During the assembly process, operators can waste a lot of time searching and reaching for parts and tools. That's why engineers are giving workstations a lean makeover and helping operators become more productive:
What's the difference between an ordinary workstation and one that is lean? Two words: motion economy. A lean workstation is designed to minimize the unnecessary movement--including reaching, walking, twisting and turning--and wasted time that can occur during product assembly. "With a lean workstation, everything must be choreographed like an orchestra, so that every movement has a purpose," Rick Harris, president of South Carolina-based Harris Lean Systems Inc., says in a recent Assembly Magazine article. In a lean workstation, operators obtain parts and assembly tools as needed, on a just-in-time basis.
In designing lean workstations, manufacturing engineers try to enhance the operator's productivity as much as possible, tackling such key issues as safety and ergonomics. Engineers make sure that operators can pull parts efficiently and spot tools right away. In fact, they arrange materials so that assemblers can access them without even looking. In contrast, traditional workstations are haphazardly arranged, with parts and tools laid out horizontally across the work area. "A lean workstation has more vertical presentation, so tools and parts are closer to the operator," observes Eric Dotson, general manager of Georgia-based GWS Inc., to Assembly Magazine.
Additionally, lean workstations must be adaptable and flexible. They must be able to accommodate changing assembly processes. In other words, lean workstations should be easily reconfigurable. "In a lean environment, you must always keep flexibility in mind and be ready with A, B and C workstation variants to produce different [items] with minimal changeover times," says Art Smalley, president of California-based Art of Lean Inc., to Assembly.
In order to design truly lean workstations, engineers should not only observe operators firsthand but try performing tasks in the workstations themselves, experts recommend. This way, they can ascertain, say, the most comfortable positions and how much force is required. Additionally, according to Quarterman Lee, president of Missouri-based Strategos Inc., engineers should analyze specific areas such as materials handling; tool documentation and parts arrangement; and organization and storage. Also, they should learn the basic principles of ergonomics, says Ray Gottsleben, sales and marketing manager at Oregon-based Arlink Workstation Systems. They include the three main ergonomic operating zones: optimum work zone, optimum grab zone and maximum grab zone, he says. What's more, engineers must make sure that workstations accommodate "takt time"--a lean manufacturing term that is determined by customer demand of finished units.
In short, lean workstations take a lot of planning and analysis. But once they're up and running, they support lean assembly, boost productivity and make repetitive tasks easier and more effective for operators.
Lean Workstations: Organized for Productivity
Assembly Magazine, February 1, 2005