We are often asked what companies (or types of companies) are using OEE as part of their daily operations. While our focus has been primarily in the automotive industry, we are highly encouraged by the level of integration deployed in the Semiconductor Industry. We have found an excellent article that describes how OEE among other metrics is being used to sustain and improve performance in the semiconductor industry.
Somehow it is not surprising to learn the semiconductor industry has established a high level of OEE integration in their operations. Perhaps this is the reason why electronics continue to improve at such a rapid pace in both technology and price.
The article clearly presents a concise hierarchy of metrics (including OEE) typically used in operations and includes their interactions and dependencies. The semiconductor industry serves as a great benchmark for OEE integration and how it is used as powerful tool to improve operations.
While we have reviewed some articles that describe OEE as an over rated metric, we believe that the proof of wisdom is in the result. The semiconductor industry is exemplary in this regard. It is clear that electronics industry “gets it”.
As we have mentioned in many of our previous posts, OEE should not be an isolated metric. While it can be assessed and reviewed independently, it is important to understand the effect on the system and organization as a whole.
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How to Calculate OEE for Single Machine and Multiple Parts.
Flexible manufacturing provides the advantage of producing many different parts on the same piece of equipment. The same is true for processes such as stamping presses, molding machines, or machining operations.
The first question most often asked is, “How do we calculate OEE for a piece of equipment that is capable of manufacturing multiple parts?” The overall OEE for a stamping press, molding machine, machining process, or other “multipart” process is easily calculated using the same formulas presented in our previous posts “How to Calculate OEE” and “Practical OEE“.
We presented three machines running at various rates and producing unique products. We demonstrated how to calculate the OEE for each part individually and for all parts collectively. The machines A, B, and C could very easily be parts A, B, and C running on one machine. The application of the OEE formulas presented for these three machines is the same for multiple parts running on the same machine.
We have prepared two Excel spreadsheets that demonstrate how to calculate OEE for a single machine that produces multiple parts. We have also created a separate Excel spreadsheet that will show you how to calculate OEE for Multiple Departments and Multiple Machines running Multiple Parts.
Calculating OEE for any period of time, department, or group of equipment is a simple task. With the understanding that OEE measures how effectively Net Available Time is used to produce good parts at the ideal rate, the formula for any OEE calculation follows:
OEE (Any Category) = Total SUM of IDEAL Time / Total SUM of NET Available Time
Once this basic premise for OEE calculations is clearly understood, any combination of OEE summaries can be prepared including OEE summaries by Shift, Operator, Manager, Division, Process, and Process Type.
We are currently offering our Excel OEE Spreadsheet Templates and example files at no charge. You can download our files from the ORANGE BOX on the sidebar titled “FREE DOWNLOADS” or click on the FREE Downloads Page. These files can be used as is and can be easily modified to suit many different manufacturing processes. There are no hidden files, formulas, or macros and no obligations for the services provided here.
Multipart OEE – Confronting the Challenges
Most manufacturing environments are challenged with the task of minimizing inventories requiring more frequent change-overs or setups. By far, the greatest challenge of multipart equipment is managing the change-over process and is usually reflected in the OEE Availability factor.
We recommend including setup or change-over time as part of the unplanned downtime calculation. Then, by definition, one method to improve Availability is to reduce change-over or setup time. Reductions in change-over time will also be reflected by improved Availability. The Availability factor is now a useful metric for tracking improvements.
According to our definition, change-over time or setup time is measured from the end of the current production run (“the last good part made”) to the start of the next production run (“first good part produced”). We have worked with some manufacturers that decided to do change-overs on the off shift so that they could avoid the down time penalty. They clearly didn’t get the point – deferring the time when the change-over is performed doesn’t change the time required to perform it.
Several programs such as SMED (single minute exchange of dies) are available and, when coupled with best practices for quick die change (QDC) or quick tool change techniques, can greatly reduce the time lost during your tool change events.
We will consider posting best practices for SMED or QDC and would welcome any reader comments in this area.
We always welcome your feedback and comments. Feel free to send us your questions or comments to email@example.com