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ZF Friedrichshafen AG is one of the leading automotive supplier companies worldwide in driveline and chassis technology with 121 pro-

duction companies in 27 countries. The tasks of mod-ern truck transmissions today go way beyond mere power transmission: they also make sure that com-mercial vehicles are eco-friendly, economic, silent, and comfortable. With TraXon, ZF Friedrichshafen AG developed an automatic transmission system for heavy trucks that lives up to current and future needs and is ready to go into production. It is based on a compact basic transmission and a flexible modular concept. The TraXon basic transmission can be com-bined with five modules: single- or dual-disc clutch, dual-clutch module, hybrid module, motor-depen-dent power take-off module, and torque converter clutch module.

Recently, a new mixed assembly line was put into service in factory 2 in Friedrichshafen to expand the capacity and to implement the new technology re-quired for the TraXon series. The U-shaped conveyor line consists of the main conveyor comprising 34 in-terlinked conveyor line assembly stations and directly linked preassembly and commissioning areas as well

For the installation of the new assembly line, the transmission manufacturer ZF in Friedrichshafen, Germany, needed an automation concept that would take the modular set-up of the plant into account. With integrated Simatic hardware and the new TIA Portal, it was possible to meet the transmission manufacturer’s rigorous requirements concerning the line‘s fail-safety, productivity, and availability.

Flexible transmission assembly

as comprehensive tests in the process. The output can be flexibly clocked between two and eight min-utes, depending on customer requirements. Two transmission series are assembled on the new line in 500 different parts-list variations – made to order in batch sizes of one.

Comprehensive requirements

“Our main requirements on the new line were ergo-nomic design according to the latest ergonomic findings, a consistent zero-fault strategy in the pro-cess, and high output flexibility without productivity losses. In addition, the utilization rate was to be above 90% and the plant availability above 96%,” explains Rafael Kraja, assembly production planner at ZF.

In order to achieve the required optimal ergonomic conditions for the workers, the assembly trolley auto-matically brings the transmissions to be assembled into the best position for the respective processing step. There is also worker support, including a moni-tor at every workstation breaking down the task into exactly described and graphically displayed steps. ZF achieves a zero-fault strategy in the assembly process

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For Greater Efficiency and Productivity | advance 2/2013

by continuously monitoring 100% of all quality-rele-vant operating processes and material withdrawals in the entire assembly at every workstation and at every step. In addition, the higher IT control system docu-ments which processes were carried out – from torque monitoring, to poka-yoke signals, to material with-drawals. At the end of the assembly line, the assem-bled transmission is then subjected to a function test and a leak test. The system allows delivery of a trans-mission only if all the quality features are confirmed and documented as OK.

Use of proven hardware

Because of the overall positive experience, the produc-tion equipment designers at ZF chose automation technology by Siemens for the implementation. In con-sultation with the manufacturer of the conveyer drive, the Kirchner Solutions GmbH and its electronic partner Graf Automation GmbH, they decided on a Simatic S7-317 PN as the line control in combination with Simatic ET 200S controllers in the assembly trolleys as well as in the workstations and the picking shelves. A total of 120 Simatic ET 200S controllers were installed. Since

every assembly trolley is connected to a common emergency stop cycle, fail-safe interface modules are also being used. The communication to the assembly trolleys takes places wirelessly via Profinet with the Profisafe profile. For this, a radiating cable was in-stalled in the support rails. The workstation PLCs are connected via Industrial Ethernet cables.

The project team selected Simatic flat-panel moni-tors with all-round IP65 protection as monitors at the assembly stations. They are actuated by several Microbox Simatic IPC427C located in the PLC control cabinets below the ceiling. The web browsers on the PCs can be used for diagnostic purposes in order to access the web servers available on all controllers and thus display the diagnostics data of each CPU on each monitor. This continuity contributes to in-creased availability – without additional program-ming effort. A higher control system manages all the order data and parts lists.

Innovative engineering with TIA Portal

In order to effectively realize the modular, local con-cept, ZF needed a modern engineering system. The

Simatic flat-panel monitors – actuated by Simatic IPCs – specify each processing step in detail

W. G

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advance 2/2013 | For Greater Efficiency and Productivity

INFO AND CONTACT

www.siemens.com/tia-portalchristian.cd.doerner@siemens.com

Simatic Comfort Panels are used for visualization at the storage locations

The successful team (from left): Rudolf Mayer (Siemens), Ralf Klews (ZF),Attilo Graf (Graf), Rafael Kraja (ZF), Christian Dörner (Siemens)

new TIA Portal engineering framework was used for the first time for configuring a project of this magni-tude. Ralf Klews, production equipment designer in electrical engineering, was able to use the support of Siemens in Stuttgart and is convinced that the new solution will serve as a model for other similar proj-ects currently being planned. The global or project- wide storage of library projects or modules is partic-ularly helpful in modular projects of this magnitude. The master templates for hardware configurations are also useful in this context. Klews estimates a quite realistic savings potential of about 30 % in the new assembly line. Attilo Graf, working at Graf Auto-mation GmbH, agrees: “I am looking forward to using TIA Portal V12 in the future, since the configuration of the Sinamics G120 drives used here will be integrated as well. And with Simatic ET 200SP, we will have the space reserves in the control cabinet we have always wanted.”

Convincing solution

Günther Stauber, project and assembly manager at ZF, considers the company’s requirements to have

been optimally met by the new system: “The new as-sembly line corresponds to the latest ergonomic find-ings – even the employees and the work council praise the excellent ergonomics; in addition, it is a logically consistent expansion of proven principles of the ZF production system, such as just-in-time man-ufacturing, zero faults, standardization, flexibility, and employee focus.” Klews and Graf agree that the local design, safe communication via Profisafe, and, last but not least, TIA Portal with its possibilities are the keys to this success.

W. G

eyer

W. G

eyer