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Manufacturing Execution Systems

Medical Device & Diagnostic Industry Magazine
MDDI Article Index

An MD&DI November 1997 Column


Bridging the gap between MRP/ERP systems and shop-floor controllers, an MES package can reduce manufacturing cycles, prevent production errors, and simplify the documentation process.

The term manufacturing execution system (MES) was coined in 1990 to describe a suite of software functions that reside between MRP/ERP (materials/enterprise resource planning) systems and manufacturing control systems. An MES makes it possible to pass information back and forth between an MRP/ERP system and programmable logic controllers (PLCs), distributed control systems, and supervisory control and data acquisition (SCADA) systems on the floor of a manufacturing facility.

An MES ties together many systems and functions, including plant maintenance, laboratory information management systems (LIMS), document control, documentation for training, standard operating procedures (SOPs) for running production machines, raw-material handling, and corporate information systems. From the MRP/ERP system, the MES receives information on customer orders, bills of materials, drawings, resource requirements, process plans, work instructions, assembly steps, manufacturing process plans, SOPs, raw materials, and inventory; it then translates this information into a manufacturing execution plan that reflects current conditions on the plant floor.

In executing the manufacturing plan, the MES exchanges information with inventory, QC, and document management systems and with shop-floor machine-control systems. Typical functions include work-order dispatch, work-order tracking, capacity scheduling, report generation, and statistical process control (SPC). The MES passes machine settings and parameters to the machine controllers and receives real-time feedback concerning job and process status.

On the shop floor, the MES sends electronic work instructions to guide the workers and equipment through the procedures while confirming that workers take the required steps. As explained by Harvey Cohen, senior vice president at Base Ten, Inc. (Trenton, NJ), and developer of the company's Pharmasyst system, "At a workstation, the operator sees the status of each batch of products. The MES tells the operator what to do­for example, this piece is waiting, this one is finished, this operation gets sampled. Thus, MES cuts down on the training needed and the loss of information."


The most compelling reasons for installing an MES concern manufacturing productivity, efficient data gathering, and simpler, more accurate management of documentation­all of which can lead to lower manufacturing and regulatory compliance costs.

Breakdown of the 1996 manufacturing execution system market by industry (Advanced Manufacturing Research, Boston).

A survey of users across all industries, conducted by the Pittsburgh-based Manufacturing Execution Systems Association International (MESA), found that an MES reduces manufacturing cycle time by 45%. On average, work-in-progress falls 17%, manufacturing lead times fall 32%, and product defects fall 15%. Data-entry time is also reduced 75% on average. Consilium, Inc. (Mountain View, CA), calculates that its FlowStream MES package is responsible for reducing document cycle times by 60% at one pharmaceutical plant and saves 64% of costs associated with documentation for GMP purposes. Base Ten claims a medical products company can cut the time a product takes from production to shipping by 10­20%.

Pacesetter, Inc. (Scottsdale, AZ), in manufacturing the electronic circuitry for its cardiac rhythm management products, installed an MES from Promis Systems (Nashua, NH) to automate recordkeeping. Previously, at each assembly step, an operator manually entered process information and initialed the paper to verify that each step was completed. This control procedure was time-consuming, cumbersome, and difficult to manage.

The Promis MES eliminated the paperwork while speeding data collection and improving data integrity; it reduced cycle times by one week, reducing work-in-progress inventory costs by $500,000 annually. Reduction in scrap saved another $25,000 annually. Labor costs fell by $200,000 yearly.

In improving productivity and quality, an MES identifies manufacturing problems and communicates the information to the necessary personnel in real time. Problems can be speedily resolved to minimize work disruptions. The QC department is instantly notified of a variance and can correct it without delay. Production is notified instantly when it can proceed. Information is shared in real time among interested parties to help resolve a defective product or process, again speeding production flow and throughput. Administrative load lightens, and the opportunity for documentation and GMP compliance errors is substantially reduced.


Many suppliers are seeking to increase their manufacturing agility, emphasizing more product introductions, smaller batches, special batches, and shorter lead times. MES is well suited for high-mix operations where the basic product varies, inventories are low, orders are frequent, and lot sizes are small and of different runs. MES also helps foster mass customization of products and allows manufacturing to respond to rapid product changes.

Bill Swanton of Advanced Manufacturing Research, a market research firm based in Boston, believes that MESs hold the greatest potential for manufacturing operations that produce new, short-run, high-volume products, rather than old production lines turning out well-established products. Cohen agrees, noting that for an older product, running on the same production line for years, it's probably better to leave the manual operation alone. "It works, does what it's supposed to do, employees are used to it. . . . It may be too expensive to change," he explains. That's why new, highly automated plants are the best candidates for MESs.

