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Continental Timisoara: The first fully PC-controlled factory in the world

All-round control with IEC 61131-3

The tire manufacturer Continental AG successfully uses PC-based automation in its production facilities around the globe. Europe's most advanced mass-production tire factory was recently built in record time in the Rumanian town of Timisoara. The new manufacturing facility cut installation and commissioning costs in half using PC control compared with traditional PLC-based technology. All production machines and systems at the Timisoara tire plant are equipped with Beckhoff control technology.

Continental AG with head office in Hanover (Germany) is a worldwide leader for brake systems, chassis components, vehicle electronics, tires and technological elastomers, with sales of 11.4 billion euros in 2002.
The company currently employs around 65,500 people worldwide, of which approximately 27,000 are based in Germany.

Tire production in the Continental plants is highly automated, but not without manpower. This is one of the reasons for the increasing trend to relocate tire production plants in low-wage regions. On the other hand, it means that very powerful and intelligent human-machine interfaces (HMI) have to be implemented in the production machines. Additional factors are cost and system benefits, for example via integration of the visualization and the machine control on the same controller.

The supplier relationship between Beckhoff and Continental AG goes back to 1996 and has developed into a global success story. The highlight of this successful cooperation so far was the opening of the car tire plant in the Rumanian town of Timisoara in October 2000, which is still regarded as Europe's most advanced factory for the mass-production of car tires.

The new tire factory in Timisoara was built to different standards than those used for many traditional production plants. To date, approximately 100 million euros have been invested. The plant was designed for an initial annual capacity of 6.5 million tires and built in record time. The location was chosen in mid-1998, design and engineering work started at the end of that year. The foundation stone was laid in February 1999, and the first machines were installed at the end of that year. Production officially started on 20 October 2000, and the plant was certified according to ISO 14001 and EMAS in mid-April 2001.
To date, the following production stages and systems have been realized at Timisoara:

	Preparation with extrusion lines and cutting machines;
	Assembly of green tires with individual machines using highly dynamic and automated processes;
	Vulcanization for shaping under high pressure and temperature in heating presses;
	Fully automatic test machines and visual inspection benches;
	Complex conveyor systems.

The factory is currently being expanded for a much larger production capacity. The plans include the construction of a mixing room and a calender facility for producing crude rubber blends and steel or fabric plies for tire production.

Standardized machinery

The production plant is equipped with state of the art machines and systems and designed for maximum productivity. The main aim for the design of the control system was the use of standardized machinery to ensure continuity and uniformity.For the whole Timisoara plant, Industrial PCs, fieldbus components and servo controllers from one supplier were chosen as the control technology for all production facilities.

The requirements for the PC-based control technology were clearly defined, including high speed, availability, and simple handling of the control components. Accordingly, the first applications were developed and programmed jointly by specialists from Continental AG and Beckhoff staff. Once the hardware and platform issues had been clarified, the Continental AG staff responsible for the project prepared guidelines for writing the application software that were binding for all suppliers.
These guidelines are universal, in the sense that they were subsequently also used at other plants.

Uniform PC Control

All production machines and systems at the Timisoara tire plant are equipped with Beckhoff control technology. Over 230 IPC controllers are used, plus more than 250 servo axes. Networking is via various bus terminals and bus couplers for the Beckhoff Lightbus and Profibus DP. The operating system for the PC controls is Windows NT with the Beckhoff real-time kernel and different levels of the TwinCAT automation software (PLC, NC PTP). TwinCAT PLC offers all the languages in the IEC 61131-3 standard. It contains a powerful 32-bit development environment for programs whose code size and data regions far exceed the capacities of conventional PLC systems. Compared with traditional PLC-based automation of the manufacturing facilities, the PC control technology saved a total of approximately 50 percent of investment, installation and commissioning costs.

The PC technology enables globally accepted standards for hardware and operator interface design to find their way onto the production floor. Furthermore, the complete diagnostics concept was realized using state of the art technology. For instance, the extrusion and cutting equipment features camera systems that store the results of continuous width measurements in order-related databases. These data are analyzed in networked quality management workstations.

Spare parts management also benefits from PC-based control technology: only two types of Industrial PC are used at the Timisoara plant. In the harsh vulcanization environment, a compact Panel PC controls the tire heating presses. A control cabinet PC is used wherever high performance for complex machines, systems, and NC controls is required. With this, the hardware is compatible and the software can be ported at any time. In addition, all safety aspects that are relevant for the PC control technology have been considered, so that even unforeseeable sources of malfunction such as power failures do not cause problems. The motivated Continental team with the ability to think unconventionally, and the determination to use state of the art machine technology has contributed significantly to the success of the project.
This strategy obviously involves also modern IT and associated flexibility, including, for example, the retrieval of machine data via web-based technology using standard web browsers through a hierarchic structure with access rights. Another option is access via intranet from the production machine to recipes that are stored in the recipe server for certain products. IT coupling is very important, since tire production is documented throughout.

The company-wide tire information and control system use approximately 150 Industrial PCs. With this, each individual production step can be recorded and documented, irrespective of the degree of automation and the control technology of a production machine. In this way legacy technologies can be included. These legacy technologies are used in older machines, which can be based still on electromechanical or relay technologies.

Value enhancement is the yardstick.

One characteristic of the tire business is the high degree of sensitivity. For instance in motor racing, the current contest between the teams is more like a tire war rather than a question of engine or chassis superiority. One of the main success factors for the cooperation is the commitment to open system architectures and internationally recognized standards.
This applies to all aspects, such as the hardware (e.g. the Intel-based processor technology), the operating system (Windows), the programming according to IEC 61131-3, and the open communication technology.