Hood design-Week 2

Hood latches are simple by design but can certainly be tricky at times, especially because every make and model is slightly different.

In general, the hood latch system starts with a release handle located on the left side of the driver’s area.

This handle is connected to an insulated cable that runs towards the front of the vehicle. The other side of the cable is connected to a latch under the hood that keeps the hood flush against the car’s body.

Pulling the interior release handle will disengage the latch and open the hood a few inches. Once the latch has been disengaged, and the hood lifts a few inches, a safety latch will stop the hood from being fully raised.

You’ll need to reach under the hood and feel around for a manual release lever to release the safety latch. The placement of the release lever varies by make and model but tends to be towards the center of the vehicle. Pull the safety latch’s manual release to lift the hood up all the way.

The hood inner panel and outer panel are joined together after the joining there will be a gap which leads to noise due to vibration. In order to reduce the noise produces by the vibration mastic seals are provided in between them which improves NVH(Noise Vibration Hardness).Each mastic points has influences of 80mm. It is a paste like substance which gets hardened by application of heat.

The deep drawing of sheet metal is performed with a punch and die. The punch is used to achieve the desired shape. The die cavity matches the punch; however, it is slightly wider, allowing for passage and clearance. Similar to sheet metal cutting, the clearance is the lateral distance between the die edge and punch edge.

The sheet metal, called a blank, is placed over the opening of the die, where a blank holder surrounding the punch applies pressure to the entire surface of the metal, except the area under the punch. With the blank flat against the die, the punch then moves towards it and makes contact. The punch forces the sheet metal into the die, forming its shape.

Each draw operation is a separate step, and with each step there is a reduction in diameter, increasing the height of the part. To complete the part, there may be several draws, or reductions, made to achieve the desired parameters.

In this process, there are several circumstances to consider when manufacturing an enclosure:

• Material type
• Thickness
• Corner radius
• Bottom radius
• Shape

Both mechanical and hydraulic presses are used in the deep draw manufacturing process. Precision punches and dies are tools usually made of steel and iron. However, materials for punches and dies can span from plastics to carbides. Deep drawn parts are usually created at speeds of 4″-12″ per second.

Hemming Process

A hem bend is an edge of sheet metal that is bent 180 degrees and flattened on top of itself.Hemming is the process in which the edge is rolled flush to itself, while a seam joins the edges of two materials.