MES 101 – Performance Management
Welcome to our MES 101 series. We are going to cover the basics of a variety of MES components. You will get an overview of what is available in an MES implementation, how to leverage each piece in your process, and how you will get an ROI on the investment.
The first piece of most Manufacturing Execution Systems or MES implementations is Overall Equipment Effectiveness or OEE. OEE is a favorite key performance indicator (KPI) used to distill process availability, production performance, and overall quality into a single number. Before we dive into OEE, each of these areas deserves some attention.
In the last installment of MES 101, we covered Downtime Tracking. In this post, we will talk about Performance. Performance is the ratio of the parts produced multiplied by the ideal run rate to the total runtime of the process. This tracks the overall performance of the process against its designed capabilities.
Figure 1: Performance
Key Performance Indicator, Not Key Performance Answer
Performance is a way to understand how the process is performing vs. how it could function under ideal conditions. The things most negatively impacting performance are idling/minor stops on a line and overall slowdown.
Idling is a condition where the line is not considered to be down but is not producing the product. Maybe the raw material feeding the line is slow to make its way to a machine because a conveyor is not operating at optimal speed. The machine can’t make as much product as designed because there isn’t enough to process.
Information Is Not Valuable in a Vacuum
In the Downtime Tracking post, we talked about keeping things simple and coming up with a list of the top 5 downtime reasons. While downtime events have a distinct start and end time, a variety of factors impact Performance. While Downtime lowers the quantity we can produce, Performance is only tracked for how long the machine was running. This means we won’t have a direct correlation between downtime and performance. As a result, we will need to use other tools at our disposal to understand how to improve performance.
The first thing we can do is compare performance across different periods of time for the same product. Let’s assume one cause of performance loss is machine wear and tear. Blades dull, belts start to sag and slip, and bearing lubrication begins to degrade. If we looked at the performance on a machine today vs. the same amount of runtime a year ago, it will likely be lower. If we then compare the performance differences between prescribed maintenance schedules and actual work orders, we can build a picture of how maintenance affects performance and how regular maintenance can improve performance.
We can also take a look at operators using the equipment and track the setpoints for any given production run. In most facilities, different operators will have a preferred range of setpoints and may change them when they start their shift. This can impact performance positively and negatively. Without tracking the performance, it is difficult to understand how setpoints changes affect production. Once you begin monitoring performance, you can understand the ideal setpoints for the machine, and build recipes to make sure your operators use the ideal setpoints for every product you make.
One of the best uses of the performance metric is tracking it over time. Trending performance over time will show the health of your equipment. As you see slowdowns you can start to focus on preventative and predictive maintenance. If you see a spike high or low on a given day you can dig into the specifics of who was working, what raw material batches you were using, and anything else that might have happened to cause the spike.
Improving performance requires a deeper understanding of your process compared to reducing downtime. It also requires correlating additional data beyond only the calculation presented above. This isn’t to say tracking performance isn’t useful. However, it is not the first thing you should tackle if you want to see a fast ROI on your investment in OEE.
Stayed tuned for next week’s installment where we will cover the Quality component of OEE.