Simulation and optimisation of a specific flexible manufacturing system.

As current market competition evolves, most companies intend to increase their options for product customisation and accelerate their product upgrading. Correspondingly, manufacturers have to face the increasing size of product family, shortened product life cycle or rapid product/process change. Therefore, Flexible Manufacturing Systems (FMS) have been introduced that uses advanced machines and efficient transport systems to produce multiple products at the same time. However, an FMS can be complicated to manage because of the increased variability in products and processes. The research aims to develop manufacturing simulation and optimisation techniques for a FMS. This research will integrate Discrete Event Simulation (DES) and multi-objective optimisation approach to address the complexity and flexibility within an agile manufacturing environment. Due to the complexity of FMS, most current FMS optimisation research has engaged with FMS production problems separately without considering other inter-related problems in the same system such as dealing with operation sequence problem without considering Level of Flexibility (LoF), thus it is hard for the solution to provide a prospective impact for the whole system. There are very few real-world FMS implementations that are available to literatures, making it difficult to build and verify the models within a complete ecosystem. Consequently, most of the models in the research are oversimplified. Therefore, this research aims to develop a method to optimise FMS production considering the overall system, by having access to an FMS industrial implementation. This research contributes to knowledge in four main areas, namely, (1) the interactions of FMS production problems have been investigated, (2) a framework has been developed to integrate the simulation and optimisation for FMS to enable optimisation algorithms working with DES models effectively, (3) a comprehensive FMS simulation model has been built and validated on the industrial shop floor and (4) multi-objective optimisation has been applied to the FMS scheduling problem, considering interactions with other problems. Based on the results and limitations of this research, real-time simulation, mock-up FMS and improve computational efficiency are suggested for future work.PhD in Manufacturin

Support for operational production planning and resource management in small and medium-sized enterprises

У оквиру ове докторске дисертације истражена је подршка процесу оперативног планирања производње и управљања ресурсима у малим и средњим предузећима. Посебан фокус стављен је на активности распоређивања и терминирања, који чине најкомплексније планерске проблеме на оперативном нивоу. Мала и средња предузећа (МСП) представљају доминантну категорију предузећа у Републици Србији, а и шире у земљама Европске уније (ЕУ-28). МСП представљају најучесталију категорију и у производном сектору Републике Србије и ЕУ. Производња према поруџбини и жељама купаца и процесна организација производње представљају најзаступљенији облик производње у МСП, а Job Shop проблем распоређивања је саставни део процеса оперативног тј. краткорочног планирања производње у овој врсти предузећа. Имајући у виду да оперативно планирање непосредно претходи активностима трансформације предмета рада и стварању додатне вредности, посебан нагласак дат је на управљању производним ресурсима у процесу производње (сировине, материјали и други предмети рада, машине, алати и остала средства за рад, људски ресурси, време према коме се активности планирања реализују, новац тј. капитал, информације, тржиште). У дисертацији се даје преглед основних теоријских појмова: мала и средња предузећа, подршка МСП, процес управљања у МСП, планирање производње и управљање ресурсима. Поред тога, посебно је дефинисан процес оперативног планирања производње, са аспекта активности из којих се састоји. Распоређивање и терминирање у производњи су препознати као једни од најчешћих проблема из домена оперативног планирања производње. Они подразумевају распоређивање производа на машине, тј. проналажење редоследа радних задатака или послова који треба да се изврше на свакој од више машина. Поред тога обухватају и дефинисање временских термина за почетак и завршетак појединих производних активности. Циљ прављења адекватног распореда, тј. редоследа операција, произилази из ограничења капацитета производних ресурса (радници, машине и друга производна опрема).This dissertation proposal explores the support for operational production planning in small and medium-sized enterprises (SME). Special emphasis is put on scheduling activities that represent the most complex planning problem at the operational level. SMEs are the predominant category of enterprises both in Serbia and in the European Union (EU-28). SMEs also present the most frequent type of enterprises in the manufacturing sector in Serbia and the EU-28 countries. Make-to- Order (MTO) production and production organization according to the process are the most common forms of production in small and medium-sized manufacturing enterprises, and the Job Shop scheduling problem is an integral part of operational, i.e. short-term production planning in this group of enterprises. Bearing in mind that operational production planning is directly and closely related to the transformation of raw materials and semi-manufactured goods, which creates and adds value, we emphasize the need to manage manufacturing resources adequately in the production process (materials, machines, tools, labour force, time, money - i.e. capital, information, market). The dissertation proposal presents the overview of basic theoretical concepts: small and medium-sized enterprises, support for SMEs, the process of management in SMEs, production planning, and resource management. Additionally, the process of operational production planning is defined from the aspect of activities it encompasses. Production scheduling problems are observed as one of the most frequent issues in the field of operational production planning. They include scheduling products to machines, i.e. finding the sequence of tasks and activities that need to be performed on each of available machines. Also, it includes determination of time slots for the beginning and completion of certain manufacturing activities. The aim of an adequate schedule, i.e. sequence of operations, arises from the capacity constraints of production resources (workers, machines and other production equipment). Therefore, special attention is dedicated to the improvement of scheduling activities, to make adequate operational planning process which is harmonised with the needs of a particular enterprise