| The shipbuilding industry is of extremely high industrial importance.As its basic equipment and facilities,the ship supporting parts industry has played an important supporting role.Among them,marine diesel engines,as the "heart" that provides power for ship propulsion devices,occupy an important role in manufacturing and production status.Under the order-oriented "multi-variety,small-batch" production mode,the process route conversion is complicated.The heat treatment process is an important process to ensure the performance of parts in production and a key process that affects the production schedule of the entire set of parts.Due to its time-consuming and energyconsuming Large,has become a bottleneck restricting production.How to achieve rapid production and reduce energy consumption at the same time has become a core problem that this type of enterprise urgently needs to solve,and it is also the key to reducing costs and increasing efficiency and improving industry competitiveness.Based on a domestic manufacturer of supporting parts for marine diesel engines,this paper studies the job shop scheduling problem of multiple batches of heat treatment process.Taking the production energy consumption and manufacturing time as the optimization goals,focusing on the batching and scheduling links in the heat treatment process,considering the volume difference and dynamic reachability of the workpiece tasks,the research is carried out from the aspects of scheduling mechanism,optimization model,optimization algorithm,etc.:First of all,through on-site visits to the company to understand the production status of the heat treatment workshop and summarize the existing problems of the company.On this basis,a time-and space-based heat treatment job shop scheduling problem is established,which is divided into two stages: space-based static scheduling and timebased dynamic scheduling.There are four levels of content in each stage: Assumptions,mathematical models,batching and scheduling,and solutions are explained in detail,and the relationship between each stage and each level is summarized.Secondly,considering the simultaneous arrival of the workpiece in the heat treatment workshop and the uncertainty of the arrival time of the workpiece in the subsequent heat treatment process,a "pre-post" heat treatment workshop scheduling mechanism is proposed to solve the problem of Job Shop Scheduling with Multiple Batches Loading(JSSMBL).The early stage mainly solves the static scheduling problem of the workpieces arriving at the heat treatment workshop at the same time;the latter mainly solves the scheduling problem of the dynamic arrival of the workpieces caused by the uncertainty of the arrival time of the workpieces in the heat treatment process.The relationship between the volume of the workpiece,the volume of the batch,the volume of the heat treatment furnace and the three are studied,and the JSSMBL model based on volume group batching is established.The SDVJS-VMA heuristic algorithm based on volume group batching is designed in the early stage,and the BV-LAB algorithm based on event-triggered and improved forward-looking batch LAB strategy is designed in the later stage.Focusing on the volume relationship factor,and the SVBL heuristic algorithm combining the two is used to solve the model of reducing the volume deviation rate and increasing the batch loading rate.The superiority of the algorithm is verified by calculation examples and comparison with other algorithms.Thirdly,considering the dynamic arrival of the workpiece in the heat treatment workshop,with the minimum completion time as the optimization goal,a JSSMBL problem model with arrival time is established.The model is optimized for batching based on the arrival time of the workpiece,which can use the heat treatment furnace more efficiently,thereby reducing the energy consumption and cost of heat treatment.An improved genetic algorithm is designed to solve the model and generate an optimal scheduling plan.The coding rules based on stages and procedures and new crossover and mutation operators are designed to enable the algorithm to solve the model better and improve the local search capability of the algorithm.The superiority of the algorithm is verified by calculation examples and comparison with other algorithms.Finally,based on the two proposed optimization algorithms,combined with the actual production in the heat treatment workshop of marine diesel engine parts,the configurable MES studied by our research group is redesigned and the heat treatment of marine diesel engine parts and components including the heat treatment scheduling function module is developed.The management system has achieved good results. |
