Transparency All Along the Line
In an international project, the first of three of the world's largest suction transfer molding presses has come into production at Audi Ingolstadt. Siemens has been working closely with press manufacturer Schuler for a long time, and they have implemented a homogeneous control and visualization solution, based on Simatic®, which is both comfortable and efficient.
Schuler Pressen GmbH & Co KG (Goppingen), the Schuler Group's leading mechanical press systems company, is a global market and technological leader in the metal forming sector and, as a system supplier, offers production equipment, tools, and procedural knowhow for the entire metal processing industry under one roof.
The suction transfer molding press for Audi Ingolstadt is part of an international Schuler project, which also includes two further systems of the same design for Audi Neckarsulm and VW do Brasil, as well as a simulator with an identical HMI system at Schuler Automation in Gemmingen. On the simulator, the pressing processes are programmed, optimized, and then transferred to the various sites.
The blank loaders for the three systems also come from Gemmingen. The project also involves Prensas Schuler S.A. Brasil (PSB) in Sao Paulo. PSB supplies components to the Group companies as well as complete production systems to end customers.
Large Components In a One-Minute Cycle
The 75 m long production line is made up of one blank loader and six working stations for forming, edging, and cutting out large vehicle components weighing up to 30 kg, such as side bodywork panels, doors, longitudinal beams, wings, engine hoods, and roofs. A special feature of the system is that it can process either steel or aluminum blanks.
The section of the project at Audi Ingolstadt also includes a discharge station and a training press similar to the production system, which is used to train new staff and for training on new tools.
Cooperation In Automation Technology
Schuler has been working successfully with Siemens for a long time in the area of control and automation technology. The reasons for this are the global presence of the two partners, the scalable standardization and availability of the systems, and the comprehensive service offered. Based on positive experience in similar projects, including at VW Shanghai, Schuler decided to use standardized control and automation systems from Siemens in its suction transfer molding presses.
On the one hand, nine Simatic S7-400 control systems were linked to a high-speed industrial Ethernet network, on which the visualization of the system using Simatic WinCC (Windows Control Center) runs. On the other hand, in a star-shaped Profibus DP network, they communicate with a master controller, as well as with around 400 distributed ET200 peripherals, 60 Profibus absolute value sensors, and a further 9 DP/AS interface links.
This separation of the buses into SPS and PC networks is typical for Schuler and makes diagnostics on the complex system considerably easier.
WinCC -- Open Standard For Transparent Processes
To operate and visualize the process, Schuler transferred its tried and tested press control system into Simatic WinCC, assisted by a programmer from Siemens.
At the heart of the system is a central WinCC server in the control room, on which all information converges. The redundantly designed PC has external mirror hard disks, which means that the 10 connected WinCC clients at the stations on site or in the control room can always access identical, consistently updated data.
The advantage of the client/server structure is that process displays can be edited on all stations, are centrally stored, and are immediately available throughout the system. Around 3,000 pictures describe every last detail of the system and guide operators safely through the process. Using the WinCC "User Archive" option, Schuler has integrated a tool data catalog for around 200 different tools, which provides the relevant setting data at the touch of a button -- including the data for the NC-controlled floor operating devices. The visualization system has direct access to the data from the Simatic controllers, a feature that most competing products do not offer, or only offer to a limited extent.
This comprehensive access is particularly beneficial in simplifying fault location -- another crucial reason for the use of the standardized automation technology from Siemens. For maintenance and servicing, access is possible from any point in the system with a single programming device, thanks to new Simatic functions (routing). WinCC allows the display to be switched to any of the language versions installed at the touch of a button (without restarting).
This allows the service engineers to use the German user interface for remote maintenance, while the operators on site -- at VW do Brasil, for example -- can see exactly the same content in the Portuguese version.
SCCMS -- Integrated Deep Drawing Knowhow
In order to maintain relatively soft sequences of movements that do not damage the machine, even with moving masses of up to 30 tons and plunger speeds of up to 500 mm/s, the Schuler press specialists have developed a method that moves the die cushion downwards shortly before the top part hits it, thus damping the impact. The operation and visualization of this pre-acceleration, along with other methods that are relevant for the process, are integrated in the Schuler Cushion Control and Monitoring System (SCCMS) and implemented in Simatic WinCC.
Tried and Tested Teamwork
The Audi Ingolstadt project has been completed successfully, and the press is now supplying large components for around 2,000 Audi A3, A4, and TT models per day. With support from Siemens, as an international partner for control and drive technology, the identical systems in Neckarsulm and at VW do Brasil have also been delivered on time.
With consistent standardization of the presses using Siemens products and strict mechanical and electrical decentralization, Schuler can have not only distributed production but also distributed commissioning of the systems, making the company more flexible and faster to respond all round. Furthermore, thanks to the comprehensive nature of the Simatic world, the training costs for both the manufacturer and the user are reduced to a minimum.