The step displayed on this screen guides the operator through lid assembly. Inspection and sign-off complete the process (INCODE Corp., Herndon, VA).


FDA's increased scrutiny of device manufacturers and demands for more stringent recordkeeping provide an additional incentive to install an MES. "Recordkeeping requirements have become more onerous and cost of compliance high," says Swanton. Citing FDA's Final Rule on Electronic Records and Electronic Signatures, Swanton notes that "The ruling has manufacturers who were sitting on the fence seriously looking at MES." Through its electronic signatures ability, an MES simplifies and reduces the cost of compliance. Moreover, electronic signatures and electronic recordkeeping help carry companies toward a paperless environment.

This manufacturing process menu guides the operator through each step of assembly.

Recordkeeping is also an important component of traceability, and here again an MES offers distinct advantages over current systems. Because it collects historical process data, an MES provides traceability to a batch of product or to components that go into the product. For example, if a hospital has a problem with a syringe, an MES can automatically trace the serial number, the original batch, and the components that went into it. The problem might be traced, for example, to a batch of rubber from a particular supplier. Without an MES, it might take days to find the information by sifting through paper records in several file cabinets.

With an MES, all information is collected electronically in one place instead of in paper files located in various company departments. Reports are easily produced electronically. An MES builds the batch record as it goes, tracking production status, results, costs, and how many units were made, passed, and failed. It assures each batch is made to SOPs and reveals actual utilization of equipment and resources by product line and batch.

Cohen gives an example: "When one of our customers, before installing Pharmasyst, used to decide which sampling of test plans applied to a particular batch of a product, they had to go through three or four layers of charts, graphs, and tables. That's all automated now."

Final auditing of a batch before shipping comes together electronically, rather than having people collecting pieces of paper. Because the system performs the auditing checks as it goes along, little checking remains after everything has been signed off electronically.


Software is evolving to make MES even more attractive. As Cohen explains, "Until recently, software and database technology and the hardware network weren't robust enough to support this kind of multiple-system integration." Architecture is moving toward object-oriented C++ programming, which makes possible more flexibility, greater modularity, and better integration with other systems.

Software systems are also growing more standardized, thanks in part to organizations such as MESA, who are trying to define what an MES should do. "In previous attempts at MES," Cohen says, "software developers tried to connect with other systems with limited success. Five or six years ago, you faced a choice between a dozen database vendors, network vendors, and a similar choice of languages. Standardization was absent. It was chaos­a nightmare of failures."

During those years, medical product companies sometimes tried to form their own MES-type systems, but they were generally hard to maintain, connect, validate, and operate properly. Similarly, the QC department might create its own QC system, or research would create its own LIMS. All would keep separate records. The situation gave rise to unconnected "islands of automation." For example, the company might have an inventory system for the warehouse but not connected to the batch production system. "Systems couldn't talk to each other. There was a lot of paper shuffling instead," says Cohen.

Standardization has improved the software situation in the past few years. Windows NT, Microsoft Sequel Server, Novell, and Oracle have emerged as the big players, and the Microsoft platform has emerged as the MES standard.


MES functionality also continues to improve, driven by ventures such as the NIST-sponsored SMART project (National Industrial Information Infrastructure Protocols/Solutions for MES Adaptable Replicate Technology), a three-year, $13.5 million effort to develop adaptable MES interfaces based on intelligent agent technology. The SMART project will work on experimental, highly flexible technologies to simplify the task of integrating and sharing real-time data across the different planning, tracking, and control systems employed by the nation's manufacturing industries.

Bob Lechich, FlowStream product marketing manager for Consilium, expects MES to carry over into the sales-order management systems that salespeople carry in the field. "When a hospital orders scalpels, the representative, through his sales-order management system talking to the MES system, can nail down a delivery date. The salesperson talks to manufacturing right there from the hospital purchasing office. The firm delivery date helps the hospital contain costs by reducing inventory. The device company, similarly, reduces inventory by ordering material only when the customer wants it."


Installing an MES takes a cooperative, interdisciplinary effort by all departments. It's not just manufacturing's purchase but affects information technology and quality assurance as well.

