The stamped body panels are locally heated or simultaneously heated and pressurized to form a body assembly. Spot welding is the most widely used in automobile body manufacturing, and the quality of welding directly affects the strength of the body.

The automobile body is a structural part composed of thin plates. The stamped sheet metal is assembled and welded to form a body shell (body-in-white), so assembly and welding is the key to body forming. The assembly and welding process is the main part of the body manufacturing process.

The car body shell is a complex structural part, which is composed of more than a hundred or even hundreds of (such as cars) sheet stamping parts connected by welding, riveting, mechanical connection and bonding methods. Since most of the body stamping materials are low carbon steel with good welding performance, welding is the most widely used connection method in modern body manufacturing.

General assembly is the process of assembling the body, engine, transmission, dashboard, lights, doors and other parts of the entire vehicle to produce the entire vehicle.

a. Automobile assembly concept and its characteristics

Automobile assembly is the final link of the entire automobile manufacturing process. It combines tens of millions of parts of various types that have passed the inspection, according to the specified accuracy standards and technical requirements, the component assembly, the assembly, and the entire vehicle, and the strict Inspection procedures to confirm whether it is qualified. Automotive products require good power, economy and durability to achieve the carrying function in a variety of complex environments. Modern automotive products require safety and reliability, beautiful appearance, comfortable ride and meet environmental protection requirements. These requirements are ultimately guaranteed by the assembly process. If the assembly is improper, the qualified parts manufactured at an expensive price may not be able to install a qualified car. Therefore, assembly is an important link to ensure product quality. Automobile assembly is characterized by many kinds of parts, large quantity and complex operation content. In addition to the engine, drive train, body, suspension, wheels, steering system, brake system, air conditioning system, etc., assembly parts also have a large number of interior and exterior trim parts, electrical appliances, wiring harnesses, hoses, hard pipes, glass, Various types of oil filling, etc. Automobile assembly workload accounts for about 20% ~ 25% of the total manufacturing workload, and its operation includes interference fit, welding, riveting, inlay, piping, wiring, threaded connection, various oil filling, etc.

B. Assembly method

1. Threaded connection method

Screw and bolt connection is the basic method of mechanical assembly. It accounts for about 31% of the workload of automobile assembly operations. Manual wrenches are used for thread connection in individual parts. The more common ones are pneumatic wrenches or electric wrenches and electric screwdrivers.

2. Bonding method

For the parts to be bonded, the interior parts generally have gaskets, sound insulation materials, door interior trim panels, and exterior parts generally have windshields, lights, signs, etc. Bonding method: small parts are coated with adhesive on the body in advance, while large parts are coated with adhesive directly on the parts that need to be installed.

3. Filling method

It refers to the method of various liquids such as engine oil, transmission gear oil, radiator coolant, brake fluid, power steering hydraulic oil, air conditioning refrigerant, windshield washer fluid, fuel oil, etc. during assembly.

c. Assembly equipment

1. Ground conveyor (shallow supporting chain)

2. Elevated aerial suspended conveyor

3. Plate conveyor chain