“Keeping an automotive factory in the optimum productivity band increasingly turns into a challenge,” Dirk Gorges, Member of the Management Board of Dürr Factory Assembly Systems (Dürr FAS), said at a media event held in the company’s Stuttgart, Germany, headquarters.
Dürr is one of the biggest global suppliers in the highly fragmented market for automotive manufacturing technology and services. With production volumes for individual models going down, with the proliferating number of variants, and with regionally varying market dynamics, manufacturing and final assembly become more difficult to handle from an economic point of view.
Safeguarding investment in emerging markets such as Russia and Asia demands more flexibility on the shop floor level. “Speedily setting up pilot lines, achieving fast ramp-up times and good first-run rates are goals that vehicle manufacturers pursue,” said Gorges. Traditional factory concepts with rigid layout, infrastructure, and fixed automation level do not suffice.
Hence, Dürr has translated the common necessities of final assembly into a modular approach. Called FAStplant, it is based on standardized prefabricated and pretested modules. The company says that the typical range of productivity starts from 15 cars per hour and extends up to more than 40.
Each module is a self-contained unit, made from a steel support structure and mechanically and electronically equipped with a Dürr twin-trolley conveyor system. Customized for the customer, a typical module is fitted with lighting and includes connections for compressed air and power supply lines, and provides data transfer. Ancillary equipment such as pneumatic screwdrivers also can be incorporated. With dimensions of 6.0 x 5.4 x 7.5 m (20 x 18 x 25 ft), the structure fits into standard shipping containers, and the complete module can be moved with forklifts.
DaimlerChrysler in spring of 2004 was the first to install a FAStplant module, at its Sindelfingen plant in Germany. The complete line was set up within three weeks. After testing and standardizing the vehicle assembly stages, the pilot line was then moved to the Mercedes-Benz C-Series assembly section in another building. In July 2007, DaimlerChrysler decided to move the line again. It will be dismantled and moved to yet another building where it will be stored until next usage, in February 2008.
Since its introduction, this portable factory principle has been adopted by a number of vehicle manufacturers. “About 42% of the applications are in emerging markets, with the St. Petersburg area in Russia being one highly dynamic region,” said Gorges. The development there is driven by domestic and foreign OEMs. Dürr FAS has announced that it will be involved in the $300 million General Motors plant slated to begin production late this year in St. Petersburg.
In April 2007, BMW chose the modular assembly system for its new shop in Chennai, India, where the 3 Series and 5 Series are assembled. In total, 14 assembly modules are arranged in an oval-shaped loop. The vehicles are transported from one operational cycle to the next by an overhead electrical monorail system that can handle up to 2.5 t (2.8 ton) of vehicle mass in the basic version. The installation and commissioning period at Chennai was eight weeks.
Toyota started using the modular final assembly system in November 2005 at its Valenciennes plant in France. Audi used it to set up R8 luxury sports car production at Neckarsulm, Germany, within 3.5 months. The R8 line consists of 18 modules, and its output is 22 vehicles a day. A new Ford pilot line at Cologne, Germany, was installed in May 2007 following a February contract date.
On the level of direct costs, the modular system is not cheaper than conventional assembly lines. However, modularity offers other benefits. For one, the modules are independent from building constraints. In addition, it is much easier to make adaptations, such as changed cycles or the integration of new models; an existing final assembly line can be expanded or rearranged by moving or adding modules. This freedom includes moving “monuments” such as the marriage station down the line to achieve a new optimum state.
“Even if a factory needs to be moved from one market to another, this can be done,” noted Gorges. “The modular assembly system offers the chance to enter a market with limited risk. If vehicle sales take off, the factory can be expanded flexibly. If not, it can be moved to another market.”
Compared to the time schedules of traditional projects, Dürr claims that FAStplant can save up to 12 weeks between layout release and commissioning. Maybe even more interesting to OEMs is the different quality of the planning process. Over the past three years, Dürr FAS has used digital factory planning for more than just reducing the time between white sheet and layout. “In emerging markets, for instance, our customers do not any more specify closely what is needed. Instead, we are challenged to come up with a more creative input that includes logistics and the choice of location,” Gorges said.
Dürr capabilities also include visualization. “If you can take a customer on a four-hour walk through a digital factory, this is a different approach,” said Gorges. Visualizing the assembly line long before installing it shows the interdependencies of steps, flows, and timings. Hence, bug-fixing can start as early as the digital layout stage.
This early optimization saves money, Dürr is convinced. The simulation of material flow, for example, reveals whether the number and size of buffers is correct. Wherever possible, the line thus can be downsized for the start of production to reduce capital invest. The line can be expanded later if the market so dictates. “Scalability is much needed in emerging markets,” said Gorges.
By simulating the assembly line, it is also easier to define the level of automation, according to Dürr.
Additional future Dürr FAStplant programs include a 31-module chassis line for SeverStal Auto in Elabuga, Russia. That application will help produce 15 cars per hour, 80,000 per year. Mexico is next on the road map with a modular line that will consist of 80 modules and is designed to produce an output of 40 vehicles per hour.