Manufacturing products-to-order is a challenging production management problem itself. Imagine building automobile engine/axle assemblies in 180 possible configurations that must be delivered within three hours to the customer in an exact sequence. That challenge would be bad enough, but the builds are not manufactured and assembled in large lots. Manufacturing is one assembly at a time with the builds interspersed according to the production schedule at the auto manufacturer customer’s plant.
This is the challenge facing production managers at the ZF Lemforder plant in Tuscaloosa, Ala. They must accomplish this task with 100 percent accuracy in order to keep their customer, luxury carmaker Mercedes, happy. But it’s not enough to just deliver the engine/axle assemblies on time in the correct sequence. ZF must also provide documentation for each engine. Failing any of these requirements would stop the Mercedes production line, resulting in a large charge to ZF for each minute the line is down.
Because not every build will be completely correct and the tact time (time to assemble) is about 70 seconds, ZF needed a way to keep track of what assembly is being pulled from the line and where it can find that same assembly that can be pulled ahead, thus maintaining the proper sequence of assemblies.
To accomplish all these tasks, ZF uses a set of components from Siemens Energy & Automation, based in Norcross, Ga. The set, dubbed Totally Integrated Automation by the vendor, consists of a Siemens Simatic programmable logic controller (PLC), WinCC human-machine interface and SimaticIT manufacturing execution system (MES) software. The MES provides communication between the factory floor process and the enterprise software from SAP AG, of Walldorf, Germany. Both Mercedes and ZF use SAP, a fact that enhances intercompany communication of orders and shipment information.
The process begins with production orders from Mercedes’ SAP implementation sent to ZF’s SAP implementation. Orders contain such information as build codes and sequencing. This information is sent to the SimaticIT execution system. This application ensures that orders are pushed through in correct order. It also handles system upsets—this is the application that, when notified of a product that must be diverted to repair, finds another build somewhere in the physical system and gets it inserted into the sequence. The system tracks orders against both tact time and delivery time, as well as when the order is placed and when the truck leaves for the customer. It also captures the product genealogy and build history. The ability to accomplish this part of the system is considered a ZF competitive advantage. While the MES captures all of this information and formats it for communication to the ZF SAP application, the axles are aligned, assemblies are completed, staged and shipped via tractor-trailer rig to the customer’s plant.
Manufacturing to enterprise
The MES pushes complete quality and “as built” information to the ZF SAP application, which in turn forwards it to the Mercedes SAP application. The assemblies are received at the customer site and put on a conveyor that connects directly to the assembly line. Then a worker scans a bar code label from the build and sees all the information on a screen at the assembly station. If the operator does not see all the correct information, the line is stopped and ZF gets a bill. The key to the entire process is the role played by SimaticIT MES.
The MES together with an integrated DCS is a great enabler to make a complex process simpler and more accurate.
According to Paul Lemert, Siemens North American SimaticIT partner manager, the product is built on core content with a number of added pieces leveraging Microsoft .Net technology. “The heart of the system is a graphical workflow editor that enables the programmer to link all the various modules with no coding. The editor is Web-based, using hypertext markup language (HTML) for the client. The programmer just draws the interactions of modules on the screen. The missing link in MES was the ability to work not just within its silo, but to work across silos. What we do is to add context to data. The more context you add, the more valuable it becomes.”
Jane Biddle, vice president at analyst firm AberdeenGroup Inc., in Boston, says, “New-generation manufacturing execution systems tend to have broader solution footprints, are easier to integrate and less expensive to maintain than previous-generation solutions.” Biddle notes that the MES manages work orders throughout production, combining materials, equipment specifications, labor requirements, and direct connections with distributed control systems (DCS), programmable logic controllers (PLCs) and laboratory information systems (LIMS) into each target production step. “The new generation MES leverages business process models, business rules, workflow technology, Web services, service oriented architectures (SOA), libraries of manufacturing component applications and industry standards to drive and interactively manage production,” she continues. “Real-time factory floor data is collected from various automation and test systems, aggregated and contextualized, and often displayed on dashboards relative to continuous improvement program metrics.”
Perhaps the context of business has changed as much as the technology leading to the growth of MES. Kevin Roach, Rockwell Automation vice president and general manager of Rockwell Software, in Milwaukee, suggests, “Take a look at the world of business right now. Companies have multiple businesses and control systems, as well as plant-wide information systems, production disciplines and performance visibility within each of the applications to integrate. They need to connect the factory to their ERP (enterprise resource planning) systems, and with so many plants and systems, establishing a single version of the truth is difficult. They really need an enterprise-wide view of operations.”
