Leseprobe: MES - Manufacturing Execution System (englische Ausgabe)

Table of contents 1 New ways for the effective factory...................................................... 1 1.1 Requirements for tomorrow’s manufacturing............................. 1 1.2 Production structures .................................................................. 4 1.2.1 Orientation towards metrics ........................................... 4 1.2.2 Control methods ............................................................. 5 1.2.3 Combinations of production structure and control method......................................................... 7 1.2.4 Weaknesses in traditional PPS systems.......................... 7 1.2.5 Function levels ............................................................... 8 1.2.6 Types of production ....................................................... 10 1.3 Classic IT support in production ................................................ 11 1.4 Manufacturing Execution Systems (MES) ................................. 13 1.4.1 Emergence of the MES concept ..................................... 13 1.4.2 Current standards ........................................................... 17 1.4.3 The ideal MES................................................................ 23 1.4.4 Technical requirements .................................................. 27 1.5 Vertical and horizontal integration ............................................. 29 1.6 Use of an MES system in the company ...................................... 34 1.6.1 Organizational requirements .......................................... 34 1.6.2 Technical requirements .................................................. 34 1.6.3 Economic efficiency....................................................... 34 1.6.4 Support for CIP and current certifications ..................... 35 1.6.5 Definition and tracking of objectives ............................. 36 1.7 Practical examples of potential benefits ..................................... 37 2 MES for process capability ................................................................. 41 2.1 Economic efficiency as a process property................................. 41 2.1.1 The process-oriented approach of ISO 9001/TS 16949 ................................................... 42 2.1.2 The process potential in figures ..................................... 43 2.2 The process capability of the organization ................................. 44 2.2.1 Identification of systematic errors.................................. 45 2.2.2 Systematic failure processing......................................... 46 2.2.3 Tracking corrective action.............................................. 47 VIII Table of contents 2.3 Process capability in collaboration.............................................. 48 2.3.1 Wasted work ................................................................... 48 2.3.2 Operational target agreements ........................................ 50 2.4 Process capability of information flows ...................................... 50 2.4.1 The company as a paper factory ..................................... 51 2.4.2 Interfaces without value generation ................................ 51 2.4.3 The way to paperless production .................................... 52 2.5 The process capability of flow control ........................................ 54 2.5.1 Deterministic control....................................................... 54 2.5.2 Control with feedback (closed-loop control) .................. 55 2.6 Summary ..................................................................................... 58 Literature ................................................................................................ 60 3 Added value from software.................................................................. 61 3.1 The company as information system ........................................... 61 3.1.1 Information as a production factor.................................. 61 3.1.2 Re-engineering and integration....................................... 62 3.1.3 Information processing in production ............................. 63 3.1.4 Machines as information-processing systems ................. 64 3.2 MES in the capital goods industry .............................................. 65 3.2.1 Characteristics of the capital goods industry .................. 65 3.2.2 MES in the IT software landscape .................................. 66 3.2.3 MES in the technology life cycle .................................... 67 3.2.4 MES as seen by the user ................................................. 69 3.2.5 MES as seen by the market ............................................. 70 3.3 Preparations for MES-implementation........................................ 71 3.3.1 Identification of objectives ............................................. 72 3.3.2 Systematic process development..................................... 72 3.3.3 Estimation of a return on investment .............................. 73 3.3.4 System tuning.................................................................. 74 3.3.5 Introduction of MES in the company.............................. 75 3.3.6 Operation of the MES solution ....................................... 76 3.4 Innovative technologies in the MES environment ...................... 76 3.4.1 The digitized factory ....................................................... 76 3.4.2 The digital factory........................................................... 77 3.4.3 The factory with real-time capability.............................. 78 4 MES: the new class of IT applications................................................ 81 4.1 Introduction and motivation ........................................................ 81 4.2 The current situation in the manufacturing company.................. 82 4.2.1 Tools and systems for the operative level ....................... 82 4.2.2 Manual information procurement and other tools........... 84 4.2.3 Problems in bringing together the data ........................... 86 4.3 The situation as it ought to be ..................................................... 86 4.3.1 Gapless automated data acquisition ................................ 87 4.3.2 The information point for production ............................. 88 Table of contents IX 4.3.3 The concept of the “manufacturing cockpit” ................. 89 4.3.4 Escalation management and workflow........................... 95 4.4 Outlook and further development of MES systems.................... 97 Literature................................................................................................ 98 5 Building an MES system ..................................................................... 99 5.1 Software architecture of an MES system.................................... 100 5.1.1 Basic functions ............................................................... 101 5.1.2 Data layer ....................................................................... 103 5.1.3 Application layer: business objects and methods........... 104 5.1.4 Process mapping............................................................. 105 5.1.5 The advantages of ESA architecture for MES systems ............................................................ 106 5.

