Hood design Using catia

Aim:

• To design a hood inner panel.
• To design hood outer panel with hem.
• Today develop necessary reinforcement.
• To provide necessary mastic data.

Tool used:

CATIA

Design Requirements:

• Skin data.
• Master sketch.
• Hemming data.
• Hood thickness information.
• Hinge And Latches.

Master section:

This is the master section I have used in this project.

HOOD:

• Hood is the hinged cover over the engine of the motor vehicles allows access to engine compartment.
• Inner panel provides strength while the outer panel functions as the metal cover.
• Inner panel will have all the embosses and cuts for mastics.
• Embosses are made in such a way that when a vehicle hits the force should directed towards the hinges.
• There are two types of embosses V-Type and Y-Type.

Hood Stay:

• Its a device for supporting the engine hood of a motor vehicle in its open position.
• There are two types of hood stay\'s

1. Support rod:

A device for supporting the engine hood of a motor vehicle in its open position by means of a rod.

2. Gas stay:

A device for supporting the engine hood of a motor vehicle in its open position by means of an actuator which is activated by gas.

• Hood inner panel will have reinforcements for Hinges and Latch&Striker.
• Latch&Striker are used for locking mechanism.

Hinge:

Hinges are used for opening and closing, they are attached to the car body and the hood inner panel.

Reinforcement:

Reinforcement is the additional strength for the cutouts made for hinge and latch.

• We also use stiffener pads to reduce the vibrations while the vehicle is in motion.

Mastic Seal:

• Mastic is a hard rubber which increases the strength of the hood.
• Every mastic seal have a tendency to increase strength local around 80mm.
• Mastics are placed in such a way that it covers strength all over the hood.

Emboss:

Embossing and debossing are the processes of creating either raised or recessed relief images and designs in paper and other materials. An embossed pattern is raised against the background, while a debossed pattern is sunken into the surface of the material.

(or)

Embossing is a metal forming process for producing the raised or sunken designs or relief in the sheet material by means of matched male and female roller dies.

Process:

The metal sheet embossing operation is commonly accomplished with a combination of heat and pressure on the sheet metal, depending on what type of embossing is required. Theoretically, with any of these procedures, the metal thickness is changed in its composition.

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.

Depending on the roller dies used, different patterns can be produced on the metal sheet. The pressure and a combination of heat actually \"irons\" while raising the level of the image higher than the substrate to make it smooth. The term \"impressing\" refers to an image lowered into the surface of a material, in distinction to an image raised out of the surface of a material.

In most of the pressure embossing operation machines, the upper roll blocks are stationary, while the bottom roll blocks are movable. The pressure with which the bottom roll is raised is referred to as the tonnage capacity.

Characteristics:

The metal embossing manufacturing process has these characteristics:

• The ability to form ductile metals.
• Use in medium to high production runs.
• The ability to maintain the same metal thickness before and after embossing.
• The ability to produce unlimited patterns, depending on the roll dies.
• The ability to reproduce the product with no variation.

Commonly used materials:

The following materials are suitable for embossing:

• Aluminium
• Brass
• Cold-rolled steel
• Copper
• Galvanized steel
• Hot rolled steel etc....

Embossing which I have used in this project is of v-type.

When the vehicle crashes the forces travells in the direction of the arrows such that entire force goes toward hinges and decreasing the force on the driver.

Mastic Data:

This is the mastic places I have used which covers entire hood, at the places of hinge and latch, their reinforcements strengthen them because we use hinge reinforcement and latch reinforcement.

We use cuts in the inner panel to decrease the weight of the hood.

Hemming:

• Hemming is the process in which the edge is rolled flush to itself.
• Hems are commonly used to reinforce an edge, hide burrs and rough edges, and improve appearance.
• The process starts by bending the edge to an acute angle. A flattening die is then used to flatten the hem.
• There are two types of hemmed edges: closed hems and open hems. Closed hems are completely flush while open hems have an air pocket in the bend. The major difference is that the tonnage required for a closed hem is much greater than that for an open hem.
• We should provide some relief in hemming around the round edges which gives better strength.

Relief:

This is the cad model: