MOM or ERP enhanced with a production management module - which to choose?

What is ERP and what is MOM

When we say 'ERP', most manufacturers know what system we are talking about. It is enterprise resource planning (ERP) software. It helps to run the entire company, supporting processes in finance and accounting, human resources, supply chain, services, acquisition and more. It is used by companies in a wide range of industries - services (commercial, financial, hospitality, education, transport, public administration, healthcare, etc.) and manufacturing (food, metal, plastics, etc.).

"MOM", on the other hand, is still a concept that is not fully understood. Its name comes from Manufacturing Operations Management. It is software dedicated to manufacturing companies and designed for the complexity of manufacturing processes. It will not benefit schools, banks or hotels in the same way that they use ERP systems.

ERPs often fail in manufacturing

Why were MOM systems developed when ERPs can supposedly do everything? ERP vendors often offer modules designed for manufacturers that can plan and schedule production, collect production data, manage production routings and technologies.

Unfortunately, despite such promises, ERP systems in many cases fail to cope with the challenges of complex manufacturing ecosystems. In many cases, factories using dedicated manufacturing modules within ERP systems, have asked us for help because they needed to schedule and plan in Excel. Major ERP vendors such as SAP, although they have modules dedicated to production scheduling and planning in their offerings, admit that they integrate their systems with solutions designed from the ground up strictly for manufacturing in order to mirror what is happening on the shop floor (see here).

Why ERP production modules fail

An explanation of the differences between ERP and MOM at a very general level, according to ISA 95/IEC62264, can be found in this article. As a reminder - ISA (The International Society of Automation) is a non-profit international association of engineers, technicians, business people, teachers and students who work, study or are interested in automation and related fields. It is one of the most important professional organisations in the world for setting standards and educating automation professionals. Instrumentation and automation are among the key technologies used in almost all industrial production. Modern industrial production is a complex interaction of many systems. Instrumentation provides the regulation of these complex systems using a wide variety of measurement and control devices. Automation provides programmable devices that allow greater flexibility in the operation of these complex production systems. The ISA standard makes a clear distinction between MOM (level 3) and ERP (level 4), assigning completely different roles to these systems. Among other things, MOM includes the MES (Manufacturing Execution System), which is a system for collecting production data in general, and APS (Advanced Planning and Scheduling), which is a system for advanced production planning and scheduling. According to the ISA, MOM is the link between ERP and Level 2 systems, i.e. SCADA (Supervisory Control And Data Acquisition), which supervise the course of a technological or production process.

Listing the detailed differences between ERP and MOM would require an analysis of the individual data models and underlying technologies, and these are usually not public. In our experience, however, we know that no ERP will be able to replicate manufacturing processes in a dynamic environment as well as an MOM system. Examples of problems that most ERPs cannot cope with are the dynamic inclusion in scheduling and planning of so-called "joins" (i.e. combining production tasks from different orders to share resources), the traceability of single pieces in lot-size-one production, multi-variant dynamic analysis of production scenarios or managing changes in demand or supply.


Sometimes manufacturers believe that it is better to choose an ERP system with a production module, because there will be no need to integrate two different systems. And it is well known - integration can generate a mass of problems (different data structure, some data may be lost as a result of integration, significant delays in data processing may occur). From our point of view, this argument is completely wrong for two main reasons:

  1. If the ERP system developer bases its manufacturing module on a data model common to the entire ERP system (i.e. it remains at level 4 of the ISA 95/IEC62264 model), then indeed integration is unnecessary, but also, as we explained earlier, such a module is not up to the task of managing production at schedule and shop floor level.
  2. If an ERP developer develops a new data model for the production module and uses other technologies to better represent the production processes to get closer to level 3 according to the ISA model, they actually have to carry out the integration of the production module with the rest of the ERP system. This means that, from a technical point of view, 2 separate systems have been created that need to be integrated, just as the MOM system needs to be integrated with ERP. In addition, the disadvantage of such a solution is that the production module is designed from the beginning for the ERP with which it will be integrated. This results in the ERP developer not focusing on mirroring the manufacturing processes, but trying to adapt these processes to the requirements of the ERP system. In addition, such modules added to ERP are often too difficult to implement, maintain and use (because their foundations lie outside of manufacturing), and their release cycle (i.e. the publication of new improved versions) is long because it requires a number of factors to be taken into account and complex testing to be carried out.

The MOM system is designed from the ground up to support production. It contains all the functionalities needed to handle even the most complex production cases. Contact points with ERP are provided so that integration with ERP does not interfere with production management in a dynamic environment where the only certainty is frequent changes (breakdowns, reprioritization of production orders, quality errors etc.).


Another argument of ERP providers selling manufacturing modules is the slogan 'everything from one supplier', i.e. one contract, one point of contact, one ticketing system, one invoice. And indeed - some of this promise may be true, but certainly not all of it. ERP software vendors operate across teams, departments and often even different organisations within the same corporation. There is never a single person with in-depth knowledge of both handling the value tax issues, scheduling production using on-site renewable energy and maternity leave accounting. These are all separate areas of expertise, requiring separate consultants and separate development teams. In IT corporations, the different areas are often dealt with by separate business units, which sign separate contracts and issue separate invoices. Customers' experiences with separate modules of ERP also vary, e.g. an ERP vendor may have implemented a finance and accounting system and HR system brilliantly, but completely failed with a billing and CRM system.

Today's times, with every field evolving rapidly and requiring increasingly in-depth knowledge, force us to use multiple solutions for a variety of applications. The IT industry is a perfect example of this. Years ago, a given solution was programmed from A to Z in a single language. Today, a range of software languages, technologies and off-the-shelf components are used, because it does not pay to reinvent something that someone else has done best, and the topic of integration appears on every modern software supplier's website. Just like in life - there are areas where one integrated solution makes sense (e.g. a fridge with a built-in freezer, an ERP combining HR, billing and a finance and accounting system, or a MOM combining an APS with a MES), and there are areas where it is not worth it to forcefully combine different functionalities (e.g. a fridge with an oven or a MOM with an ERP).

Examples of Azumuta system integrations (Integrations Archive - Azumuta):

Examples of Katana system integration (Integrations - Katana):

Advanced production management - MOM only

In summary, production modules in ERP systems can support some areas of production management and handle simple production cases. For more demanding production processes, they are insufficient. Properly distinguishing between areas where all-in-one solutions are needed and those where specialised solutions are needed is the key to successful digitalisation and automatisation of an organisation. Integration between different systems can be seamless for users, provided the points of contact are properly selected and the areas of support by different systems well defined.

Our MeMOM system is a specialised cloud-based platform for managing production operations. Each of its authors has several years of experience in developing this type of software and this is the third generation of APS they have produced. As a result, there are no mistakes in our data model and the technologies used that were made in the 2 previous generations. This is a rare thing in the market as these types of systems have a long life cycle of around 15-20 years. As a result, we feel we are experts in what we do and have not encountered a production case to date that we have not been able to replicate and handle. We can help you identify areas that only MOM can handle.

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