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by Charles Rastle and Julie Fraser

Using Six Sigma initiatives to focus on improving the performance of business and manufacturing processes isn’t a new concept. But a growing number of manufacturers seeking to stay competitive and improve profitability are, instead, turning to Six Sigma to provide stronger value to customers. As a structured and fact-based means of achieving continuous improvement, Six Sigma programs need accurate data to analyze current performance issues and their root causes. Measuring improvement--in terms of defects per million, for example--requires accurate data.

Unfortunately, some Six Sigma programs get bogged down in the area of data collection, particularly when collecting information related to production, fulfillment and service operations. Sometimes, Six Sigma teams--whether comprising trained Black Belts, Green Belts or other employees--spend significant time manually gathering data that they aren’t confident is correct, which can cause justifiable frustration. If the gathered data has built-in bias at the source or is subject to interpretation, the results of analysis will be suspect. At the very least, progress will be slow, which can blunt support and momentum. Furthermore, manual data collection is inherently error-prone, so an analysis may be skewed by the Six Sigma team itself.

Preventing Six Sigma programs from withering due to a lack of rich and accurate data requires sound information systems. Ideally, these information systems should gather data automatically at the source of an activity, which would avoid data-source inaccuracies as well as errors potentially resulting from human interpretation or filtering.

Six Sigma teams can benefit even more from data available in a form that already correlates processes to products and customer orders. In a production plant setting, a manufacturing execution system is designed to provide just such data. As an MES guides the execution of production processes, it can also gather detailed data about the process, materials and production. The information can be correlated to show all materials that go into a product--and the conditions during all of the process steps the materials underwent. Many of these systems are tamper-proof to help companies meet regulatory requirements, so there’s little room to question the data. An MES is a rich source of detailed yet contextualized information that allows Six Sigma programs to take root and flourish.

Improving Six Sigma results

Research findings from a newly released report, “MES Performance Advantage: Best of the Best Plants Use MES,” illustrate the benefits of MESs to plants undertaking Six Sigma programs. Written by Industry Directions and sponsored by Rockwell Automation, the report uses an existing database of survey responses to questions about performance and business practices and compares companies that are and are not using an MES.

In a database of 106 plants judged to be the highest-performing in North America during a period of five years, 24 responded that they use Six Sigma methods extensively. Within that group, 58 percent of respondents with Six Sigma initiatives also use an MES. Despite the relatively small number of Six Sigma users, the differences within the group are striking. (All percentages listed here are the mean response of the group mentioned--those using Six Sigma and either using or not using an MES.) Here are some results:

Companies using an MES together with Six Sigma improved their profitability 151 percent over three years, whereas those using Six Sigma without an MES improved profitability by 22 percent, as illustrated on this page. Improving profitability by even 20 percent is impressive, but organizations with an MES improved 678 percent more, on average. Some of this profitability came from improved productivity for plants using an MES and some came from cost savings.

Process capability is a cornerstone of Six Sigma strategy. The goal is to create business processes that generate 3.4 defects per million or fewer (Six Sigma including a 1.5 sigma drift). Again, the MES fostered much greater success for the group of companies undertaking Six Sigma in this study. Companies using an MES together with Six Sigma had a process capability (Cpk) of 2.4, compared to 1.5 for those not using an MES to support their Six Sigma initiatives.

Some specific process results were greater cycle-time reductions over three years--more than 54 percent greater in order-to-ship cycle time, the primary target for customer satisfaction. And, among plants using an MES with Six Sigma, the manufacturing cycle time component shrank by more than 82 percent compared to plants using Six Sigma alone (60.6% vs. 33.2% over three years). In a previous study by Industry Directions, “Becoming Demand Driven,” the key indicator of demand-driven performance was revealed to be achieving cycle times shorter than the customer order lead time.

Companies using an MES with Six Sigma also decreased lot sizes more dramatically and were better able to build to order. For just-in-time orders, the plants using an MES built entirely to order 85 percent of the time; those using Six Sigma without the MES data source built-to-order for JIT 40 percent of the time, as illustrated in the chart. Customers who ordered on a JIT basis and got exactly what they wanted built for each specific order were likely to be more satisfied.

The study reports other benefits of MESs, both to companies with Six Sigma programs and overall. What is clear from this data subset is that having accurate, reliable and comprehensive operational data from an MES helps companies fully leverage Six Sigma initiatives. Those using MESs realize significantly more dramatic gains in performance.

MES and DMAIC

The five critical processes used in a Six Sigma program are define, measure, analyze, improve and control. An MES provides a foundation of data and ongoing support for all of those except define--which it assists.

Define--Identifies business issues that affect the customer, defines project goals and boundaries, and distinguishes issues that must be addressed for improvement. Here, existing MESs can be used to help identify problems that must be addressed, whether in the process, materials or output.

