If you manage or work in a factory, it’s likely that one of the things that keeps you up at night is the existence of bottlenecks in your production line. Do not feel alone – just about every factory faces this type of problem, regardless of what is being produced or where in the world the factory is located.
By definition, a bottleneck is “a point of congestion in a production system that occurs when workloads arrive too quickly for the production process to handle. The inefficiencies brought about by the bottleneck often create delays and higher production costs.” Wherever the bottleneck is located in the process, the result is a delay in all subsequent parts of the production line.
The good news is that once you identify the bottleneck, a solution is more often than not fairly easy to implement. It is identifying the bottleneck that can be the biggest challenge.
Responsibility for the overall productivity (and therefore bottom line) of the factory generally falls to the management team. However, if these management team members are not themselves on the factory floor watching what is happening in real time, they base their information on reports they receive. They need to analyze the data and determine at which point in the factory line a bottleneck is occurring that is holding up the whole line.
According to the Theory of Constraint International Certification Organization, there is an 80% chance that management is wrong about where a bottleneck lies. They will make an assumption about where the bottleneck is and will work from that, making changes to the production lines. But, because they are mistaken about where the bottleneck is, these changes will not fix the problem and may even make it worse.
When it comes to bottlenecks, it is critical to take the time to correctly identify (and test to be sure that it is truly correct) where the bottleneck is and why it is happening there. Once it is identified, factory management needs to be aware of what the options are and the steps necessary to fix the bottleneck.
How to Identify a Bottleneck
The easiest way to identify a bottleneck is to look at each production station and see where there are more items waiting in line to be processed. For example, if machine A processes 20 items per minute and then machine B can only process 10, after a few minutes there will be a backlog of items waiting for machine B, indicating a bottleneck.
This sounds simple, but becomes more complex when the factory has a long assembly line or when there is actually a cumulative effect. In a cumulative effect, several production stations work slightly faster than the ones further down the line so that what starts as a small batch of items waiting for processing quickly grows to bigger amount that impacts overall productivity.
Another way to confirm the presence of a bottleneck is by the throughput (total output of a machine).The total throughput of the production line is dependent on the output of the machine causing the bottleneck. By manually changing the throughput of each machine one at a time and measuring the results on overall output, it will become clear which machine is the bottleneck – the one that has the biggest impact on the overall output.
Bottleneck Identified…Now What?
Once the bottleneck has been identified, the next question is why?
Is it because the machinery is broken? Is it because the workers are not working at optimal levels? Is it because of routine maintenance schedules? Is it because of poor planning or unrealistic expectations?
Data collection and analysis will help identify the exact frequency and reasons for downtime at the bottleneck and the specific reason why will inform what the appropriate next step is to fix the bottleneck and improve productivity.
Canadian business consultant April Love gives an example of a sawmill that identified and solved two bottlenecks by gathering and analyzing data. They realized that they were running their entire line at a sub-optimal speed and that their shift-changeovers were being handled inefficiently, both of which were causing delays that were impacting overall productivity. By increasing the machines’ speed and changing the shift scheduling, the sawmill increased production by 20% and reduced their work-in-progress costs by half.
This is the type of result that you can get as well – all you have to do is take the time to analyze exactly what is happening at all stages of your production line. And remember, once you have identified and fixed a bottleneck, chances are another one will crop up somewhere else, so this must be an going process to ensure that your factory is always working at top efficiency.