Process of building a passenger car (MES in vehilce manufacturing)

Normally passenger cars include family car, SUV and MPV.

Car body is the main frame of a car, is welded by steel plates, and then chassis, engine, transmission, interior are assembled into car body. The car body is welded into a cage form, to expand car space and reduce impact from outside damage.

The building process of a passenger car has 4 parts: punching, welding, painting, and assembly.

3D CAD software is used to design car body, and the 3D model is also used to design metal sheet and fixtures.

In welding process, process engineer will use 3D CAD model to design punching fixtures. The punch machine will setup fixtures and load rolls of metal sheet, and output component sheet according to the fixture. In punch shop, MES key function is to monitor real time status of devices, because its availability decides whole operation efficiency.

In welding process, robots will weld component sheet into car body. The welding quality has big impact to vehicle safety. The professional software is used to measure the gap between designed welding points and actual welding points. The welded car body will be transferred to WBS(Welded Body Store).

The key operations of welding:

1)       Welding engine cabinet, front floor, back floor.

2)       Weld these 3 parts into car frame.

3)       Weld left side and right side.

4)       Weld left/right sides into car frame.

5)       Weld doors.

Below diagram shows key components of car body:

Diagram 1.1-1: key components of car body

 

Below diagram shows key welding process:

Diagram 1.1-2: key welding process

 

In Weld shop, MES key functions is to download Orders to Lift-on stations, such as Engine cabinet, front floor, back floor, left side, right side. MES downloads Sales Orders from ERP, then generate Work Orders, and then sequence Work Orders, then downloads to machine PLCs. Machines/robots will build car components based on model type and Order attributes stored in PLC.

In painting process, a car body will take bottom painting, middle painting, top painting, and heating operations. Most operations will be operated by machines. The painted bodies will be transferred to PBS(Painted Body Store).

Painting shop has lots of process segments, most of them will be done by machines automatically, and can also be repaired by manually. MES together with PLC can deliver cars to repair areas automatically.

Below diagram shows key painting process:

Diagram 1.1-3: key painting process

 

In final assembly, car needs to install Trim, Chassis and all other components, and will run test.

Key process includes:

1)       Transfer vehicle from PBS based on route rules.

2)       In front trim line, install passenger cabinet parts, dashboard, sunroof.

3)       In chassis line, install chassis, engine, transmission.

4)       In back trim line, install tires, chairs, doors.

5)       In final line, install accessories, fill liquids, take visual inspection.

6)       In test line, write software, and test wheel positioning, lamps, gas.

7)       Building in sub-assembly lines such as doors, dashboard, engine.

In final assembly shop, most parts are assembled by manually, it relates delivery of lots of materials. MES key functions include: assembly instruction, error proofing, material pull, equipment integration.

Below diagram shows key process of final assembly:

Diagram 1.1-4: key process of final assembly

 

                Below diagram shows over all process of a car plant:

Diagram 1.1-5: over all process of a car plant