Lean manufacturing primarily means eliminating waste at every stage of production and streamlining a processes to offer greater value to customers.

This management philosophy has become increasingly well known as companies such as Toyota have used it to make astonishing competitive gains.

The globalization of markets has focused the need to optimize processes, and companies find they are compelled to improve their manufacturing methods.

To illustrate the potential benefits of lean manufacturing for welding operations, consider a plant that produces front-end loaders using 35 arc-welding specialists.

The shop used a systematic approach to measure welding process parameters and skills. Welding processes then were monitored to measure deviation from optimal parameters, which made it possible to diagnose specific areas in which lean management methods could deliver continuous improvement.

The five basic principles of lean manufacturing were applied to the plant's welding operations.

The first principle is achieving perfect first-time quality.

Attempts to achieve this objective focused on fillet welds.

Fillet welds often are ignored by engineers, who take for granted that welders are sufficiently skilled to make them correctly, yet fillet welds are the source of many fatigue failures.

The shop decided that producing perfect fillet welds, every time, would be its starting point for the lean process.

It began by measuring the in-process parameters among a sample of welders and discovered that 37 percent of the sample group did not make good-quality welds the first time. Kaizen events to improve fillet weld quality were initiated.

The second major principle of lean manufacturing is waste reduction through the elimination of all non-value added activities.

Excess weld metal, along with the resulting wasted effort during welding operations, offered another excellent opportunity for improvement.

In the case study, it was discovered that weld sizes exceeded the design requirement of ¼ in. by one-third to more than double.

Other adjustments also were required to minimize waste: Simple lap fillets were used instead of flare groove welds in the design of certain parts; to reduce the dimensions of fillet welds, filler metal wires were standardized to one size; and gas welding parameters were optimized. The shop used a variety of measuring devices and instruments to implement these measures efficiently.

Once optimal welding parameters were established, the third basic principle of lean manufacturing — continuous improvement — was started.

Every week, the Kaizen team recorded production welding parameters of wire feed speed, welding speed, quality of welding, and the extent of overwelding.

Throughout the plant, on-the-job training was provided to welders who were not performing to the new standard.

The results were impressive.

After eight months, the average welding speed increased by 6.4 in./min. (to 24 in./min. from 17.6 in./min.) - a 36 percent improvement.

In addition, the average cost per foot of perfect first-time fillet welds shrunk by $0.44, to $1.13 from $1.57.

That improvement represents potential annual savings of $526,772. The company saved $400,000 in the first year alone. By decreasing waste and increasing welding speed, the company thus achieved significant savings and throughput.

The last two major principles of lean manufacturing are flexibility in production and long-term relationships with suppliers.

It was observed that, despite marked improvement in welding productivity, bottlenecks were frequent at the final assembly of the machines, so the company turned its lean manufacturing teams loose on improving its electrical, mechanical, and hydraulic systems.

To initiate and continue the lean effort, the company's president secured a four- year contract with its supplier of welding consumables and gases.

The supplier had a team of welding engineering experts who provided its own value added service to the plant for Kaizen events on wire feed speeds and reducing undercuts, and on welding speeds and fillet weld sizes.

Plant inspectors learned to measure and report the parameters targeted by the events to ensure that the newly established productivity standards would be maintained over the four-year contractual period.

The principles of lean manufacturing resulted in continuous improvement to every aspect of the plant's welding operations. After 12 months, the plant increased productivity significantly and saw major savings.

Lean is a long term commitment and dedication to achieve the desired results, and the common denominator of such success stories in lean manufacturing is the commitment of upper management to the continuous improvement process, no initiative of this type has yielded equivalent results without the active participation of top management.

Equally vital to the project's success is effective communication with employees to ensure they understand what is being done and participate fully in the process. Many managers believe that the key to the success of their lean manufacturing project is the positive attitude of their employees.