To drive sustainable quality improvement, lean embraces Six Sigma

The tie between lean and Six Sigma is found in lean tenets such as error proofing. But manufacturers readily mix the two approaches, and see them as complementary.

Jeff Woods, a Six Sigma master black belt and manager of materials at GE Consumer & Industrial's Appliance Park manufacturing facility in Louisville, Ky, says, "We've practiced Six Sigma for many years, and, in the last few years, have begun using lean techniques such as value stream mapping."

The plant—which makes appliances—also mixes production methodologies, some areas being batch-oriented, and others single-piece flow. A manufacturing execution system (MES) from GE Fanuc Automation tracks work-in-process, as-built data, and quality analyses.

Six Sigma is a problem-solving approach that uses statistical tools and rigorous training. While it can be applied to almost any business concern on plant floors, it's often aimed at eliminating process variations. Woods says Six Sigma complements lean tenants, such as standardized work and error proofing. The MES, he adds, gives Six Sigma experts ways of pinpointing areas for improvement. "Before, we spent a lot of time collecting information," says Woods. "Now, we can leverage the information in MES and jump right into the improvement stage. It allows us to increase the number of projects we take on."

Kevin Roach, a VP with GE Fanuc Automation, says MES, plant historians, and plant analytics accelerate Six Sigma "define, measure, analyze, improve, and control," or DMAIC. The software, says Roach, monitors minute variations that are hard to catch via reports or visual observation.

"Our applications spot micro-downtime events that drain efficiency," says Roach. "It's easy to spot if the machine or line goes down for hours, but it's those seconds of downtime that accumulate and bring inefficiency."

A wide range of vendors have entered the plant intelligence market, including big automation vendors that also offer MES, such as Siemens Energy & Automation. While Web-based access to plant metrics and MES are important to Six Sigma, MES also should be workflow-capable, says Khris Kammer, MES product manager for Siemens.

Kammer says Siemens' SIMATIC IT suite offers a "framework"-modeling environment that supports business process management and workflow so that plant-level events are communicated to the right people and higher-level systems. Says Kammer, "Our MES solution is focused on operations and workflow management, rather than just the data collection and data management of traditional MESs. The workflow enforces consistency in your processes."