Identifying Waste in a Value Stream Map
Gather strategic information for future improvements and for measuring performance
When analyzing value streams, you’re trying to root out inefficiencies — in other words, you’re figuring out what doesn’t add value, or is wasteful.
Identify sources of waste
When analyzing future-state value stream maps, you need to ensure all waste is removed because these maps are meant to provide strategic direction for future improvements and for measuring performance. If anything is wasted, these predictions may be off.
So when developing a future-state value stream map, you first identify sources of waste highlighted in the current-state map. Then you identify process blocks — areas where bottlenecks are occurring — and try to balance the production line.
Once you’ve identified waste, use the 5 Whys process — asking five “why” questions — to help determine its root cause.
For instance, say an operator spends ten minutes gathering required components, you could ask them why it took so long. Perhaps they explain that the stock is kept in a separate room in five different boxes. So you ask why it’s in so many boxes. And so on until you get to the source of the problem.
Consider the types of waste you encounter.
Why excess motion?
Excess motion, for one, is unnecessary movement and time spent walking around. For example, in a home theater system assembly line, workers may make several trips to collect components. A way to combat this motion waste is to put the components closer to the workers and giving them a trolley to collect a bunch at once.
Another type of waste to root out is overproduction, which occurs if more components or products are created than are needed. For example, a worker at a bicycle manufacturer welds three bicycle handlebars a minute.
The next worker in the line sands the welds and drills holes for assembly. This second worker can’t keep up with the pace and the number of handlebars awaiting processing gets larger and larger. Adding a third worker at the second station could solve this problem.
Why excess inventory?
Excess inventory is wasteful too, because it means materials, components, or products are stored unnecessarily. A pile of components or a bin of bolts at a particular point in an assembly line is an example of excess inventory. The components take up space.
To reduce inventory, you can implement single-piece production. You could also consider using pull systems that call for the number of parts needed as they’re needed, or kanban systems that signal when inventory needs to be replenished.
Why unnecessary processes?
When unnecessary processes are performed on a component or product, this is overprocessing waste. For example, adding three layers of paint when two is sufficient. To fix overprocessing, you simply remove the unnecessary processing steps.
By now you should have a good idea of the types of waste to look out for when analyzing a value stream. Only once you’ve discovered where the waste is in the system, can you work on reducing or removing it.