Project 2

PROJECT 2

BACK - DOOR WIRING HARNESS

OBJECTIVE:

To route the wiring harness for the given car back door assembly part and prepare a flattened view by applying the packaging rules and also apply the protection coverings as needed.

ABSTRACT:

The wire harness assembly process is a complicated manufacturing activity, which is becoming more complex because of the evolving nature of mechatronic and electronic products that require more connectors, sensors, controllers, communication networking, etc. Furthermore, the demand for wire harnesses continues to grow in all industries worldwide as the majority of equipment, appliances, machinery, vehicles, etc., are becoming “smart” (i.e., more mechatronic or electronic). Moreover, most of the wire harness assembly process tasks are done manually, and most of these are considered non-ergonomic for human assembly workers. Hence, the wire harness manufacturing industry is faced with the challenge of increasing productivity while improving the occupational health of its human assembly workers.

INTRODUCTION:

Automobiles and other road vehicles such as trucks and buses are one of the most demanding applications for mechanical and electrical design. The electrical systems in these applications must operate properly over a wide range of environmental conditions, facing extreme temperature, humidity, sunlight, dirt, vibration, and more. The electrical system must also meet user expectations of reliability and mandatory safety-critical design practices. With the growing focus on Autonomous driving, Advanced Driving Assistance System (ADAS), and infotainment platforms, a sophisticated electrical system that underlies the vehicle must be handled efficiently and should not generate any electrical hazards for the safety of the passengers and vehicle as well.

LITERATURE REVIEW:

The trunk or boot of a car is the vehicle's main storage or cargo compartment it also have a hatch at the rear of the vehicle. It is also called a tailgate. These doors can be operated manually or electric powered. here we design the trunk or back door wire harness using the CATIA. The Backdoor is an assembly of many parts such as inner panel, outer panel upper, outer panel lower and Reinforcement. Inner panel is attached to the outer panel using mastic sealant.

WIRING HARNESS:

The wiring harness is the combination of electrical cables, or assembly of wires, that connects all electrical and electronic (E/E) components in the automotive vehicle, like sensors, electronic control units, batteries, and actuators. The wiring harness handles the energy and information flow within the E/E system to full-fill primary car functions, such as steering and braking as well as secondary car functions, such as ventilation and infotainment.

A wiring harness routing structure includes a wiring harness routing member configured to be attached to a vehicle body and a protector that accommodates and holds a wiring harness. The protector has a recess shape in which the protector is opened in one direction in a sectional view. At least one of the wiring harness routing members and the protector includes a fixing mechanism that fixes the protector to the wiring harness routing member. The protector and the wiring harness routing member are configured to be integrated via the fixing mechanism.

Electrical Harness Flattening operation is used for converting the 3D format of the wiring harness geometrical bundles into associated 2D drawings, which will be taken as a reference during the various stages of manufacturing, assembling, installation and servicing of wiring harness.

Once a product is ready to manufacture, its design must be precise or it risks costly errors and delays. Collaboration is the essential key to successful documentation and design between harness designers and manufacturing. CATIA – Electrical Wire Harness Flattening provides automatic and complete flattening of 3D Electrical Harnesses for manufacturing documentation in a concurrent engineering environment.

MATERIALS CHOOSE FOR WIRING HARNESS:

There are various components that are teamed up to make a wire harness; and you must be sure about the choice of each one of these. And, in order to make the right choice, you must first understand all the environmental conditions and other factors that your wire harness or application will be subject to. Will the environment be highly humid or extremely hot? Will the product have to bear excessive pressure or abrasion? After you understand the requirements completely, you will be in a better position to make the right choice. Here is a complete list of all the components that you need to consider while planning up a customized wire harness; and each one comes with a list of the various options available.

Conductor:

Conductor is the very important material in a wire harness that allows the flow of an electrical current in one or more directions within the wire. The most common material used is copper, but there are many other options like nickel, silver, tin, and aluminum too.

Insulation and Jacketing:

Insulation is a covering that protects the conductor against any kind of current leakage. Also, any incoming physical abuse can be prevented with the help of insulation. Over the insulation comes another protective layer of jacketing, which is designed to protect the wires against chemicals, moisture, and mechanical damage. The most popular insulating and jacketing materials used include –

· PVC – The material can perform effectively at temperatures between -20 to 105°C, and has good fire resistance, chemical resistance, UV resistance, durability, and flexibility.