Vendors also warn that the purchase price of an MES­$500,000 and up­is but one part of its total cost. Company departments might have to change processes and install networks. Procedures need to be reviewed and streamlined, and documentation needs to be converted into electronic form. Machine controllers often need to be upgraded so a PC can talk to them. The cost of redoing procedures can comprise 25­50% of the total MES installation cost.

Then there's the cost of validation. Swanton says validation amounts to 40% of the installation cost. To help ease the validation process (the tests, protocols, reviews with vendors for software good practices), MES vendors guide medical device companies through it. For example, INCODE Corp. (Herndon, VA) provides documentation and test plans for internal and output qualification, claiming it can cut validation time from 18 to 6 months. Base Ten implements Pharmasyst using GMP-type procedures, which makes it easier for the customer to validate.


In 1996, the medical product industry represented 13% of the MES market, and this percentage is expected to rise. According to MESA International, 13 vendors offer MESs to medical product companies, but the three main suppliers ­INCODE, Consilium, and Base Ten­clearly dominate. Cohen doesn't expect this situation to continue, however. Man-machine interface (MMI) and SCADA suppliers could add MES functionality in the future, and ERP vendors are trying to move into medical product MESs or form alliances with MES vendors. INCODE, for example, has developed an interface to SAP, the largest ERP vendor, using EnvisionIt's VisualFlow software, an application integration tool designed for the manufacturing industry.

As more medical product companies realize the value of an MES, more will jump on the bandwagon. "Over the years, we'll see MES activity pick up," predicts Swanton. Cohen agrees, adding that MES is becoming "the price of admission to being a worldwide supplier. It proves your system conforms to international standards such as ISO 9000." As a tool for continuous improvement, its vendors claim an MES can transform an enterprise into a world-class manufacturing organization.

Robert S. Seeley is an industrial and medical writer based in Bridgewater, NJ.


Baxter Healthcare Corp.'s IV Systems Division is installing MESs at seven plants worldwide. By reducing documentation and the work associated with it, Baxter hopes that the systems will help to shorten lead times, speed product turnaround, reduce errors, improve quality, and cut costs.

Part of Baxter's rationale for installing the Process Operations Management Systems (POMS) from INCODE Corp. (Industrial Computing Designs Corp., Herndon, VA) was to standardize information management systems between plants. Mike Easley, coordinator for Baxter's MES implementation plan, expects that the shop-floor MESs will eliminate the problems that arise when different plants operate different software systems, launch independent automation efforts, and choose different vendors.

The MESs operate by transferring production data into Baxter's standardized MRP system, which includes accounts payable, inventory, and raw materials scheduling. Baxter also plans to integrate the MESs with corporate distribution, order processing, and other systems, including the laboratory information management systems at each plant.

At a manufacturing plant in Cartago, Costa Rica, an operator with Baxter Healthcare's IV Systems Division enters data into a cart-mounted PC, which feeds data into INCODE's POMS.

The first POMS modules installed were the materials management modules, which automatically handle receipt of materials, bar code labeling, and control testing and inspection of incoming materials. Each MES directs and tracks the movement of material in the warehouses and updates inventory status. The materials management module also sets controls that prevent operators from making mistakes or performing operations out of order. The system relieves the operator from the task of recording data manually; instead, the operator enters data electronically, or the system "automatically grabs the data and puts it where it needs to be," as Easley explains. The MES then generates reports, in real time, which managers can analyze to ascertain trends and other information. Better data enable managers to make better decisions for operational improvements and facilitate the tracking of batches and materials.

Other POMS modules currently in pilot phase or validation testing include modules for device assembly/packing, sterilizer truck tracking, and weighing/mixing. The weighing/mixing module, for example, automatically generates electronic mix records and controls dispensing and data collection at the mixing tanks.

Baxter's manufacturing plant in Cartago, Costa Rica, was the first to install the device assembly/packing module. Under the new system, an operator wheels a cart mounted with a wireless laptop PC to the workstations in the cleanroom and enters data related to product release. Some of the data, fed into the assembly/packing module, indicate that machine parameters are set and ensure that they stay properly set; other data verify that products meet required parameters. If the system detects problems, it handles the exceptions and generates exception reports. The assembly/packing module interfaces with the materials management module, which verifies raw materials before use.

The Cartago plant system is connected by a wireless local area network (LAN) bridged to a token ring. A wide area network connects all the plants in Baxter's IV Systems Division. Baxter reports that in the Cartago plant, the assembly/packing module has slashed the number of documentation-related activities by 65% and similarly reduced documentation errors. The product release cycle has also been significantly reduced.

Copyright ©1997 Medical Device & Diagnostic Industry
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