Are the functions of a manager truly different in a lean manufacturing environment when compared with a traditional management structure? Of course they are. It is all a matter of the degree to which each incorporates production variables of their specific models that they will differ in some ways, and don’t differ very much at all in other ways. It’s important, though, to understand these differences for seeing what model—lean or traditional—works best in your own shop for managing people and processes.
So what are the differences? In a lean manufacturing environment production is based on real customer demand. In a traditional manufacturing environment production is based on what you hope to sell. Instead of pushing product into the market (a sometimes dangerous thing to do in this economy), lean production pulls the product through a system that is set up to quickly respond to a customer’s needs and demands.
While in a lean management approach to manufacturing, production is made to order and pulled from the existing order levels, in traditional management other forces are at work to counter the irrational tendencies inherent in the system. For example, in the lean approach, production is made to order; in traditional management, production is primarily based on forecasting and products are made to replenish inventories.
As well, cycle times for inventories themselves are measures in terms of hours and days in the lean approach, while cycle time are measured in terms of weeks and even months in the traditional model. In a related concept, lean management usually employs the one-piece flow inventory levels; by contrast, traditional methods continue to use the large batch production approach inherent in the push-production approach.
Costing is such an important issue in manufacturing today, that one would be hard-pressed to understand how or why quality would be a random consideration. Wasted time and material translates into wasted money and wasted profit. However, when mass production must use traditional management methods, quality assessment is indeed just that—random sampling. By contrast, lean management takes quality control to the station level in attempt to head-off inefficiencies and scrapping. In this way, the causes and corrective actions to change inefficiencies are assessed more frequently and with continuous improvement effect.
Certainly, scheduling is a much more important and flexible notion in the lean management approach to manufacturing. Changes in schedule—whether for order influx, machine maintenance, or any number of issues—is much more facilitated and capacity better planned. In traditional, large batch, production, however, schedules are usually much more rigid and harder to adjust merely because of the sheer volume of items on the production line at any single time.