1.4 Manufacturing Execution Systems (MES) 23 − Quality management − Information management 1.4.3 The ideal MES When we consider the tasks we have so far described, tasks which an MES should perform within the context of different control strategies and differ- ent kinds of manufacturing types, the question arises as to what the ideal MES is. Is there an ideal MES anyway? Throughout all manufacturing industries, “yes” will certainly not be the answer to this question. Nevertheless an attempt should still be made to sketch out the functionalities an MES should ideally have for the environ- ment of discrete manufacturing or even of batch-oriented manufacturing. The “working area” of an MES will, of course, extend from interfacing with corporate management applications as far as the deepest depths of data acquisition, communication with industrial systems and the provision of data for machine controllers or influencing the machine controllers di- rectly. This extensive operational area, which not only includes a compre- hensive range of different topics but which must also cover different time levels, ranging from days and weeks down to seconds, also calls for a tiered examination of the individual functionalities. This examination can thus be subdivided into the following areas: − The functionalities of an MES itself − Communication with corporate management applications − Communication with the manufacturing environment As a rule a PPS covers three function groups: production, quality and per- sonnel. Within these function groups powerful modules are available which can be activated and used depending on requirements. A basic system ensures that all modules are linked together in real time and furthermore provides intermodular functionalities. Another important function is acting as the information hub. In an analogous manner to these function groups in the PPS/ERP sys- tem, an MES can also be divided into three function groups. These are primarily the functionalities for production, the functionalities for quality and the functionalities for personnel allocation. To prevent these functions from appearing rather too abstract, we shall use the descriptions and in some cases the designations used in the classic definitions of the modules from which the MES developed. 24 1 New ways for the effective factory Fig. 1.10. MES function groups Function group: production The function group “production” can include the following modules: − PDA: production data acquisition Here order- and person-related times and quantities are recorded. In the quantities a distinction is drawn between conforming items and scrap and also scrap categories. It is also possible to directly record material consumption and wear and tear on operating resources or process mate- rials and associate them with the corresponding orders. The data which have accumulated over shifts, days or weeks are prepared correspond- ingly and then made available to corporate management applications. Detailed, real-time displays and analyses can be prepared in parallel with this for organizational functions in production. − MDC: machine data collection Machines or other operational resources are managed in this group. Status data can be acquired manually and automatically via comprehen- sive systematics and subsequently be assigned to resources or resource groups. The data can then be supplied here not only by conventional terminals but also by industrial bus systems. Automated registration of quantities via counters, via balances, scales and comparable equipment should also be supported. The data so acquired can then be supplied in a condensed form to corporate management as a basis for effectiveness 1.4 Manufacturing Execution Systems (MES) 25 statements but also, in their detailed form, permit analysis of points of weakness within production. − Control station, planning table These functionalities are the subject of vigorous discussion. On one hand, ERP systems via their APS functions offer planning possibilities within a shift. In the case of the control station and planning table mod- ules in an MES system the emphasis is even more on preparing techno- logically feasible plans whereby the feasibility should also be assessed on the basis of a current situation. It is a waste of time making plans whose likelihood of being put into action is relatively low. From this it follows that the more detail and precision are required for planning, the more the plan must be related to current situations. Here the detailed planning modules of an MES should not only allow manual interventions which are simple from the operator’s point of view but also offer support for fully-automated loading as well as simulation and optimization. − TRM, DNC (tool and resource management and transmission of ma- chine settings) An MES should be able to manage tools and other auxiliary materials and equipment on a technically oriented basis. It is less a matter here of managing inventory (as is necessary and normal in the field of corporate management) but much more a matter of the technical state of operating resources, of current availabilities, of managing compatibilities with machines and the qualitative evaluation of these auxiliary resources. From the direct proximity to machine data collection, possibilities also emerge for preventive maintenance and thus for being an effective means of being able to reduce the occurrence of unforeseen downtimes. − MPL: material and production logistics A particularly important point in production is those materials which are in circulation or being held in interim storage facilities. Here a material and production logistics (MPL) module helps to keep an overview and to initiate transportation activities at the right time. A function of this kind should not be confused with a warehouse management function. Instead it is exclusively concerned with WIP (work in progress) – in other words, the materials which are circulating outside the classic stor- age facility. MPL supplies information about the quantities which are currently in circulation. Function group: quality The quality function group in the sense of an operative quality assurance should not be confused with the kind of quality management offered by, 26 1 New ways for the effective factory for example, the major ERP systems and which is to be understood as a company-wide quality management system which plans and administers. − SPC: statistical process control. SPC is concerned with connecting up measuring equipment to allow the specific acquisition of measured val- ues, online comparison of the measured values against a set-point value, and the immediate output of warnings should the two values differ by earlier specified levels of tolerance. Naturally, SPC saves these random samples and permits tracking of certain trends. These trends can also be displayed directly online in the production facility and thus identify and prevent any production which might have malfunctions. − NCM: non-conformance management. Here products which are the subject of complaints are traced back on the basis of technical aspects, manufacturing conditions, and input materials. Countermeasures are in- troduced and tracked via a response measures system. − Incoming goods. In this context, the incoming and outgoing goods func- tion is less the rating of suppliers as is normal in QM but rather the spe- cific registration of delivered goods or of dispatched goods, the verifica- tion of batch numbering, and an online alarm facility if certain values are out of tolerance. − Inspection equipment management is directly comparable with TRM from the function group “production”. Here inspection, measuring and test equipment is managed and it is ensured that they meet the required standards and that they can also be used for the corresponding tests and inspections. This information must, of course, be available with imme- diate access during the inspection and testing procedures. − PDP. An unusual feature in this context is the process data processing module. This implements the proposition that quality is not simply a property of the product but that quality also depends on the circum- stances of production. For example, the pressures and temperatures used in the production process are of decisive importance to quality and for this reason an MES should also have the capability of acquiring process values directly, verifying them against tolerance or intervention limits, and in the event of errors recommending countermeasures. Function group: Human Resources − Staff work time logging. Throughout its history the human resources function group has always been very closely attached to corporate man- agement. A series of elegant simplifications emerges for personnel allo- cation and personnel management in production when production- related personnel handling is mapped into the MES system. The staff 1.4 Manufacturing Execution Systems (MES) 27 work time logging module covers clocking-in/clocking-out data as well as absence times and can also keep month-based time accounts where this would be useful. This approach would be particularly ideal when labor capacities in production facilities play an important role (as is very often the case) and these labor capacities have to be scheduled in a timely and efficient manner. − Incentive wages. Staff work time logging in the MES deploys its strengths when bonus systems need to be implemented.