" In general, when you try to apply TPS, the first thing you have to do is to even out or level the production. And that is the responsibility primarily of production control or production management people. Leveling the production schedule may require some front-loading of shipments or postponing the shipments and you may have to ask some customers to wait for a short period of time. Once the production level is more or less the same or constant for a month, you will be able to apply pull systems and balance the assembly line. But if production levels the output varies from day to day, there is no sense in trying to apply other systems, because you simply cannot establish standardized work under such circumstance."( Fujio Cho, President, Toyota Motor Corporation )
Focusing on MUDA is the most common approach to implement lean tools, because it is easy to identify and eliminate waste. But what many companies fail to do is the more difficult process of stabilizing the system and creating "Evenness" a true balanced lean flow of work. This is the Toyota concept of Heijunka, Leveling out the work schedule. Achieving hejunka is fundamental to eliminate MURA, which is fundamental to eliminateing MURI and MUDA.
Heijunka is the leveling of production by both volume and product mix.
There are four benefits of Heijunka :
- Flexibility to make what the customer wants when they want it.
- Reduced risk of unsold goods.
- Balanced use of labor and machines.
- Smoothed demand on upstream processes and the plant's supplier.
Heijunka in service operations :
- Fit customer demand into a leveled schedule.
- Establish standard times for delivering different types of service.
Basic Thoughts
- Eliminating waste is just one-third pf the equation for making lean succesful. Eliminating overburden to people and equipment and eliminating uneveness in production schedule are just as important yet generally not understood at companies attempting to implement lean principles.
- Work to level out the workload of all manufacturing and service processes as an alternative to the stop/start approach of working on projects in batches thatis typical at most companies.
