A clever combination
Windhoff avails itself of the advantages of combining electrical engineering and fluid power in developing rail vehicles
Windhoff Bahn- und Anlagentechnik GmbH avails itself of the advantages of combining electrical engineering and fluid power in developing rail vehicles: The CAx systems of EPLAN for the two disciplines are perfectly harmonized. Thus, it is possible, for example to develop electro-pneumatic breaking systems while requiring little time and with a minimal risk of errors. Whereby Windhoff uses a modular system that also accelerates the design process. Anyone who often travels by rail will be familiar with the rail vehicles of Windhoff Bahn- und Anlagentechnik GmbH in Rheine, Germany, even if he does not have the pleasure of traveling in such a vehicle. For Windhoff – a company of the Georgsmarienhütte group – develops and manufactures rail vehicles for repairing trackage and catenaries, for example for grinding or maintenance of rails as well as special vehicles such as fire-fighting and rescue vehicles, rail vehicles for cargo or switching locomotives. A further division manufactures stationary system for rail technology such as lifting platforms, a third division has specialized in systems for industrial technology. Windhoff rail vehicles are in demand worldwide – currently maintenance ve-hicles for a Dutch high-speed track, fire-fighting vehicles for the Swiss railways and maintenance vehicles for a high-speed track in Taiwan are being manufactured in Rheine.
Order-specific production – modular development
The vehicles are generally produced order-specifically. The differing specifications of the individual rail companies for themselves ensure that Windhoff cannot use "ready-made" developments. The approximately 15 to 20 employees in the design team therefore have a lot to do. Andreas Hellweg, graduate electrical engineer at Windhoff: "In order to accelerate work and improve the quality, we began a few years ago to conceive modules that only still have to be adapted to the individual requirements."
Electrical engineering and fluid power: Planning from the same mold
In the course of this development Windhoff took the decision to use fluid-PLAN (now EPLAN Fluid): This CAE system simplifies planning the fluid power considerably and furthermore runs on a common platform with EPLAN 5 (new: EPLAN Electric P8) for electrical engineering design. Verena Köster, drafts-woman for electrical engineering in the rail division: "Our aim was and is to modularize the design by functions. In this respect the closest possible connec-tion of fluid power and electrical engineering makes sense, since the fluid-power systems in our rail vehicles are almost always controlled electrically. In addition the procedures used in designing are very similar." Verena Köster is an excellent judge, since she originally worked exclusively in electrical engineering design and now spends 50% of her time on fluid power.
New procedure: Disciplines are handled in parallel, not consecutively
Previously, the designers used take drawings from projects that were as simi-lar as possible as the basis and then modify these to suit the individual require-ments. Now, they can first call up a project-neutral template project, for example for the "crane" function. This module contains one modular unit each for the fluid power and electrical engineering. The modular units are developed in parallel, whereby the relevant changes carried out in the one are automatically transferred to the other. Verena Köster: "This allows electrical and fluid power personnel to work in parallel on a project: Thus saving development time." This is an important factor for Windhoff since both the development and production departments have enough to do.
Common development promotes communication
Great value is placed on having identical schematics for the two disciplines, up to the number of pages and the numbering of the components. But it even goes further: Development is really carried out together – what used to happen in two departments, in separate rooms, is now carried out in close cooperation, with a corresponding positive effect on the result. Andreas Hellweg: "The common de-velopment of fluid power and electrical engineering lets us reach the target faster and promotes the modular development. The introduction of fluidPLAN made rethinking and a different way of working necessary."
Initial skepticism overcome
This was true for both the fluid power design and production. For them the change was definitely a greater change than for the electrical engineers. But they rapidly also learnt to appreciate the advantages offered by the close cooperation with the electrical engineers, especially since many Windhoff suppliers, such as the manufacturer of the loading cranes, also use fluidPLAN: Which simplified the work. And while there sometimes used to be coordination problems between the hydraulics and electrical engineering design teams – in the period when the me-chanical design team was still responsible for the hydraulic system – for example about the placement and connection of components, these problems are now a thing of the past.
Verena Köster, drafts-woman for electrical engineering in the rail division: "Our aim was and is to modularize the design by functions."
A common scheme
This is the reason why all the current projects at Windhoff are created with EPLAN 5.70 and fluidPLAN – and the designers expect further advantages from the new EPLAN Platform. The licenses have already been bought for EPLAN Electric P8 and for EPLAN Fluid, but implementation will not be started until April. August Teepe, IT head of the Windhoff rail and plant technology: "In our company the CAD systems – including the mechanical design – are linked via the EDM system of keytech to the SAP system. We have thus implemented a consistent data flow from the first design drawing through the detailed design to the commercial de-partments: For example, keytech generates bills of materials directly in the SAP system, which the purchase department then uses directly as the basis for the or-ders." Since the provider of the EDM system will not have completed the interface for the new EPLAN Electric P8 until the beginning of the year, the company has decided to wait and shortly implement the interface to SAP directly in order to maintain the continuous data flow.
Fluid software for compressed air, hydraulic oil and water
The Windhoff designers also use fluidPLAN to design the pneumatic systems. The pneumatic components of the rail vehicles include, for example, the activa-tion of the pantographs, the brake and the signaling as well as further control sys-tems. In addition, the software is also used to design the oil hydraulic units such as the water supply to the rail grinding systems.
Railroad control systems/braking systems: Close interconnection of the disciplines
A particularly intensive development area are the very complex railroad control systems that differ depending on the respective nation and railroad company. The documentation of a system / rail vehicle may encompass several hundred pages of electrical engineering as well as several pages each of pneumatic and hydraulic units. This too documents the close link between electrical engineering and fluid power that Windhoff has now also implemented on the design level. This also applies for the braking module that the designers have developed them-selves: Here all the pneumatic and electrical components are combined on a compact module.
Day-to-day work made easier in many respects
Windhoff sees further advantages in using fluidPLAN, or in future EPLAN Fluid. Verena Köster: "The CAx connection of electrical engineering and fluid power fits well with the new standard for items, EN 61346, that structures the device tags uniformly and across disciplines by their functions. In addition the direct connection to databases, such as the online catalogs, saves a lot of time." Sensor components, such as temperature sensors in the hydraulic reservoir or pressure sensors in the lines are also easier to include in the design, since they have to be included into the module both with the fluid power and electrical engi-neering elements. The data supplied by the sensors are then processed further in the PLC of the respective system. And for fixed combinations, such as proportional valves and their actuating units, the draftspersons have stored macros that they call up at the click of a mouse button.
A logical connection
Thus the connection of electrical engineering and fluid power has proven an advantage for designing in many respects – Windhoff registers both more effec-tive work processes as well as fewer inconsistencies between the various disci-plines. These advantages will become even clearer when the new EPLAN plat-form is installed in April: Then both disciplines will be using exactly the same data basis and, put simply, will each form a different aspect of the overall design.