Measure--Gathers information about the current situation as baseline process performance data and identifies problem areas. MESs provide data about plantwide process performance, usually with both current and historical data available.

Analyze--Identifies root causes of problems and confirms those causes with data-analysis tools. Again, an MES has the foundational data, including all production processes correlated to each other and the materials that flowed through the manufacturing process, the personnel that worked on them, the conditions in the plant and the customer order that was filled. An MES can also feed its data into analytical tools, and some MESs now have internal operational analysis capabilities in the off-the-shelf software product or can be built-in during integration.

Improve--Implements solutions or changes to the business processes to address the root causes identified during analysis. The MES can be reconfigured to change process parameters or flows, indicate conditions outside control limits and provide operators with the necessary data to avoid or correct problems early.

Control--Ensures day-to-day business processes stay in the improved state and become standard and integrated into the daily routine. The MES can enforce business processes--disallowing operations when certain conditions are not met, for example. It also measures performance on an ongoing basis to evaluate the success of an improvement.

The new face of MESs

The July 2003 issue of Quality Digest featured an article, “Six Sigma for the Rest of Us,” which discussed ways smaller companies can succeed using Six Sigma without making major investments in Black Belt training or major process redesign. In keeping with this philosophy, MES technology is becoming more available to companies of all sizes. A variety of MES solutions are available today to meet the unique requirements of companies large and small. Both MES and Six Sigma solutions can be focused on a specific piece of equipment or plant area, or they can provide a comprehensive solution that manages the operation of an entire production plant.

MES applications utilized in itemized situations are modular solutions designed to collect and provide visibility into equipment operating data. An MES solution provides information needed by Six Sigma Black Belts to measure current performance, analyze operations and identify opportunities for improvement. MES applications can also provide feedback to operators, enabling them to ensure that equipment or a line is operated within defined control conditions.

The advantage of such modular solutions is that they’re focused on requirements of a specific production area or process. They’re configurable and have been designed to meet the requirements of a specific area of the manufacturing plant. The plant does not need to change its operations to fit the MES. Rather, the MES can be configured to meet the needs of the plant.

MES applications now being deployed are also scaleable. In many cases, a Six Sigma project will be focused on a single piece of equipment or line. At the completion of the project, if value is demonstrated, the manufacturing company will want to deploy the MES throughout its operating plant. The current generation of MES applications has the capability to be rapidly scaled-up from a single line to an entire plant.

Many companies are deploying MES applications that enable the collection and analysis of multiple types of data. Data on machine downtime are no longer the sole information needed to improve the throughput of a production line. New MES applications allow Six Sigma teams to look at more complex relationships and analyze downtime data, quality data, operating conditions, product type and labor resources. In the past, this required Six Sigma teams to generate separate reports and then compare data across reports. Current MES applications allow Six Sigma teams to view data in a single application for review and analysis. This has been facilitated by the capability of MESs to exchange data among various enterprise systems (e.g., enterprise resource planning, material requirements planning and laboratory information management system) and their improved analytical capabilities.

An MES feeds healthy Six Sigma

In their book, Six Sigma: The Breakthrough Management Strategy Revolutionizing the World’s Top Corporations (Currency, 1998), Mikel Harry and Richard Schroeder discuss the fact that companies improving 1 sigma each year, from 3 sigma to 4.8 sigma, will experience a 20 percent margin improvement. Recent research shows that adding an MES to support the Six Sigma program can further boost margin improvement. At 151 percent over three years, the companies in Rockwell’s newest study average about 50 percent margin improvement each year. The reason for this success is twofold. First, the Six Sigma process is enhanced when its analysis can be based on critical production data present in an MES. This data enables Six Sigma teams to make their analysis and develop production improvement recommendations based on solid and consistent data. Second, an MES also provides data necessary to define current operations and establish a baseline to measure improvement and value delivered to the company.

A vehicle for change

Manufactures need to keep in mind that analysis of the existing situation and recommendations for improvement are just part of the Six Sigma process. MESs help provide the capability to monitor the production process and implement business process control to improve production execution.

Many Six Sigma projects and MES implementations have failed in the past because MESs have not been utilized to help drive the continuous improvement process. Manufacturers must view MES technology as a vehicle for business change and improvement in the manufacturing process.

By properly incorporating an MES with Six Sigma initiatives, manufacturers can effectively boost profitability, productivity and process across their operations.

About the authors

Charles Rastle is an industry strategic marketing manager for Rockwell Automation’s Global Manufacturing Solutions group. Rastle earned his bachelor’s and master’s degrees from the Colorado School of Mines, and he earned his MBA from the University of Colorado.

Julie Fraser is a principal and analyst with Industry Directions, a manufacturing and supply-chain analysis and consulting firm.