MES versus ERP – similarities and differences. Why one system does not replace the other?

29 August 2018

The ERP systems have become the same standard as other IT business solutions. As a result of growing popularity some suppliers started to present them as ideal tools for managing the entire company, including manufacturing. Can ERP modules really replace the MES systems within this scope?

While searching for an answer to this question, it is worth analysing the functionalities and possibilities of these both tools. We should be aware that the ERP systems are superior solutions and they do not cover the production activity as deeply as the dedicated MES systems.

 

FunctionERPMES
It settles production and materials useYESNO
It generates accounting documentsYESNO
It interferes with the production courseNONO
It collects data on ordersYESYES
It presents a list of orders to be fulfilledYESYES
It schedules productionNONO
It plans the sequence of ordersNOYES
It predicts the time of order fulfilmentNOYES
It visualises the current process efficiencyNOYES
It calculates current OEE ratesNOYES
It optimises the use of manufacturing capacityNOYES
It informs on the production progressNOYES

 

As the table provided above demonstrates, ERP does not fulfil tasks strictly related to manufacturing processes. These are tools for the settlement and overall management of the company’s assets but they do not actually support taking decisions concerning manufacturing optimisation. Even the modules offered, dedicated to the manufacturing area, will not be able to visualise the process appropriately and connect directly with the machine park.

The ERP systems are undoubtedly an IT base of contemporary companies but they cannot be treated as comprehensive solutions which aid the conducting of a business from A to Z. Although some suppliers try to present them in such a light, the ERP cannot guarantee three most important possibilities of MES systems, dedicated to production:

 

  1. The reflection of the entire manufacturing process – a function fulfilled by the MES system which supports taking decisions on the improvement of efficiency in a specific localisation and moment of the entire process. In this way you can identify carefully the problems affecting the low value of OEE and take effective measures to eliminate them.
  2. Direct connection with machines – MES systems are integrated directly with a machine park and they collect data directly from machines and devices. The ERP systems are not integrated with devices and a machine park.
  3. Data visualisation in real time – it is an outcome of the already mentioned direct connection of the IT system with a machine. Thus, data are accurate and up-to-date at any time (updating in real time). This is one of the typical MES system properties which make them an irreplaceable tool in collecting data on production processes.

Both the ERP and MES systems have important tasks to fulfil in each manufacturing site. But you must remember that they are not exchangeable because these are not substitute solutions. These are complementary solutions. A vision of using one tool in the entire plant may seem attractive but it is not practical. Sooner or later, companies which decided to implement such an experiment, admit that the ERP in the production area simply does not work well and does not bring in desired outcomes in the form of efficiency boom and higher OEE. A situation changes completely when both solutions are integrated and they are used together. Such an approach should be applied because it guarantees the best effects possible.

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