Heijunka in Service Operations
Leveling out a work schedule is easier in high-volume manufacturing than in typically lower-volume service environments. How do you level schedules in a service operation where service providers are responding to customers and the lead times on service work vary widely case by case? The solutions are similar to the solutions in manufacturing:
- Fit customer demand into a leveled schedule. This is more common in service operations than you may think. Why is it that doctors and dentists schedule procedures and you need to fit into their schedule? So they can level the workload and have a constant stream of income. Time is money in service operations.
- Establish standard times for delivering different types of service. Again, the medical field is instructive. Even though everyone has somewhat different medical needs, doctors and dentists have been able to establish standard times for different types of procedures. And they separate diagnosis from the procedure. You visit, they diagnose you, and then, in most cases, they can predict the time that will be required for your procedure.
Toyota has effectively been able to level the schedule for product development even though lead times are months or even years. In most cases, Toyota will make minor updates to a vehicle every two years, adding features and changing styling, and will do a redesign of the vehicle every four or five years. Toyota product development works according to a matrix, where the rows are the different Toyota vehicles—Camry, Sienna, Tundra—and the columns are years. They decide when each vehicle will be freshened and go through a major redesign. They intentionally level the schedule so a fixed percent of the vehicles are being redesigned in any one year.
Planning when vehicles are scheduled for redesign would be futile if the lead times required to actually design and develop a vehicle were unpredictable. This is where Toyota has a big edge over some of its competitors. While some auto companies let the start of production slip by months or even a year, Toyota is like clockwork. Development milestones are met with virtually 100% accuracy. So the leveled plan becomes reality.
Toyota also has found there is a cadence to the workload requirements over the life of the development project: the workload is relatively light early in the conceptual stage, then builds up as they get to detailed design, and then reduces again in launch. By offsetting different vehicle projects, they know when one is peaking and others are in the light period and can assign the numbers of engineers to products accordingly. They also can flex the number of people needed by borrowing engineers from affiliated companies (suppliers and other divisions of Toyota, such as Toyota Auto Body). Affiliates can come onto projects as needed and then go back to their home companies, allowing an extremely flexible system and requiring minimal full-time employees. This is the result of other Toyota Way principles, particularly standardization. Toyota has standardized its product development system and the product designs themselves to the point that engineers can seamlessly come in and out of design projects, because their engineers have a standardized skill set similar to the Toyota engineers’ and years of experience working in Toyota’s system. The principle of long-term partnering that we will discuss in Respect Your Extended Network of Partners and Suppliers by Challenging Them and Helping Them Improve allows Toyota to have a trustworthy and capable set of partners who they can depend on for extra help when needed.
In short, it is possible to level the schedule in service operations. But there are some base requirements. You must follow all of the other Toyota Way process principles—flow, pull, standardization, and even visual management—to get control over lead times. Standardization is critical to controlling lead times and also to bringing people on and off the projects to address peak workloads. You must also develop stable partnerships with outside companies that are capable and that you can trust.