Intro to Vehicle Assembly Process: Let the performance begin
To this point in the process, we have worked to prepare the canvas. Now begins the work of filling it with the combination of components, options, and luxuries that will make this BMW as distinctive as its owner. This is Assembly, where it all comes together.
The body-formed, painted, and protected – waits in the stacker, arranged in order. Sequenced parts such as instrument panel, front end, and power train are at the ready in other areas of the plant. What follows is a careful and intricate performance involving the flow of parts and precisely-timed processes. From this point on, every vehicle has a name.
VIN: Vehicle Identification Number
The first step in the assembly the vehicle receives its unique Vehicle Identification Number, etched into the steel underneath the hood. More than a number used to identify the car throughout its life, the VIN serves as a unique blueprint, specifying the exact options, colors and accessories that will go into the building of this one vehicle.
Once etched into the engine department, the VIN enters the plant’s tracking system so associates can monitor its progress. Loaded onto the automated assembly build vehicle, the car begins its trop through the Assembly process.
Sunroof Seal: Every X5 – protected from above
Prior to beginning its journey down the assembly line, X5 vehicles make a quick stop at the sunroof sealing station. Here they are greeted by a robot stationed above the roof and armed with spools of an extruded rubber seal. As the vehicle moves into position, the robot heats the seal and applies it to a flange on the vehicle’s roof. The specialized automation ensures every seal is precisely fitted and reduces the possibility of leaks.
Tilt: Underbody access granted
The vehicle arrives at an area known as Tilt, so named for the specialized tilt conveyor used to transport and manipulate it. The special conveyor allows associates to rotate the body 90 degrees, providing unobstructed access to the underbody. Here, associates install fuel and brake lines to the undercarriage as well as the vehicle’s fuel tank and underbody insulation.
At this point in the line, the hinges securing the doors to the frame are separated and the exterior door panels are removed. The vehicle continues down the line to the trim stations while the door panels are routed to the door sub-assemly station. Once fitted with its electrical systems, controls, and matching interior, each door will be reunited with its vehicle further down the line.
Wiring: Thousands of connections with one way to do it
Depending on its specifications and options, each vehicle contains up to as many as 435 electrical connections. To avoid any mistakes, the wire assembly for each individual electrical component is pre-configured and wrapped by the supplier.
At the wiring station, associates first install all the harnesses that will secure the wiring. Before the wires are fitted, they are heated to between 135 and 140 degrees for 3 to 5 minutes, making them more pliable and easier to manipulate. Associates then carefully route each set of wires through the engine, instrument panel, and trunk areas as needed.
Interior: Function begins to take form
After the vehicle’s electrical infrastructure is in place, the interior begins to take its familiar shape. This happens during the process known, oddly enough, as interior. In this phase, associates working inside the car install the headliner, sound system, foot pedals, and seatbelts. At the same time, the exterior team installs the master cylinder and door seals and mounts the heater and air conditioning motor, compressor, and ventilation ducts. Note that the speed and efficiency of robots have now given way to the individuality of human craftsmanship.
Instrument Panel: Same place, same time, unique results
From the driver’s perspective, the focus of a BMW’s interior is the instrument panel, consisting of the dashboard and frame, instrument cluster and climate controls. Like so many other features, this highly customized component is unique to it’s vehicle. Depending on the model, the instrument panel is created either at the Instrument sub-assembly station located in the plant, or off-site at the supplier’s facility. Regardless of where it is built, it arrives at the Instrument Panel station in sequence and just in time to meet up with the specific vehicle for which it was designed. Associates seat the instrument panel in the car’s cabin compartment and secure it to the IP Carrier.
Seats, Seals, and Systems
The emerging BMW is now approximately 25 hours into production. Ready to be fitted with its seats, windows, and front and rear windshields. Associates, using a precision-guided sling, carefully maneuver the seats inside and align the bolt holes with the floor pan. The delivery of the doors to the rest of the vehicle is timed perfectly due to our efficient logistical network.
Once the seats are secured, robots working outside apply a precise bead of urethane sealant to channels in the front and rear of the vehicle. Special robots then carefully seat and seal the front and rear windshields in place. After making the connections for the heating and air conditioning system, associates methodically test and confirm every electrical component that has been installed up to this point.
Trim Detail: Piecing together the puzzle
Depending on the size of the vehicle being produced, there are numerous individual trim pieces. Bringing them together at precisely the right time on the right vehicle is a work of logistical genius. At this point in the process, the assembly line is not composed of intermittent stations so much as it is a continuous line of well-coordinated activity. Along this stretch, associates and robots add details such as the steering wheel, wheel well liners, trunk room coverings, and various other hatch trim pieces. Not only is the trim detail process precise and accurate, it happens in rapid succession, giving associates 103 seconds to complete each installation. Fast enough to maintain production – slow enough to make sure each vehicle receives the individual attention our customers deserve.
The line from the door sub-assembly station now converges with the main assembly line. Transported overhead, the finished doors meet up with their specific vehicle, just in time for associates to lower the doors into place and reunite the hinges. What is unusual about the process is the conspicuous absence of noise. Unlike the constant grinding and squeaking produced by chain-driven conveyors in most other auto plants, BMW employs a Heavy Elevated Monorail System (Heavy EMS) that is far less audible. All of which translates into a more relaxed and focused environment for our associates. And of course, a more precise driving machine for our customers.
How a vehicle’s drive train comes together is a story in itself. Engine, drive shaft, transmission, differential, axle assemblies, and brakes–all a perfectly balanced combination of precision and power. At the drive train marriage station, the highly engineered sub-assembly is joined to its appropriate vehicle.
Manipulated by a special transport device known as a C-Carrier, the entire vehicle is placed on a stanchion where it is lifted and positioned over the power train conveyor. As the correct power train passes below, it is carefully raised to meet the car’s underbody. A series of green lights indicates when the proper position is reached, and associates and robots bolt the two together. Once the marriage is complete, associates finalize all exhaust and under-hood connections.
Like the drive train, a BMW’s front end is intricate and its assembly is choreographed down to the last detail. By the time it arrives at the main assembly line, it is a single unit, consisting of fender, headlamps, bumper cover, front grill, and radiator supports. The individual pieces arrive from suppliers and are assembled mechanically before the doors are added. Associates mount the now unified front end assembly to the vehicle, fill the AC lines with air, mount the vehicle’s wheels and tires and a new BMW touches ground for the first time. Approximately 36 hours after beginning its journey.
Once the car’s wheels and headlights are aligned, it heads for the roll booth. During the 4-minute virtual road test, frictionless rollers on a tilting platform simulate a variety of driving conditions. Quick accelerations, uphill and downhill grades, stop-and-go traffic, and speed bursts up to 85 mph. Booth sensors monitor vibration levels in every gear and individually test each brake.
Final Inspection: Running the gauntlet
In its final inspection, each vehicle must run the gauntlet; a series of close inspections by representatives trained in Body, Paint, and Assembly. The vehicle proceeds slowly down the final 221 feet of the line. The Body Shop team measures for final fit, flushness, and gaps; the Paint Shop team scrutinizes the finish for any possible scratches; and the Assembly team adds the final touches of manuals and floor mats.
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