Networked data for the digital factory
Stuttgart, Nov 30, 2006
With the Digital Factory project, DaimlerChrysler production planners are moving in a new direction. In particular, planners of halls, body-in-white facilities, assembly lines and logistics are turning their attention to digital methods, digital processes and 3D geometries of components, production equipment and buildings. Their efforts are helping series production vehicles to reach an advanced level of development at a very early stage.
The road to the future starts in the basement — or, more precisely, in the lower level of Building 28 at DaimlerChrysler’s plant in Sindelfingen, Germany. That’s where the “Digital Factory Planning Room” is located. Here, planning specialists from all units at the Group meet to discuss the construction of new factory halls and production facilities, as well as the renovation of existing ones.
The unusual thing about these meetings is that the factory and production planners sit in a semi-circle in front of a “Powerwall” about the size of a soccer goal. Wearing 3D goggles, they immerse themselves in very realistic virtual worlds that provide them with a detailed look at the buildings and facilities of tomorrow.
This digital journey into the future begins when someone like Klemens Benz, a member of the Digital Factory Planning team, uses a control panel to turn on the six high-performance projectors that beam their images onto the Powerwall’s special screen from the rear. The screen then displays 3D images that show what a complete factory — including all production machinery — or a fully equipped office will look like when it is built someday in the future.
As an example of how the system works, Benz and the leader of his team, Peter Csavajda, like to show visitors the virtual depiction of the Van Technology Center (VTC) that DaimlerChrysler put into operation at the Untertürkheim plant in 2005. Even before ground was broken at the site, the staff at the VTC were able to see a virtual image of their future workplace on the Powerwall. The digital tour of the VTC features realistic, photographic-quality depictions that guide observers through the entire complex and show the individual offices and work areas, presenting not only desks and workbenches but also offering a view out the window to the new Mercedes-Benz Museum across the way. “What you see here is more than just an impressive 3D visualization,” explains Csavajda. “For us, the system is above all a precise, reliable, and fast tool for creating digital mockups that depict and ensure the quality of all factory components.” At the heart of the virtual system is the Microstation from Bentley, which makes possible comprehensive three-dimensional planning of buildings. Using the Microstation, DaimlerChrysler specialists then developed the FAPLIS factory planning system, the first version of which was used in 1984. These days, FAPLIS can depict and assemble all the different components of a factory in 3D.
“Simply put, what we’ve got here are digital building blocks that can be used to construct a complete factory,” Csavajda explains. “As part of the process, all of the 50 or 60 specialized areas needed to build a new factory are digitally registered in a standardized database. The really special thing about our digital planning room is that we bring people and data together simultaneously within the framework of an integrated factory planning system, and then we try to come up with the best solutions.”
> Clash detection reduces construction costs
Benz demonstrates how this works by conducting a clash detection test involving two specialized areas — steel construction and heating-system planning. The first thing we see on the Powerwall is a depiction of the building shell, with all its steel supports and pillars. Benz then pushes a button that superimposes data for the second section, and the same 3D image now also shows all heating and ventilation pipes. He clicks his mouse, and within a matter of seconds the system has focused in on all areas where planning errors have occurred.
For example, spots where a virtual heating pipe cuts through a virtual steel support are marked in a different color and are clearly recognizable on the Powerwall. In such a situation, heating system specialists and building shell planners can discuss the problem “on site” and try to come up with a solution whose details they will hammer out by the next meeting, before it is entered into the system. “It’s not unusual to have more than a thousand such collisions at the beginning of a new project — but after six to eight weeks, there are practically none remaining,” says Benz, whose planning team has digitally planned and managed all factory hall renovations for the Mercedes Car Group since 2002, in addition to its work on major projects like the VTC.
The most important requirement here is that all of the companies involved — ranging from electrical contractor firms to major suppliers of equipment — provide their planning data in FAPLIS-compatible digital form, rather than drawing up numerous individual plans for each section and then printing them on paper. Although such digital planning involves tremendous effort and considerable expense, especially in the initial phase of a new project, it is more than compensated for later on in terms of time and costs savings. In the past, a project might have been planned with an investment volume of one million euros, but that figure would increase by an average of 20 percent as a result of repeated planning changes later at the construction site. “We’ve been able to reduce these additional costs by 95 percent through digital planning,” says Csavajda.