· Polyethylene and polyurethane – Both these materials can perform effectively at temperatures between -60 and 80°C, and have good chemical resistance, UV resistance, durability, and flexibility; but are very poorly resistant to fire.

· Thermoplastic rubber or elastomer – The material can perform effectively at temperatures between -40 and 90 °C, and is surprisingly good in terms of fire resistance, chemical resistance, UV resistance, durability, and flexibility.

Fillers:

Fillers may be used to strengthen the cable by supporting the outer layers, and increasing the flexibility of the construction, while also offering a rounder and smoother construction. The most popularly used fillers include –

· Polyethylene, which is a lightweight material that can be easily moulded, making it ideal for longer wires.

· Cotton, which is a low-cost solution as the durability is comparatively lesser, but the flexibility offered is good.

· Steel, which is highly strong and durable, and can be tied off at either end of a harness, to transfer any force the wire encounters, away from the conductors, and onto a housing inside the harness.

· Foam, which can be made out of a variety of materials, effective for filling in small spaces between wires, and retaining the wire harness shape.

METHODOLOGY:

There are several factors to consider when designing a cable assembly or wire harness for the given application and the entire vehicle wiring harness is designed accordingly.

Harness passes through many areas where it requires protection against heat, dust, moisture etc. Wire harness protection prevents damage caused by wire vibration damage, abrasions and incidental contact with other pieces of heat producing equipment.

RULES FOR WIRING HARNESS:

· Wiring harness should be routed in such way that it is easy to assemble and access.

· Easy manufacturing, installation, removal and maintenance have to be considered while designing the wire harness.

· wiring Harness should be kept away from sharp environment like edges, corners etc.

· Avoid harness routing and clipping in the blind zones or hard to reach areas during harness assembly or service.

· Provide additional slack if needed according to the surrounding and harness bending requirement. If harness is passing through the closures/doors or tail gates then envelope dimensions during opening and closing of doors shall be considered to provide the slack. Check the harness slack requirements with open and close conditions to avoid excess slack.

· Routing through small structural holes and openings shall be avoided. To minimize chaffing and handling of the wiring harness during installation.

· It should be make sure that there is no case of fouling while designing the wiring harness in the CAD environment. Additional mounting equipment’s like clips/clamps may be used to avoid fouling.

· Use of rubber grommet is recommended if harness is passing through sheet metal panels. Example- firewall, passing to doors.

· The branch length should be minimum 50 mm.

· The minimum distance between the clip and branch point should be at least 25 mm.

· The minimum distance between the two branch points should be at least 50mm

· Clips/clamps used for the wiring harness should be easily available in the market to avoid extra cost for custom mounting solutions.

Step 1:

Download the given back door assembly CAT part file and also download all the required connectors. In this project I use dummy connectors not exact one.

Step 2:

Create a context assembly file, paste the back door file here and create Geometrical bundle file within this context assembly.

Step 3:

Define the connectors electrically and arrange it in the geometrical bundle segment. By using the manipulation or smart move arrange all the connectors at the perspective places.

One is Inter connection connector and other one is for danger light connection connector.

Step 4:

Define the geometrical bundle file as geometrical bundle segment and start the routing by using multibranch command. After that check the bundle continuity for the bundle segment

Step 5:

Apply the protective coverings as required and maintain the gap at the connector side should be minimum 25mm. save the context assembly by using save management option.

Step 6:

Create another product file for the flattening and apply the parameters as required and some parameters keep as usual.

Step 7:

Extract the geometrical bundle file in the flattening product file and maintain all the bundles as flatten.

Step 8:

Create drawing file with the size as required and apply the changes and give the mapping or annotations to the connectors and finally save the file and submit it.

RESULTS & CONLUSIONS:

· In this project we learn the wiring routing path and packaging rules of the wiring harness.

· Wiring Harness Routing is given successfully for the back door assembly and Flatten the wiring harness is also completed and finally creation of drawing sheet for the flattening wiring harness is created.

The given final project was successfully completed

.......................................Thenk You.........................