One typical “entry point” for manufacturing execution systems (MES) is often the desire to have operational metrics such as OEE (overall equipment efficiency). OEE is expressed as a percentage and is calculated by multiplying three other metrics together (A x P x Q) where:
- A is Availability: Did the process run when scheduled to run?
- P is Performance: Did the process run at the full rate while running?
- Q is quality: Did the process produce products without defects?
With today’s automation, these values (lost production) can typically be calculated in real time. This can be done for any type of process, discrete, continuous, batch or hybrid processes. However, the real value in these metrics is to understand exactly what the cause of any lost productivity was. In the best case, this information also can be provided from the control systems but if need be, it can be provided by operators or engineers.
In addition to process control signals, the system making these calculations will typically need to have data about:
- The production schedule (should the process be running now)
- What product is running now (since the recipe and/or rate may vary by SKU)
- The results of quality lab samples
Having this data would also allow for reporting based on shift or product.
Additionally, a system that collects all of this data can now perform one of the core functions of MES – tracking and managing production orders in real time. Production order management is a natural extension of OEE. Once this data is in place, it should be simple to answer questions like:
- What is the status of each piece of equipment right now?
- What is running on each piece of equipment, right now?
- How far along in the production is any order, batch or lot?
Extending this to other aspects of production order management could be next. Creating electronic batch records (EBR) or otherwise capturing everything about a production order can be done by integrating this data with raw material addition (creating a genealogy), conditions during manufacturing (from the operator or control system) or by collection observations and actions taken. If the process has steps, the order workflow can now be automated, showing the operator where to send the material next without the use of paper records. Knowing what is queued up on a machine or connecting to serialization for track and trace is also a natural next step.
These are all examples now of what MES can do - digitizing operations and unifying communications on the plant floor and beyond. Actions like operator journaling and the automated scheduling and/or triggering of tasks can be tied to production records or historized for a complete record of the activities. Notifications and alerts can put information about exceptions into the right hands at the right time.
Other significant capabilities can now be implemented using your MES – statistical process control (SPC), energy management, critical equipment tracking and monitoring, and operator qualifications tracking just to name a few. Your MES has become a part of the core of your manufacturing capability. Interfacing it with your ERP, your lab systems, your document management systems or your maintenance systems will be next (if that has not already happened).
If you are just starting this journey and considering OEE, take the time to think into the future and pick a software platform that will be able to take you beyond OEE and into the world of MES. The value of features, functions and capabilities that MES can provide for your manufacturing operations is likely enormous. You will want to be positioned to get it.
Read our latest white paper, The Evolution of MES, which examines the advancement of MES over the past three decades and how you can prepare for what’s coming next.