Going back to the boy-scouts walking in a line analogy, the whole troop can only arrive at the campsite when the slowest boy arrives. The slowpoke – the bottleneck – determines the throughput.
This insight leads to an interesting conclusion.
Once Alex identifies the bottleneck process in his plant, he realizes the true cost of operating (or not operating) the bottleneck machine. Whenever that bottleneck machine is not operating, the entire plant is not producing throughput. 1 hour of downtown on the bottleneck represents the ENTIRE PLANT being down for an hour.
This leads to some interesting math. Rather than compute the cost of running that machine like he normally would – some combination of salaries, overhead, etc. – the true cost is more accurately measured by the revenue lost from not making 1 hour’s worth of product.
If you buy this, then you realize the simple fact that the bottleneck limits all revenue. As a result, you should do whatever you need to do to improve bottleneck throughput.
Here are some things Alex does for the bottleneck process in his plant:
- Eliminate lunch breaks for people on the machine, unless the machine is loaded and running
- Add people to ensure machine set-up and batch-changes are as fast as possible
- Identify any part destined for the bottleneck as high priority and make sure it gets to the bottleneck
- Keep a queue in front of the bottleneck as padding in case machines that feed the bottleneck break down or experience slowed output
- Hire a motivational coach for the machine to keep it focused and motivated
Most of those things actually happened in the book, but I added the last one as a joke. It’s truly, undeniably hilarious – perhaps the pinnacle of humor for mankind.
Bottlenecks are important. They limit throughput.
If you have a slow-poke in your boy-scout troop, lighten his load and help him move faster. If you have a bottleneck in your plant, do what you can to increase its throughput.