Traditionally, a manufacturing execution system (MES) is defined as a production scheduling and tracking system, which schedules and updates orders, analyzes and reports resource availability, collects execution data—such as material and labor usage, process parameters, and order and equipment status—and maintains statistical quality control. But such a static definition doesn't do this genre of software justice because MESs are a work in progress.
In a recent conversation, John Leppiaho, senior product manager of Proficy software for GE Fanuc Automation, observed, "In the past ten years, MES has evolved into many different kinds of things. If you were to look back six or seven years ago at the MES market, you would see a different landscape than you would today. MES was something different in the past than what it is evolving into today." This change is occurring in three areas: functionality, scalability, and technology.
In many ways, MES's functionality has been shaped by enterprise resource planning (ERP) software. In the past, the functionality of the two overlapped, blurring the distinction between them.
Today, MESs are taking on roles that enhance and complement ERP systems. "Older MESs were fixed-footprint solutions that stepped on ERP systems," explains Tom Comstock, senior vice president of marketing and management for Apriso Corp. "The traditional definition had MESs doing everything to run a manufacturing plant. If you looked at mill-oriented MES products, they included things like sales orders processing. That's now typically done in the ERP system. Newer systems are ERP complementary. They fill the white spaces around the ERP systems. If you are looking to deploy them, you should be looking for an MES that complements and extends your ERP system rather than overlapping it."
Today, MESs feed manufacturing data to enterprise systems (e.g., alerts of production interruptions that will delay deliveries). At the same time, they take data, such as information on orders, from enterprise systems and make them available to the shop floor so that factory managers can run their operations based on the enterprise's needs.
Control and Improvement
In addition to collecting data to support the ERP system, the MES provides a mechanism for process control and improvement.
To implement control, the MES reads analog or discrete process data provided by sensors, PLCs, and RFID readers and identifies key control events, as defined by its business rules. It checks process-data values against the product specification for the order. If the values are within tolerance, the system will pack the order; if they aren't, it will put the order on hold.
The MES also provides an engine to model the production environment. Some MES packages allow factory managers to change processes quickly and implement improvements. A number of newer systems include applications that enable nontechnical users to build the procedures and processes to be implemented on the factory floor.
"MES isn't just an order execution system; it's about improving the process," says Leppiaho. "We are about empowering and changing the way people do business."
Beyond the Factory's Four Walls
Although MESs are still generally focused on activity within a single manufacturing facility, globalization is driving providers to extend the reach of their software. Increasingly, they are providing tools to coordinate manufacturing activities across multiple facilities and beyond national boundaries.
New technologies are being incorporated into the software packages to integrate and coordinate the efforts of suppliers and multiple manufacturing operations. Despite the growing scale of their operations, manufacturers still need the traceability and control that they found necessary in single-plant environments.
To accommodate the expanded manufacturing operations, MESs are turning to new technologies that streamline operational integration. Today's software uses service-oriented architectures (SOAs) and Web s ervices to provide a way to look at multiple processes, operations, plants, and suppliers.
"The industry is going through a generational change from the client-server architecture to the service-oriented architecture," says Comstock. "Some companies have moved to these new architectures, but many systems still rely on the client-server model."
Tom Kevan is a freelance writer/editor specializing in information technology and communications.
For more information:
Apriso Corp., Long Beach, CA; www.apriso.com
Gerry Ansel, 562-951-9068
GE Fanuc, Charlottesville, VA; www.gefanuc.com
Elli Holman, 508-698-7456
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