Manufacturing the Mini
That the Mini is an icon is beyond dispute. The original was a car of its time: compact, basic and cheeky. Everyone loved it from the young to the old, from the impecunious to the fabulously wealthy. It was the people’s car, more so than even the Beetle. And yet, tempus fugit, its time had really run out, perhaps even 20 years ago, but it was still manufactured because people kept buying it. Ending production was more like putting a good and faithful dog to sleep, the emotional pull too much.
Then BMW came on the scene and bought Rover, Mini’s owner, in 1993. It turned out to be a disastrous move for the German automaker, but if this cloud had any silver lining, it was the Mini. At first, it was left to the British design team to come up with some ideas, but those presented in Geneva–Spritual 1 and 2–were wide of the mark of what a Mini was all about. Then the Germans got heavy. While lip service was paid to British sensibilities, responsibility for the new Mini was transferred to Munich, and the result is...sensational.
Now there are those who will say that the new Mini (BMW, in its logic, spells this little car in capital letters) has missed the original concept by miles. It may look Mini-ish, but it is far too large and bloated ever to wear the Mini name and that Alec Issigonis, the original’s creator in 1959, would be turning in his grave. That is a moot point, as reactions of more people indicate it is going to be a huge success.
Now that is very good news for the folk at Cowley, the original Morris works–since 1914–on the outskirts of Oxford in England. This was a plant whose very future was in jeopardy a few years ago. BMW, though, saw its potential and invested hundreds of millions of dollars in it in a thorough rejuvenation program. However, that was for the Rover 75, a car that was launched toward the end of BMW’s ownership of Rover. Once it was announced that the British automaker had been sold for £10 last year, Cowley’s future suddenly looked bleak again, and yet it turned out that it was not part of the deal–it still belonged to BMW and it was going to make the new Mini.
Before it could turn its hand to that, though, there was the small matter of transferring all of the Rover 75’s presses to the Rover-owned plant in Longbridge, about 100 miles away, and installing the new presses in their place. However, this was done without fuss and fury over a four-week period last summer–but it had to be as the decision to switch production from one plant to another was made just nine months before pre-production was due to start and 12 months before series production.
“We did it on time and within 10 weeks we were into volume production,” says Paul Chantry, Body-in-White director at Cowley. “Normally we reckon to take six months for this.”
Once the transfer had been made, BMW then spent around $400 million further upgrading the plant and introducing innovative systems such as KISS (Kernfertigungs – Integierendes Steuerungs System). KISS is a BMW Group information technology system that totally automates communications throughout the production process and provides an electronic history for each and every car produced. From body-in-white to the end of the assembly line, KISS schedules and sequences production.
Another innovation at Cowley and a first in Europe was the introduction of electric and battery tools in place of compressed air tools on the assembly line. These are also linked into the KISS system so that their performance can be monitored through a controller station. Not only do these tools give far greater accuracy and finer tolerances, but the working environment is altogether more pleasant as the noise level is dramatically reduced.
These are just two tools in BMW’s quest in the “zero-fault” quality program it is instilling in the workforce. “If you plan for zero defects,” says Assembly director Rainer Bickmann, “there is a good chance you will get zero defects. If you don’t aim for zero, then you’re pretty certain to get some.”
Around $280 million was spent in the body-in-white facility on renewing and expanding it to 40,000 m2 for the increased levels of volume and automation. The body-build process is highly automated with 229 KUKA robots accounting for 80% of all robotics with the remaining 20% being sourced from in-house toolmakers within the BMW Group. The spot welding is 100% automated. Laser inspection is carried out by Perceptron cameras at key points of the build process to check the build integrity during manufacture on-line and also quality sampling off-line. The body shell itself is said by BMW to be class leading in its stiffness, which at 24,500 Nm/degree is some two to three times stiffer than any of its rivals.
As customers can order their car with a contrasting roof color in white or black, the paint shop, which was built in 1997, features Mini-Mix and Micro-Mix paint systems for fast color changes between individual body shells. An eight-stage process, it eliminates the need to “batch” paint a number of cars in the same color before switching colors. The total time taken to protect and paint the body shell is 10 hours.
Painted bodies are received in a sequencing store above the final assembly lines where the first stage is to remove the doors, which then pass along their own sub-assembly line at mezzanine floor height to be trimmed. The body itself is lowered to the main hall and onto individual wooden skillets that form the moving assembly line. These allow the body to be raised and lowered for different assembly processes while being wide enough for associates to work on the car as it moves down the line. The skillets stay with the car until the wheels are fitted toward the end of the production process.
The car’s barcode is read by KISS at every assembly stage, eliminating the need for the traditional vehicle history card and providing a direct electronic link with the production control system. Each car is also fitted with a transponder that ensures immediate identification and tracking at any assembly station.
Throughout the assembly process, special attention is paid to the ease of handling parts, with the use of assistors in tasks such as the sunroof, exhaust system and battery installation. The height of the car on the assembly line alters to provide optimum working conditions for associates and for one assembly sequence the car is rotated through 90° on a swivel mounting at waist height to give easy access to the underside. Altogether, 2,415 different parts are fitted on the car on the final assembly line.
The cockpit and instrument panel comprising the complete facia with steering wheel, steering column, instruments and controls, heater, and wiring harness are assembled as a single unit into the car. Given just a six-hour notice of the required specification, the cockpit arrives from Magna to the appropriate point trackside without any manual handling from the time it is dispatched from the plant at Redditch 60 miles away to fitment. Altogether, there are 10 just-in-time suppliers responsible for 45% of all Mini parts.
The 4-cylinder engines, which come from the BMW/DaimlerChrysler joint venture plant in Brazil, are dressed in a sub-assembly area according to specification and clutch, gearbox, front and rear suspension assembly takes place on four lines.
After the tire sequence check, which checks that the correct tires have been fitted, the final assembly process includes complete test procedures with electrical systems testing, water test, and parts quality control. There is also the final finish line with a “buy-off” point where the completed car passes from the manufacturing activity to the sales organisation.
The plant has a fully installed capacity of around 100,000 cars per year based on a two-shift system. This year, though, it is expected to produce no more than 30,000 vehicles. Between 1959 and 1968, 602,817 Minis were manufactured at Cowley, with a peak output of 94,898 cars during 1966/67. BMW and everyone at Cowley will hope to emulate, if not beat, this record in the years to come.
According to Kunihiro Hoshi, chief engineer for the GX 470: “Three of my top goals were to create a body-on-frame vehicle with sweeping off-road performance and unibody-like on-road capability, and, of course, it had to meet the Lexus quality standard.” He met his goals. But why would anyone want to bang this vehicle around on rocks?
Many countries who once were major players from a vehicle production/export perspective are finding it difficult to even find their niche today.
By James Gaffney, Product Engineer, Precision Grinding and Patrick D. Redington, Manager, Precision Grinding Business Unit, Norton Company (Worcester, MA)