Saturday, February 17th, 2018
The fourth principle of the Toyota Way is:
Level out the workload. (Work like the tortoise, not the hare.)
Like with the fable about the tortoise and the hare, “slow and steady wins the race.” Maintaining optimal effort from operators is important, whether demand goes up or down. You don’t want to slow the process effort down when demand falls, nor do you want to double the individual efforts applied by operators when demand doubles.
Customers are not predictable and actual orders can vary significantly from week to week and month to month. If you build product as it is ordered, you may be building huge quantities one week, paying overtime, and stressing your people and equipment, but then, if orders are light the next week, your people will have little to do and your equipment will be underutilized.
You will also not know how much to order from your suppliers, so you will have to stockpile the maximum possible amount of each item the customers might possibly order. It is impossible to run a lean operation in this way. A strict build-to-order model creates piles of inventory, hidden problems, and ultimately poorer quality and in the end lead times are likely to grow as the factory is disorganized and chaotic.
Accumulate orders and level the schedule and you may be able to reduce production lead times, cut your parts inventories, and quote much shorter standard lead times to all your customers, resulting in greater overall customer satisfaction than a “hurry up, then slow down” build-to-order approach to production.
The slower but consistent tortoise causes less waste and is much more desirable than the speedy hare that races ahead and then stops occasionally to doze. The Toyota Production System can be realized only when all the workers become tortoises.
Summing-up: Toyota has found it can create the leanest operation and ultimately give customers better service and better quality by leveling out the production schedule and not always building to order.