Six Sigma under TBEM

12 August 2002

Developed by Motorola in 1986, Six Sigma employs a range of strategies and tools to eliminate defects in processes. Sigma, a letter in the Greek alphabet, is used by statisticians to denote the standard deviation of a process. To achieve Six Sigma quality, a process must produce no more than 3.4 defects per million opportunities (an opportunity is defined as a chance for non-conformance, or not meeting the required specifications). The higher the number of defects, the lower is your Sigma score.

There were many Sigma defects that Tata Engineering had to eliminate to get back on track. The weight of competition, ever-increasing customer expectations and shifting market conditions made change an absolute imperative. The company’s older vehicles were getting obsolescent, and its newer ones were lagging behind in terms of customer satisfaction.

Winning strategy
"We realised that to succeed we had to completely reorient the company’s thinking and the thinking of our people," says
Atam P. Arya, Tata Engineering’s senior vice president overseeing the quality initiative. "We had to stop treating quality as a burden and start accepting it as the main purpose of our existence. Quality became, for us, the strategy for survival — and for winning."

An important challenge for Tata Engineering was in changing the mindset of its people. "Initially our people were very sceptical; they thought this was some new fad that would soon go away." To ensure it did not, the company conducted a blanket communication and training exercise across the organisation. This started at the highest levels, with the leaders and managers, and then percolated to the rest of the employees.

The focus of the Six Sigma programme at Tata Engineering was, and remains, the customer. The company took its products and analysed what customers would want from them, and the critical-to-quality (CTQ) characteristics they would be looking for. For instance, a customer buying a truck will consider whether it measures up in terms of load, speed, fuel efficiency, operational smoothness, etc. These are his CTQ characteristics.

As long as a CTQ attribute can be defined, it can be incorporated in the Six Sigma model. These attributes can then be linked to the manufacturing parameters that must be achieved under the Six Sigma process to meet a customer’s expectations. Tata Engineering drew up a whole system around this, the stated goal of which was: "To achieve a major breakthrough and a sustainable quality improvement in all our products and business processes."