The work performed at the Digital Factory Planning Room offers a further benefit: Every DaimlerChrysler plant has now been digitally registered by the team and can therefore be completely depicted in 3D. This means new plants and renovations to existing ones can be planned and visualized quickly, which in turn enables management to make decisions more rapidly. What’s more, construction proposals can now be submitted in 3D, which makes it clearer to authorities and the public exactly what the companies in question have in mind. Digital factory models are generally completed more than one year before actual construction begins. This means that virtual vehicles are “rolling off the line” before ground has even been broken, and the production processes to be used at the future plant are already optimized.
The complete digital implementation of not only buildings but also the entire production planning process represents one aspect of the Digital Factory (DiFa) project launched in 2001, which DaimlerChrysler is using to pursue an important goal. “From now on, no production facility will be planned, built or put into operation without digitally ensuring the overall quality of the products, production processes and the production facility itself,” says department director Rainer Eißrich.
In a situation reminiscent of the introduction of CAD systems for design and development, this approach will make it possible to use digital and 3D-based planning tools for production processes and production equipment as well. “Until now production planners have been using text and table-based programs like Excel, Access and Word,” says Sigurd Schneider of the Digital Body-in-White team. “However, planners of digital factories can employ a planning tool based on DELMIA software, which is closely related to the CATIA design software used at DaimlerChrysler. The DELMIA planning tool distinguishes between products, processes, and resources (PPR). Data from the three groups is imported from various systems and visually depicted using 3D geometries. It’s the digital linking of the groups into one system that generates the advantages here.”
Changes made by developers or assembly planners, for example, no longer have to be entered into all the sub-programs by hand in a laborious (and sometimes redundant) process, followed by the need to communicate the data to all project colleagues. Instead, changes are automatically made available to all planners after the information has been entered into the system. Staggered processes and predefined access authorization ensure that the “PPR hub” (the database) provides planners with the needed data at the right time in line with their responsibilities.
> DiFa modules already being used successfully
The DiFa team’s job is to comprehensively simulate manufacturing facilities on computers and thoroughly examine their 3D depictions before any production equipment or buildings are actually built or ordered. “This ensures that individual systems such as conveyor technology and robot cells work perfectly together, that components are transported over the shortest distances possible, and that production is undertaken with cost-effective standard equipment,” explains Eißrich.
His department is responsible for drawing up the digital planning standards and tools for central production planning, which are used to network the production processes and ensure their transparent design. To ensure that the requirements of production planners with regard to individual systems and model series are taken into account at an early stage, DiFa actually alters the design specifications of the development engineers at the interface between development and series production. For example, the current Mercedes-Benz A-, B-, M-, R- and S-Class were all planned using DiFa modules. The production planners are also already successfully utilizing their extensive software package — known internally as “DiFa Release” — for the successor generations of the C- and E-Class, and their system will be gradually introduced into the planning process for all new vehicle projects. In addition to factory and hall planning, DaimlerChrysler has for the first time — with the help of the new planning tools — digitally configured and ensured the quality of planning for the three core processes of body-in-white construction, assembly and logistics. Other processes, such as Powertrain planning, will follow.
For digital body-in-white processes, planners use the developers’ CAD data on individual components and welding points to draw up a digital production process. Here the production equipment and joining sequences are defined first, followed by the 3D layout. One goal here is to ensure that all welding points can be completed within an acceptable time period at predefined costs. That’s why the geometric data on the relevant components is provided with 3D depictions of equipment such as robots and conveyor belts (and the corresponding cost calculation). In this way, the effect of any change to a body-in-white component or process can be immediately and precisely calculated. “Accessibility analyses conducted at an early stage, and digital confirmation of the quality of welding points for the C-Class successor model, have already led to a dramatic reduction in the number of welding guns needed,” says Harald Jetter of the DiFa Digital Planning Security team.
In digital assembly planning, a work process with exact times is drawn up for every component. Up to 6,000 different work processes must be planned and checked for each model series. In addition to taking into account possible assembly sequences and cycles, the planners also examine ergonomic conditions and the strain that workers will be put under in each situation, where necessary. Using ALB (Automatic Line Balancing) software, the assembly planners then optimize assembly line volumes and the capacity utilization of all assembly stations. ALB also visually depicts the component carriers that deliver components and enables the planning of material staging areas.
