Hood design-Week 2
Hood Design :-
The important criteria for the car sheet metal design is hood design. It is the protection of the engine components and for front collision. The design of hood should such that when front collision is occurs then force act on it should be go upward direction through the by embosses it not go from the centre.
Master sketch:
We have to used the given information about the part as :-
Hood Thickness Information
- Outer Panel Thickness = 0.75mm
- Inner Panel Thickness = 0.75mm
- Reinforcement Thickness = 1.5mm
The hood consists of the follwing parts :-
1. The Outer Panel
2. The Inner Panel
3. The Latch / Striker &
4. The Hinge
When we design the hood we have to consider the some parameters such as follow :-
1. The Latch is placed at the centre of the hood.
2. Hinges axis should be match each other.
3. Most important while hemming the outer and inner panel should not be intersect with each other.
4. Corner reliefs should be given for the hemming process.
Features created in the designing the inner panel :-
Emboss:-
It is the stamping process for producing raised or relief in the sheet metal. Embossing is a forming process in which a high pressure is applied to a workpiece to change its surface. Depending on the shape, a distinction is made between hollow embossing and solid embossing.
It help reduce friction and static, bolster metal panel stiffness and rigidity, increase metal surface area for acoustic or heat transfer and improve traction.
Mastic Region :-
This region is provided on the inner panel. On this area mastic sealant is applied to jion the inner panel with the outer region. Mastic sealant is used to reduce the noise and vibrations.
Hinges :-
It is jointed or flexible device on which a door, lid, or other swinging part turns. After this we have to placed the hinges on the inner panel with the proper so both the hinges are have same axis.
It is advantages including the ability to maintain the frame of the door in an exact position to minimize wear and tear.
Latch :-
This is the part which helps in closing the hood of car. A vehicle hood latch and release mechanism is latched when the hood striker engages the latch portion of the mechanism as the hood is moved to its closed position.
In the mid plane of the assembly draw a circle from the hinge centre point. draw a line tangent to the circle and from the centre of the circle draw a line perpendicular to the tangent line.
In the same way draw the line at centre of the latch and change referance set to entire point so that the sketch is visible in the assembly.
Then use the assembly constraints on it and then placed the latch.
Features created in the designing the outer panel :-
Hemming :-
At the corners the outer panel and inner panel are joined together by hemming. Here welding is not done due to less size of sheet and it leaves the sign so only hemming is done.
In car part production, hemming is used in assembly as a secondary operation after deep drawing, trimming and flanging operations to join two sheet metal parts (outer and inner) together. Typical parts for this type of assembly are hoods, doors, trunk lids and fenders.
There are various types of hemming operations:
- Conventional die hemming
- Roll hemming
Deep drawing :-
The deep drawing process is a forming process which occurs under a combination of tensile and compressive conditions. A flat sheet metal blank is formed into a hollow body open on one side or a hollow body is formed into a hollow body with a smaller cross-section.
Deep drawing processes are divided into three types:
- Deep drawing with tools
- Deep drawing with active means
- Deep drawing with active energy
Corner relief :-
After hemming we have to give the corner relief on the outer panel.
Corner Relief tool to add relief to one or more corners of a sheet metal part. When you add relief, sheet metal sections are removed from the model.
Relief helps to control sheet metal material behavior and to prevent unwanted deformation during unbend operations.
In this way our hood design is done.
