Understanding and Identifying Bottlenecks

When most production managers think about bottlenecks, they probably envision a piece of equipment, integral to the process, that runs slower or has more breakdowns and need for maintenance. That’s a fair reaction to envisioning bottlenecks because it’s typical on most shop floors. But there are many types of bottlenecks that can create productivity (and profit) loss as well as headaches for you.

There are constraints, or bottlenecks, in every process no matter what it is. Unless a process involves a single step, there will always be one step or action that takes more time. Sometimes bottlenecks are easy to spot. For example, when parts are piled up in front of the WidgetMaster XL7 waiting to be processed while machines and workers downstream are idle waiting for those parts, that machine is your obvious constraint. And it’s critical to remember that your bottleneck sets the pace for the entire process.

In his book, The Goal, Eliyahu Goldratt told the story of a group of scouts on a hike to demonstrate the effect of a bottleneck. All the hikers behind the slow kid were piled up, hoping to go faster, while those in front of him were stretched out and moving at top speed… just like the parts on either side of the WidgetMaster XL7. Relocating the slow kid in the line didn’t help since the hike (aka the process) was not complete until all scouts reached the final destination. In the same way, your process is not successful until all parts and functions have been completed.

While it’s easy to envision a group of hikers either stretched out or piled up behind the bottleneck (and you may have seen a similar situation on your own production line), not all bottlenecks are obvious. The examples of the WidgetMaster XL7 or scout troop represent physical constraints, and they’re easiest to spot. However, physical constraints are not always equipment-dependent. They can also be caused by material shortages, lack of people or lack of space.

Bottlenecks can also be caused by policies, both formal and informal. Union contracts and government mandates can also create bottlenecks. Mandated breaks or contract stipulations can affect the speed of production. Less formal company culture (“this is how we do things here” thinking) may also be the culprit in constraint creation.

Some company practices go hand-in-hand with culture and may create bottlenecks or otherwise increase waste. For example, running a non-constraint piece of equipment at top speed to reduce the manufacturing cost per piece can quickly have the opposite effect. You’ll end up with a pile of parts waiting in queue that cost you in both inventory waste and time waste.

Finally, the market itself can create a bottleneck when production exceeds sales. This is like moving the slow kid to the end of the line. The bottleneck still exists and is still affecting your profitability.

You can identify bottlenecks by long wait times (delays waiting for parts), backlogged work (the pile in front of the WidgetMaster XL7) and stress levels. High stress levels can be a good indicator of bottlenecks created by policy and practice – the ones that are much more difficult to spot.

We’ll be exploring more about unblocking bottlenecks in the coming issues.  In the meantime, Contact MPower to learn how we can help you identify your bottlenecks as the first step in reducing their negative impact to your organization.