Design of backdoor

AIM:

INTRODUCTION:

BACK DOOR:

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 provide access to a cargo area (trunk/boot ).A tailgate hinged at the roof is a predominant characteristic 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, automobile manufacturers providing Advanced features like the automated tail-gate. An automatic tail-gate in the car will do the process of shutting and opening the tail-gate electronically.

BACK DOOR DESIGN:

The design consideration of back 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.
• PARTS OF BACKDOOR:
• Back door outer panel (upper and lower),Back door inner panel,Hinge reinforcements,Gas stay reinforcements,Latch and striker reinforcements,Wiper motor reinforcements.
• 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 .The thickness of outer panel is 0.75 mm.

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..

• Hinge reinforcement:

In this design hinges provided on the top side of the door. Appropriate 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 striker reinforcement:

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 reinforcement given in the latch and striker mounting area to increase the strength.it is spot welded on the inner panel.

trajectory line:

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 and Relief Areas:

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 provide for excellent joining of panels it also reduce vibration .here this design 0.2mm 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 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.

design methodology:

Important features used while designing:

• Wave Geometry Linker –- With this you can create, associative or linked copies of any entity of a part into other parts. It may be a surface, edge, curve, body, sketch etc. The changes made to the original entity will be reflected in the copy of that entity.
• Extract Body – It is used to create an associative body by extracting faces, entire body or region of faces.
• Bridge Curve – It helps to create a tangent blend curve between two objects. The objects may be edges or sketch curves.
• Sew – It combines sheet bodies together by sewing their common edges. There shouldn’t be any gaps larger than specified tolerance.
• Unsew – This command is used to separate the existing sheet body or solid body into multiple bodies.
• Projected Curve – It is used to project an existing curve/curves on a selected plane or surface by selecting a direction for projection.
• Trim Body – It is used to trim one or more bodies using a face or plane. You can also specify the bodies to retain and the bodies to discard.
• Offset Surface – It allows you to offset one or more existing surfaces.
• Offset Curve in Face – This command will allow you to offset particular edges or curves on selected faces.
• Trim Sheet – It is used to trim off a portion of a sheet body using curves, faces, edges or planes..
• Through Curves – It will allow you to create a body Through multiple sections, where it’s shape changes to pass through each section.
• Law Extension – This command extends a curve or edge to create a sheet body at desired angle length by changing the rules under angle law and length law.
• Trim and Extend – It helps you to trim and extend intersecting surfaces and make corner at their intersection.
• Face Blend – It creates fillets between faces.
• Edge Blend – It creates fillets on edges.
• Extend Sheet – It will allow you to extend an existing surface to required distance.
• Emboss – Emboss command creates an embossing by modifying a body with faces created by projecting a curve/section along a direction. You can modify the emboss using options like endcap location and draft angle.
• Mirror Geometry – As name suggests, it allows you to mirror geometries about selected plane or surface.
• Thicken – It is used to convert a surface to solid body by providing thickness.
• Extrude – It helps you to create a feature from a sketch. You are also able to create thin feature using a sketch or curve under this command.

full assembly of tail gate:

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.

Another disadvantage of steel tailgate assemblies is the cost of the tooling required and equipment required to stamp metal tailgate components. Metal tailgate components are generally produced in a large stamping press. The stamping presses generally require finely machined tools made from hardened steel. The cost of tooling a metal tailgate is much more expensive.

STAMPING PROCESS :

Stamping processes 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 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 required, blanking is the first step of the stamping process. Blanking is the process of cutting larger sheet 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 opening are 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 (hoods, doors, tailgates, etc.). It is the process of bending/folding the flange of the outer panel 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.

6 roller hemming

The robotized hemming systems use a standard industrial robot integrated with a roller hemming head, offering 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 geometry of the part in each case.

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.

To development team:

the unproper hemming as present in this process so increase the special feateure in class a surface and provide proper hemming blend on this tail gate model.

(negative draft present on the joining hemming side so improve the angele value on lawextension process and get proper draft value model.

CONCLUSION :

The backdoor is designed based on design considerations .Required reinforcement provided on inner panel. The design is checked by using draft analysis feature .

(note : the model 1 -inner pannel only send zip file other as same as prt file cause itz above 20 mb)