As European car makers face increasing pressure on profits, they are keen to run their plants as efficiently as possible, wringing the maximum capacity from them. In its factories in Sunderland and Barcelona, Nissan has achieved this by producing several different models on shared production lines.
Other car makers such as Volks-wagen and Renault have plants that produce several variants on a common platform. By contrast, at its Sunderland plant Nissan produces three distinct volume models on two production lines, having just added the Almera medium-sized hatchback to the smaller Micra and larger Primera. In Barcelona, it recently introduced the medium volume Almera Tino, a competitor for the Renault Espace, in a plant producing four other models.
Though the problems of accommodating the new models were different at the two plants, common factors included efficient use of space, sophisticated production planning systems, and a flexible workforce.
Nissan’s plant in Sunderland began making the Bluebird, later replaced by the Primera, in 1986. The Micra was added in 1992. `With the Almera,’ says Colin Lawther, engineering general manager of Nissan Motor Manufacturing UK, `we faced the challenge of shoe-horning a third model, within tight budget constraints, into a two-model plant.’ Sunderland was already Europe’s most productive car factory, though once again last week the company sounded dire warnings about future investment being in jeopardy because of the strong pound.
The Almera had to be introduced without disrupting existing production. The plant is expected to produce 350,000 cars this year, up from 271,000 last year. Investment in the new line was £250m. Nissan recruited 800 new workers.
Space and funding constraints necessitated creative solutions. In the body shop, for example, Lawther says `the easiest solution would have been to add a third line’. Instead the Almera and Micra share a line.
Production is organised as follows: First, the engine bay structure is assembled off-line. The details of the car model are entered into the computer production planning system from the start – whether a Micra or Almera, three or five-door, and level of trim. This information is transmitted to robot welders on the main body line, which complete the body assembly and can cope with models in any sequence.
From here the bodies go to the paint shop, where two booths deal with Primera bodies and two others deal with the Almera. The Micra is shared between all four booths. Computer control is used to maximise runs of consecutive bodies needing the same colour.
Next, the painted bodies go to the chassis and trim shop, where final assembly of the Almera and Micra takes place on the same line. Here, says engineering manager Nick Miller: `We wanted to put the Almera on one line, so we had to move some Micras on to the Primera line.’ This process began early last year.
Improving plant logistics
Parts for two cars now had to be accommodated at the side of each line. `We had a lot of Kaizen activity to free space and fit racks at the same time as reducing inventory,’ says Lawther. `We achieved a massive improvement in parts logistics: 30% compared with the normal rate of 5-10% a year.’ Again the computer production planning system comes into play. Instead of the printed build sheet which was previously fixed to each car the system automatically indicates to the worker at each station which parts to fit.
Not only do the two cars have different parts, but they are assembled in a different order as well. This entailed considerable planning to enable different operations on the two models to be done at the same place along the line in the same amount of time.
In addition, since the newer Almera uses more modular components, off-line subassembly areas had to be created to harmonise dissimilar operations.
Training was a big issue. Each Nissan worker can normally do at least three jobs on the line. With two models, each had to learn another three on the new model. At the same time, the new workers were being recruited. At launch, Nissan aimed for each new recruit to be able to do just one job on each model at the standard line speed.
Nissan’s Iberica plant outside Barcelona faced a similar challenge. The company’s first European factory, it began by producing the 4×4 Patrol in 1983. It still supplies around 3,500 of these vehicles to the Spanish police every year.
To this was added, in 1984, the Vanette Cargo, a Ford Transit-sized van. The Serena, a multipurpose vehicle derived from it, followed in 1992. A year later came the Terrano II sport-utility vehicle. In May the Almera Tino – the first Nissan passenger car to be produced in Spain – was introduced. It will swell last year’s total production of 77,122 units by 25,000 this year, and twice as many next. The e180m (£112m) investment created 600 new jobs.
`With the production of the Almera Tino the Iberica plant will be manufacturing simultaneously five very different models,’ says Alfonso Diez, senior manager for human resources. Between them, they encompass different drive arrangements – 4×4, rear wheel drive, and front wheel drive in the case of the Almera Tino. They are different structurally, with a separate chassis in the case of the 4×4 models, while the others have unitary construction.
Asked why the Barcelona plant was selected to produce the new model, Carlos Morant, Almera Tino project manager at Nissan Iberica says: `This plant is very good at medium volumes. Sunderland is set up to produce hundreds of thousands of units. This plant is more aligned to niche products, which are also more complex.’
Rather like the situation in Sunderland, however, production of the Almera Tino body was incorporated into the existing body shop lines. After some initial subassembly operations, the Almera Tino joins the Terrano II line to have its floor pan and body side panels assembled by robot welders. It then transfers to the Vanette/Serena lines to have doors, bonnet and tailgate added.
Door frames and skins are stored at the side of the line as separate pressings and are only assembled as needed, as a means of saving space. Only one press is used for all four of the Almera Tino’s doors, as opposed to one for each. Doors are made in batches of eight, with a quick change system changing the die in under a minute. This saved 500m2 of floor space, says Jordi Zabaleta, senior manager for production engineering.
After being painted, the bodies go to the final assembly shop where, in contrast to Sunderland, the 4×4 models, the Vanette/Serena and the Almera Tino all have separate lines. But Zabaleta believes the Almera Tino line sets new standards in flexibility.
Fast and flexible production
There are no areas where the conveyor is elevated. Instead, pits in the floor are used for operations which have to be carried out from underneath. Martinez argues that it is easier to board over a pit than modify a conveyor if the line has to be reconfigured.
For operations such as fitting the rear axle, moving platforms called `pirate boats’ are used. These carry the worker and all the necessary tools and equipment to fit the part. A similar platform carries the part if it is heavy or unwieldy. The boats move at the same speed as the line, and return to their starting point when the operation is completed. Since there are no obstacles, the start and stop points can easily be reprogrammed if necessary. `Nothing is fixed to the floor,’ says Zabaleta.
Again training was important. In the run-up to the start of production 300 workers were sent to Japan for up to three months to train in the pilot Almera Tino production plant.
In both Sunderland and Barcelona the training and planning seems to have paid off. In both cases a very fast increase to maximum production speed was planned.
In Sunderland, the start of Almera production was fixed by the Christmas/New Year shutdown and had to hit its maximum rate within six weeks to build up stocks for the spring number plate prefix change. The Almera Tino began production at 49 vehicles daily on 15 May; by 23 June, it had hit the target of 190 a day. That’s just six weeks to hit full production – about half the time normally be expected in the industry.
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