Structured methodology for the selection and effective implementation of manufacturing control systems A.K. Kochhar K. Oldham S.M. Thacker Indexing term: Manufacturing control systems Abstract: All manufacturing companies, irrespec- tive of their size, make use of appropriate manu- facturing planning and control systems. Very often such systems are computer-based, involving con- siderable effort and the expenditure of large amounts of money. Yet the whole process of selec- ting the type of manufacturing control system which should be implemented in a given environ- ment remains unstructured. The paper describes a structured and industrially validated methodology for the selection and implementation of manufac- turing control systems. A reference model, based on complexity, uncertainty, flexibility and company culture characteristics, is used to assess the need for and the difficulties associated with the implementation of particular types of manufac- turing control systems in a given environment. A gap analysis approach is used to assess the dis- parities between the prerequisites for the effective implementation of a given type of manufacturing control system and what actually exists in a given environment. The structured-help system shows how to overcome the problems identified at the gap analysis stage. The complete methodology ,and the associated knowledge bases have been implemented in a computer-based system. 1 Introduction Production and inventory control today without the detailed assistance of computers is virtually inconceivable in almost all types and sizes of manufacturing companies. It is now generally well recognised that the process of implementing computer-aided manufacturing control systems in different manufacturing environments is very complex, time-consuming and costly. The level of success is relatively low, as is borne out by many surveys, which indicate that only about 10% of computer-aided manu- facturing control systems can be regarded as truly effec- tive [l, 21. The reasons for this lack of effective implementation are well documented in the literature [3, 0 IEE, 1995 Paper 2153A (15, C9), received 1st February 1995 A.K. Kochhar IS with the Manufacturing Division, Department of Mechanical Engineering, UMIST, PO Box 88, Manchester, MM) IQD, United Kingdom K. Oldham and S.M. Thacker are with Lucas Applied Technology, PO Box 52. Dog Kennel Lane, Shirley, Solihull, B90 4JJ, United Kingdom IEE Proc.-Sci. Meas. Technol., Vol. 142, No. 5, September 1995 41. One very important factor is a mismatch between the real requirements for manufacturing control and the system actually implemented. Furthermore, there is a wide disparity between the prerequisites for effective implementation of a manufacturing control system and what actually exists in a particular manufacturing environment [SI. A wide gap can lead to poorly imple- mented systems. In recent years, there have been a significant increase in the numbers and types of computer-aided manufac- turing control systems which can be implemented by a manufacturing organisation. The traditional material requirements planning (MRP) and closed-loop manufac- turing resource planning (MRPII) philosophies have been augmented by the pull (Kanban) control system, just-in- time (JIT) manufacturing philosophy and the finite capacity planfling and scheduling approach, best exem- plified by the optimised production technology (OPT) system. All these philosophies have been packaged into appropriate general-purpose computer software pack- ages. Increasingly, manufacturing companies make use of such off-the-shelf computer software packages for the implementation of computer-aided manufacturing control systems instead of developing their own solu- tions. 2 Selection and implementation of manufacturing control systems A major difficulty in the selection and implementation of effective control systems is that the whole process of arriving at the detailed system requirements is faulty. Most companies make use of the traditional ‘systems analysis’ techniques to arrive at the perceived require- ments [6]. This involves dicussions with potential users, and the managers of different departments, to determine the requirements for the manufacturing planning and control systems. Frequently, this process leads to infor- mation flow and control requirements which reflect, in the main, the recently encountered problems. In other situations, the potential user requirements vary from very little need for information to almost every conceivable item of information. System/software suppliers attempt to match the so-called user requirements to the facilities in the available packages. There is no structured discipline around the way in which the manufacturing control systems are selected. Also, there is no method to point to critical issues. Frequently, the suppliers provide solutions which are the easiest to implement. In many such situ- ations, the resulting computer-aided manufacturing 411