Today’s manufacturing and industrial environment is increasingly becoming more globally competitive
Companies need to continually change the way they do business if they are to remain in existence. A few years ago the emphasis may have been on such things as total quality management and even just-in-time, but today we have enterprise resource management (ERP), management resource planning (MRP), warehouse management systems (WMS), product lifecycle management (PLM), supply chain management (SCM) and even customer relationship management (CRM). All this on top of such additional necessities like automation and such things as scada systems in the process environment.
Background to MES
Unfortunately many of these systems operate in isolation and outputs are not readily available at levels such as management. Also many published articles have commented on the dividing line between plant-floor systems and the rest of the enterprise. After all 'ERP vendors do not understand plant-automation vendors and vice versa' according to one international consultant.
The solution for manufacturers as described in the literature by many experts is to operate a real time enterprise (RTE), of which the core is a manufacturing execution system (MES). While financial, materials, planning and logistics personnel have for a long time used computer applications to improve the accuracy and timeliness of their work, MES now provides the same benefits for operations. MES focuses on plant activities and provides the realtime information needed to react to events as they occur, combining what is happening with what should be happening to meet the actual objectives. The MES is critical to the RTE as it is the source of virtually all the manufacturing related data and as the MES is directive it can immediately change execution on the shop floor. This realtime capability enables the optimum use of assets and resources for the highest manufacturing utilisation and efficiency possible. The bottom line is thus lower operating costs and a higher return on assets. In addition, full integration between systems eliminates human error and should problems be detected, for example, in a process plant, the system can be used to alert operations personnel automatically, allowing them to rectify the issues timeously.
Just what can an MES do for a manufacturer?
It will allow the tracking of a specific customer order at unit and component levels, allowing identification of where each unit is in the production cycle and what materials are required and when. This obviously allows companies to reduce inventory, while allowing customers to be informed of exactly when they can expect delivery. As the MES allows companies to maintain records of products and processes by unit, information can be gathered on test and quality results, operators in charge and whether the product is being built in compliance with requirements. This allows manufacturers to hone in faster and accurately when changes are required. It will also provide traceability of all the parts and subassemblies supplied by third parties (contract manufacturers). Again this allows the final manufacturer to optimise his own materials availability.
Another benefit of an MES is that by collecting detailed employee activity information, management can gain new insights into the effective utilisation of labour on the shop floor. Detailed accounting for the full employee day, including work time, break time and down time, is recorded and shared with the human resource system. This then provides an accurate picture of the productivity of employees and the effectiveness of shop floor management.
Another area where the MES is critical is where the Internet is being used to drive a build-to-order manufacturing model. As a result, such companies (an example is computer manufacturer Dell) have their front-end Web presence supported by a back end that goes all the way to the plant floor.
One published study, which was launched to establish whether facilities using MES enjoy performance advantages over other plants, and the results clearly indicated that they do. The published figures show cost reduction (34% over three years), yield improvements (15%), productivity improvement (32% higher value-add per employee) and energy consumption reduction (57%) amongst other improvements.
There is an association called the Manufacturing Enterprise Solutions Association that addresses the issue of MES. Besides having many international manufacturers as members all of the major information systems technology providers, including SAP, Siemens MES, Wonderware, Rockwell Automation and Citect are also members.
Where MES is today
Installation of MES systems internationally and within South Africa is proceeding apace as more and more companies realise the competitive advantages offered. In a way the implementation was drowned by the effects of Y2K, as from then until about 2003 companies were still bedding down their ERP systems. The problem regarding installation of the many available MES solutions is not one of technology (that is available) but of people.
In many operations two IT departments have evolved over time, these addressing firstly business processes and then managing information on the shop floor. The latter is not often seen as critical for the IT department and they need to be convinced of the benefits. Similarly the financial people only really look at their reports on a monthly basis and do not believe that there is a need to look at what is happening on the shop floor in realtime. They need to understand the benefits and many MES providers now establish a benchmark before and after installation and the figures have astounded top level management.
While the production and engineering people realise the benefit of having an MES, unfortunately this message does not reach top management as the technologists do not talk in rands and cents. So once again it cannot be emphasised enough that people from IT and accounting to instrumentation and engineering need to get together and talk.
What companies must do to be successful is to establish a set of business objectives and then find out what makes these happen at shop floor level in realtime. As an example, if quality is an issue this would be one of the core parameters to measure at every stage. An early alert to a quality problem prevents additional added value to be added to a product that has finally to be discarded. An analogy that Mike le Plastrier uses is that in driving a car we look at only a few critical gauges as otherwise we cannot control the vehicle and there would be information overload.
Similarly, in the plant there are only a few pieces of critical information required and these would be different at all levels from plant floor right up to top management. Another major advantage is that automatic information is truthful. When a human is used to input data there can be many influences on what they actually enter, hoping for example that a downturn in production can be made up during the next shift.
Some applications
As regards Wonderware they believe that the MES solution should be driven from the shop floor environment upwards. In a green fields project they would use their ArchestrA Industrial Application Server as the automation infrastructure. ArchestrA allows a physical model of the plant to be created and this is the meat for the MES system. What one then does is to build of top of this infrastructure so that all events can be recorded with context-based information. The standard S95 schedule of deliverables would typically be used. In fact the development of such standards as S95 have gone a long way to allowing information integration between the top floor and the shop floor. At the end of a shift all the events can be reported back to, for example, the SAP system. This approach in the automotive industry for example would provide traceability on critical parts such as brake systems and airbags and in the event of a recall the manufacturer would know exactly which vehicles were affected.
Legacy systems are not a problem with the Wonderware solution. A large Russian plant recently had an MES system installed by the company. At that time it operated three different DCS and two different PLC systems in the processing plant. The ArchestrA model was installed on top of that entire infrastructure and operates in the same way. In this case there was no need to go down to the actual shop floor level but the company may with time migrate the total Wonderware solution downwards.
The Holy Grail would of course be a dynamic package that would fit all sizes and types of plant. At the present moment that is a dream as companies are so variable but it could be something that could happen in the future. Of course any good MES is adaptive and makes allowances for changing requirements, although any MES is still better that what companies would have without it.
While Wonderware appears to be capable of handling legacy systems every industrial plant is different and the purchaser of the MES technology needs to ensure that what they purchase is compatible with their legacy infrastructure. If not then putting in a genuine realtime MES may become a very expensive exercise.
Conclusion
There is absolutely no doubt that MES is here to stay and acceptance of its need is growing rapidly both within South Africa and internationally. Although many industries are still using human input the protagonists of MES are coming up with good arguments, especially the one that to remain globally competitive you have to be more accurate in realtime with plant information.
Thanks to Mike le Plastrier (Futuristix, EOH) for his input to the content of this article.
Dr Maurice McDowell has many years' experience as a technical journalist, editor, business manager and research scientist. His third party analyses of world-class companies and processes, as well as his insight into industry and technology trends are well respected.
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