The savings potential offered by digital assembly planning is enormous. “Digital planning has already allowed us to achieve significantly higher assembly line capacity utilization for interiors and chassis than is possible with conventional procedures,” says Steffen Körner, head of the Digital Assembly Planning team. “What’s more, it has done so right from the launch of production. Production costs have fallen significantly as a result.” The DiFa project group has transferred yet another core production area — logistics planning — to the digital world, and it is using its expertise here for the successor model to the C-Class. The foundation here also is a standard library containing production equipment (including carriers and transport systems), processes and transport procedures (such as “Load” or “Lift”). The library also lists the costs for each item.
Logistics planning involves combining the components needed to build a vehicle into “parts families,” each of which undergoes the same work steps from the perspective of a logistics specialist. “Planners can then draw up the supply chain for every parts family — all the way from the supplier and delivery to the assembly line to the return of empty containers,” explains Roberto Adrian, head of the Digital Logistics Planning and Process Simulation team. By allowing only certain types of logistics processes, the system supports planners in drawing up the supply chain. For example, the “supplier-warehouse-warehouse-production” chain is not permitted because it doesn’t make sense to move a part from one storage location to another. The system also allocates plant locations to the supply chain — including buildings, halls and assembly stations — thus making it possible to plan material flows. The goal here is always to move components around the plant at an optimized cost. And the results of the planning conducted in this manner can be depicted in 3D onscreen.
> Networking delivers an advanced process at an early stage
“This system also enables us to optimize the component carriers,” Adrian says. For example, if the logistics planners determine that a component carrier is not totally full because a fastening eye on the component juts out, they can talk to developers and quickly learn if the fastening eye can be designed differently. If you can load 120 components into the carrier instead of 100, you will reduce logistics costs. “In an individual case, this results in savings of only a few cents,” says Adrian, “but if you apply the principle to a volume model series, it adds up to a lot of money.”
This example also shows how digital planning can be used to network units and specialized areas that at first glance seem to have little in common. It is this networking that raises the entire process to an advanced level at a very early stage. The role of the Digital Factory project, as a kind of mediator between development and series production, is thus growing in importance. “The digital factory is a key factor for ensuring that we can successfully meet future challenges in production planning,” says DiFa director Eißrich, summing up the tool’s importance to his company.
> Virtual and real worlds
Observing the world of tomorrow today: Digital planning procedures for factory halls and buildings can depict future structures from the outside, while also providing a look into their interiors. The four images on the left are virtual and real pictures of a building at the Sindelfingen plant and employee break areas at the Untertürkheim Van Technology Center. The photo below is an aerial digital image of the Sindelfingen plant that has been projected onto the “Powerwall.” Planners can not only zoom in on each individual building; they can also “enter” it and take a virtual tour of offices and plant halls.
> Digital hall planning and error search
It used to be that mistakes made in planning for renovations or new constructions weren’t noticed until work began. Digital planning prevents such errors by running comparisons of different specialized areas to identify conflicts. For example, the computer immediately identifies all areas where a pipe would cut through a steel support. What used to take weeks to fix is now done within seconds. Such error detection is made possible by the fact that each specialized area provides its planning data in a standardized format. In this case, different pipes can be gradually integrated.
A realistic look at the factory of tomorrow
DaimlerChrysler plans to digitally register all products, production processes and production machinery in a manner similar to the one used in the area of building planning. This process has now been implemented for body-in-white, assembly and logistics planning. Experts in the Digital Factory project office develop procedures and tools that can depict not only individual assemblies in 3D but also complete production cells or even ergonomic tests (right). Three-dimensional depictions can also be generated for robot hall occupancy setups and materials transport with component carriers.
> From number crunching to 3D depictions
Complete digitization shortens the time it takes to go from an initial idea to a finished product. Planning processes used to be documented solely with tables and descriptions. Planners now supplement these alphanumeric descriptions with two-dimensional depictions that can be used to optimize assembly line cycles and material occupancy zones. The next level contains three-dimensional depictions, which provide a realistic view of the new production hall and ensure that conveyor systems and robots work perfectly together.