Some aspects of system design for production management in the rolling-mill industry

Case studies in copper-alloy rolling mill companies showed that existing planning systems suffer from numerous shortcomings. Where computerised systems are in use, these tend to simply emulate older manual systems and still rely heavily on modification by experienced planners on the shopfloor. As the size and number of orders increase, the task of process planners, while seeking to optimise the manufacturing objectives and keep within the production constraints, becomes extremely complicated because of the number of options for mixing or splitting the orders into batches. This thesis develops a modular approach to computerisation of the production management and planning functions. The full functional specification of each module is discussed, together with practical problems associated with their phased implementation. By adapting the Distributed Bill of Material concept from Material Requirements Planning (MRP) philosophy, the production routes generated by the planning system are broken down to identify the rolling stages required. Then to optimise the use of material at each rolling stage, the system generates an optimal cutting pattern using a new algorithm that produces practical solutions to the cutting stock problem. It is shown that the proposed system can be accommodated on a micro-computer, which brings it into the reach of typical companies in the copper-alloy rolling industry, where profit margins are traditionally low and the cost of widespread use of mainframe computers would be prohibitive.

An analysis of the effectiveness of a behavioural based safety intervention in a UK paper mill

This research examines a behavioural based safety (BBS) intervention within a paper mill in the South East of England. Further to this intervention two other mills are examined for the purposes of comparison — one an established BBS programme and the other an improving safety management system through management ownership. BBS programmes have become popular within the UK, but most of the research about their efficacy is carried out by the BBS providers themselves. This thesis aims to evaluate a BBS intervention from a standpoint which is not commercially biased in favour of BBS schemes. The aim of a BBS scheme is to either change personnel behaviours or attitudes, which in turn will positively affect the organisation's safety culture. The research framework involved a qualitative methodology in order to examine the effects of the intervention on the paper mill's safety culture. The techniques used were questionnaires and semi structured interviews, in addition to observation and discussions which were possible because of the author's position as participant observer. The results demonstrated a failure to improve any aspect of the mill's safety culture, which worsened following the BBS intervention. Issues such as trust, morale, communication and support of management showed significant signs of negative workforce response. The paper mill where the safety management system approach was utilised demonstrated a significantly improved safety culture and achieved site ownership from middle managers and supervisors. Research has demonstrated that a solid foundation is required prior to successfully implementing a BBS programme. For a programme to work there must be middle management support in addition to senior management commitment. If a trade union actively distances itself from BBS, it is also unlikely to be effective. This thesis proposes that BBS observation programmes are not suitable for the papermaking industry, particularly when staffing levels are low due to challenging economic conditions. Observers are not available when there are high hazard situations and this suggests that BBS implementation is not the correct intervention for the paper industry.

A knowledge-based system for process planning in a seamless steel tube plant

The thesis describes the work carried out to develop a prototype knowledge-based system 'KBS-SETUPP' to generate process plans for the manufacture of seamless tubes. The work is specifically related to a plant in which hollows are made from solid billets using a rotary piercing process and then reduced to required size and finished properties using the fixed plug cold drawing process. The thesis first discusses various methods of tube production in order to give a general background of tube manufacture. Then a review of the automation of the process planning function is presented in terms of its basic sub-tasks and the techniques and suitability of a knowledge-based system is established. In the light of such a review and a case study, the process planning problem is formulated in the domain of seamless tube manufacture, its basic sub-tasks are identified and capabilities and constraints of the available equipment in the specific plant are established. The task of collecting and collating the process planning knowledge in seamless tube manufacture is discussed and is mostly fulfilled from domain experts, analysing of existing manufacturing records specific to plant, textbooks and applicable Standards. For the cold drawing mill, tube-drawing schedules have been rationalised to correspond with practice. The validation of such schedules has been achieved by computing the process parameters and then comparing these with the drawbench capacity to avoid over-loading. The existing models cannot be simulated in the computer program as such, therefore a mathematical model has been proposed which estimates the process parameters which are in close agreement with experimental values established by other researchers. To implement the concepts, a Knowledge-Based System 'KBS- SETUPP' has been developed on Personal Computer using Turbo- Prolog. The system is capable of generating process plans, production schedules and some additional capabilities to supplement process planning. The system generated process plans have been compared with the actual plans of the company and it has been shown that the results are satisfactory and encouraging and that the system has the capabilities which are useful.