A very good way to understand the role of Manufacturing Execution Systems is the discussion I had some years ago with a customer.
It all started when the customer complained “When I look in SAP I am wealthier, then when I look at my Warehouse”.
Background to this was an implementation of SAP at this customer about one year earlier. To fetch the production data into SAP, the Machine operators had to punch in the production details on a terminal connected to SAP. However, since this was an extra burden for the machine operators and the machine operators had no interest in the requested production details, they just entered non sense data into SAP, just to satisfy the SAP rigid data entry form.
Once the customer understood where the (huge) differences came from, he asked me to propose a workable solution to connect to their SAP system, hence the need for a Manufacturing Execution System (MES). By directly interfacing with the production machine, rather than relying on the numbers provided by the operators, SAP was fed with actual and accurate production data.
Normally SAP processes salesorders as one entity, The installed MES can accept these salesorders and handle them irrespective whether the production of that order involves one production step or multiple production steps, the Manufacturing Execution System do facilitate scheduling functionality, for orders which have to run on multiple production machine before complete0..
In the days before we were aware of Manufacturing Execution Systems, there was already some need for data from the Process- and Production Control systems to flow to other systems. This was often handled as a simple interface (Serial or Parallel).
Over time the functionality of this simple interface has grown into what we now call Manufacturing Executing Systems (MES). Manufacturing Execution Systems were first mentioned in 1991.
The scope of Manufacturing Execution Systems has been defined by MESA (mesa.org) in the MES Honeycomb model and covers 11 distinct functions.
The figure shows the surroundings of the MES, like Controls and ERP system. Which basically covers the story mentioned in the beginning of this article.
Defined in the ISA 95 standard, MES is now often refered to as Manufacturing Operations Management (MOM). But somehow MES is still the term which rings a bell.
Interested in the benefits Manufacturing Execution Systems can bring to your plant, contact Visschers-Consulting to discuss.