The Rockwell Software FactoryTalk product is built on the foundation of software services. In May, Rockwell is releasing the FactoryTalk Integrator. Built in cooperation with software giant IBM Corp., Armonk, N.Y., this product provides tools to enable real-time transformation, integration and workflow across disparate systems, as well as collection and storage of master data, event, process and production information. Powered by IBM WebSphere business integration server, Integrator will provide a transactional information framework to integrate Rockwell Automation products, and collaboration between other business and manufacturing systems using standards and common objects.
Hans Koning-Bastiaan, director, Corporate Automation Engineering CCP-2, at biotechnology company Genentech Inc., South San Francisco, Calif., agrees with the assessment that MES vendors have changed their product focus toward more modular, user-friendly applications. “It is true that in the past, the system was monolithic and the name MES was used for a system that replaces the paper ticket. The main advantage was that the information was collected in a relational database for further processing. The new technologies make it more modular and it is easier to connect the MES system and integrate with other systems. We are integrating the MES with our Honeywell distributed control system and with the Enterprise Service Bus (ESB). The new technologies make this possible. By the way, Honeywell is doing this integration for us.”
The Genentech plant is highly automated, and Koning-Bastiaan notes that an MES system would only make sense if it were fully integrated with the automated systems. “This means that the recipe runs in the MES system, which then in turn calls upon unit phases in the control system,” he adds. “This integration makes it possible to collect data that is generated by the automatic control system. The ESB integration gives a flexible interface to higher-level corporate systems such as ERP, LIMS, document management systems, and the like. We are an FDA (Food and Drug Administration)-regulated company, and are required to disposition the batch material based on pre-set recipe limits that are compared with actual processing data. The MES, together with an integrated DCS, is a great enabler to make a complex process simpler and more accurate.”
Koning-Bastiaan expects to achieve a single electronic truth of operations, resulting in better efficiency in production and in scheduling of material, equipment and resources. Other expected benefits from the system include reduction of cycle time, increased consistency in production and incremental process and product improvement.
Claus Abildgren, marketing manager for production management for Invensys/Wonderware, a Lake Forest, Calif., software vendor, states, “Enterprise integration is the hot topic. And, unlike five years ago, manufacturers require a much more flexible approach to MES. There is also more attention being paid to this area by top management. They realize that the products they are using fail to provide sufficient context or integration.”
There are two dimensions to this flexibility. One is flexibility to grow in overall system size. Abildgren says that customers want to start with a pilot project at a plant, then scale up to the enterprise. Even more important to customers, he says, is flexibility in system functionality. “They may have three plants that need different functions to start with. One may want traceability, another quality and so forth. But they really don’t want to buy a huge application with all the functionality, and force all plants to adapt. So they start with one function and build from there.”
There are many drivers in the business environment causing manufacturers to investigate the latest MES applications. Marc Leroux, collaborative production management marketing manager for automation supplier ABB, in Cleveland, has seen an influx of government regulations become one of the most important drivers. This has become most important for those in the pharmaceutical, chemical and food industries. Traceability has become the most critical function for these manufacturers, but other functions people are asking for include quality modules, production scheduling, alarm analysis and help in figuring out root cause analysis.
Can we trust it?
“The big problem of traditional MES,” states Leroux, “is not getting the information. The big problem is putting it into a context so that decisions can be made. MES today must also be able to take information from different systems and put it into a common data model without replicating it in different databases such that the data become untrustworthy.”
Traditional MES was known to be an industry specific application. Every part of the product was built to support the nuances of the particular targeted industry. This can be an expensive and limiting approach, given the rapid development of standards and integration technologies.
John Dyke, production management team leader at automation vendor GE Fanuc Automation, in Charlottesville, Va., add-resses the vertical nature of MES thus, “You have to understand vertical markets within a horizontal perspective. The vertical domain requires industry expertise. This would include such things as production management, manufacturing intelligence and execution down to the plant floor. However, analytics is almost completely horizontal.”
Adds John Leppiaho, GE Fanuc product manager for plant applications, “The key is what you are doing to make the application capable and scalable. We’ve learned that conformance to standards such as ISA-88 and ISA-95 increases the velocity of being able to deploy across multiple platforms in a business.”
Dyke continues, “Changing technologies are allowing better data exchange, but the cultural division between the shop and executive level is the problem. There is an evolution happening right now. A new group of people called ‘manufacturing IT’ are taking a leading role in this new integration.”
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