A Production Process Object Modeling Method Study Based On Petri Nets In Manufacturing Enterprises

With customer's demand entering the era of diversity and individuality, manufacturing enterprises may face to the challenge of orders random, multi-variety, small batch and production flexible. As an effective production management tools, production process modeling is playing an increasingly important role in production workflow study, production capacity analysis and production online monitor. However, there are several disadvantages in the traditional process modeling, such as modeling process complex, lack of flexible, insensitive for market, more modeling expenditure, low accuracy, as well as the huge workload, etc. These deficiencies have seriously influenced the production management to continuous to improve. Therefore, it is necessary to create a new production process modeling method to set up a manufacturing model conveniently, and the model needs to be visual, modularize and object-oriented.Above all, the traditional production process modeling methods have been analyzed, and a new modeling method is proposed by combining Petri nets and Object-oriented technology, which is called Production Process Object Modeling (PPOM). PPOM focuses on the production capacity of each manufacturing cells. Then, PPOM is defined by Petri Nets. And with the proposed method, the manufacturing modules or producing cells are highly abstracted as several production sub-Places models. In these models, the internal processing statuses are assumed herein. What's more, according to the practical production process flow, the sub-Places are combined and permuted to construct a PPOM abstracted model of production system. Meanwhile, the PPOM objective function model is set up to calculate the manufacturing cells'capacities and find the minimum capacity cell with Simulated Annealing Algorithm. After analyzing the manufacturing cells'capacities, the production bottleneck is detected immediately.Subsequently, the theoretical method is put into a manufacturing enterprise practice. Take Z Transformer Corporation as an example, the power transformer production process is analyzed first, and the power transformer PPOM definition is given with Petri Nets. Third, a PPOM abstract model is built to reflect the power transformer practical process and the model performance is analyzed at the same time. And then a transformer production capacity objective function model is established to detect the capacity bottleneck successfully with Simulated Annealing Algorithm. Furthermore, some measures are taken to improve capacity, decrease production cycle time, raise efficiency and increase benefits. Thus the PPOM method was validated availably.