open and close the tail gate with the car key,Nowadays,automatic tail gate in the car will do the process of shutting and openging the tail gate electronically.

Manufacturing process:

Conventional tailgate assemblies are made from stamped metal panels welded together to form a tailgate,Latches are added on either side of the tailgate to engage a striker on the pickup sides,A handle operates the latches to open and close the tailgate assembly steel tailgate assemblies provide a durable and secure closure for the pickup bed.

Material for body panels:

Materials for car body panels require certain specific characteristics to meet the industery's challenges,rationalisation of specifications for leaner inventory,improved formabillity for reduced rejection rate and better quality.Higher strength low alloy steels of thinner 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 durabilitty and reliability.

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,etc,Blanking prepares the initial approximate form of the part in flat sheet.Drawing is generally the first operation to attain depth 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.

Process

• Blanking-When required blaning is the first step of the stamping process,blanking is the process of cutting large sheet or coil of metal into smaller,more manageable pieces,Blanking is usually performed when a stamped metal piece will be drawn or formed.
• Piercing-If a part requires slots,holes,or other cutouts,piercing can be employed,piercing,which can be performed simultaneously with blanking,punches the require shapes out of the metal sheet.
• 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 opening are deep drawn.
• Bending-bending is a fairly self explantory 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 bend piece of metal causes the entire part to deform.
• Hemming-Hemming is a technology used by the automotive industery to joint inner and outer closure panels together(hoods,doors,tailgates..etc)it is the process of bending/folding the flanges of the outer panel over the inner one.The accuarcy of the operation affects significantly the appearance of the car's outer surface and is therefore a critical factor in the final quality of a finishes cehicle.
• Roller hemming-The robotized hemming systems use a standard industrial robot intergrated with a roller hemming head,ofering a very flexible solution,This roller hemming head consists of a body some guides and a number of rolls that are designed according to the geometery of the part in each case.

Rear door design:

The design consideration of rear door are,

1.Visibility criteria

2.Force dissipation

3.Latch and stricker positions

4.Hinge position

5.Gas stay position

6.Hemming and relief areas.

Part of rear door.

1.Rear door outer panel(upper and lower)

2.Rear door inner panel

3.Hinge reinforcements

4.Gas stay reinforcements

5.Latch and stricker reinforcements

6.Wiper motor reinforcements

Rear door outer panel:

In the design rear door is created as two different parts rear door outer panel upper and lower,This outer panel designed based on visibility criteria and proper reliefs provided at the corner for hemming operation,The thickness of outer panel is 0.75mm.

Rear door inner panel:

Rear door inner panel designed based on hinges ,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.Embossess are provided in this design for force dissipation in this design for force dissipation,in this design appropriate clearance given in mastic area.the inner panel tickness is 0.75mm.

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 side of the back door during a collision and prevent reaching inside the passenger cabin,Y and V embosses provided in the rear 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 Increase the strength of back door and good NVH,so accurate clearance given for mastic sealant.

Reinforcements in inner panel

Hinge reinforcement:

In this design hinges provided on the top side of the door,approprite reinforcement given for hinge mounting areas to improve the strength.

Gas stay reinforcement:

Gas stays support the weight of the back door while they are open,more load act on this region ,so suitable reinforcement provided for better strength.

it is spot welded on the inner panel.

Wiper motor reinforcement:

Reinforcement provided in this region for fixing the wiper motor.

Latch and stricker reinforcement:

The stricker is designed to create a tight fit between the door and the seal on the cab,the door open and shut serveral times in a day,so more force acting on this area,the reinforcement given in the latch and stricker mounting area to increase the strength it is spot welding on the inner panel.

All reinforcement parts spot welded on the inner panel for better strength on that area

Trajectory:

The tractory is created to position the latch and stricker latch system must be able to catch the stricker of the door the while closing,circle is drawn from the hinge axis,the strickker follow this path.

Hemming:

Hemming is a technology used by the automotive industry to join inner and outer closure panels together(Hood,door,tailgate,etc)In addition adhesive bond provide for excellent joining of panels it also reduce vibration here this design 0.2 clearance provided for hem glue.

Proper corner relief provided for trouble free hemming operation.

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 error 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:

The reardoor is designed based on design considerations required reinforcement provided on inner panel,The design is checked by using draft analysis feature.

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