The assimilation process must take place in the shortest possible time and with the lowest costs. These desires are achievable through the most efficient procedures. The paper proposes a procedure ...for managing the assimilation process of a new product, based on the critical path method. The procedure is intended for a company producing plastic products. In the first phase there was a critical analysis of the existing procedure for assimilating a new product. In the following the study presents how the activities carried out for the assimilation of a new product were organized into a project. To implement this project it was used the Microsoft Project software. This is a tool that allows project management to use the critical path method. By applying this method, it can identify the critical activities within the project. In order to minimize the execution time of the project, the execution time of the critical activities must be reduced. The duration of an activity can be reduced by allocating additional resources. Using the Microsoft Project software in the analyzed case, provides to decision makers information that allows them to make decisions that will reduce the duration of the assimilation process of a new product.
In this paper we propose an approach of modeling and simulation of a manufacturing process based on timed colored Petri nets, by developing an application based on XML (eXtensible Markup Language) ...technology. The architecture of an XML file that characterizes a Petri nets includes specific attributes for positions, transitions, arcs and variable declarations and color sets. This makes it possible to modify the model from a structural point of view very easily by adding lines of code for the required colors, positions, transitions and arcs. In order to generate the default model and to customize the XML-type structure, an application was created where characteristic parameters of the manufacturing process will be introduced as well as the values of the program entry. The manufacturing system considered is the realization of the sunroof component within a company. During the simulation process, the working time will be considered as 8 hours. When product demands change, the simulated model can be modified very quickly to perform the analysis according to the new requirements. The arrangement of the entities of the production system can be reconfigured, the production process can be adjusted and the resources reallocated according to the simulation results.
The paper presents the results of research on the use of hierarchical models with colored Petri nets in the evaluation of automated systems for the preparation and analysis of metallographic ...specimens. Modeling with hierarchical colored Petri nets was used to evaluate the performance of a preparation and analysis robotic system for metallographic samples. The automated system is composed of three subsystems: the subsystem for the preparation of metallographic samples, the subsystem for the attack with reagent of metallographic samples, the subsystem for the analysis of metallographic samples. Two models were made: a model with colored Petri nets with simple colors and a model with timed colored Petri nets with complex colors. Each model was developed on two hierarchical levels. Level 1 contains the model of the entire flexible system for the preparation and analysis of metallographic samples. Level 2 consists of three sub-models: the sub-model of the system for the preparation of metallographic samples, the sub-model of the system for the reagent attack of metallographic samples, the sub-model of the system for the analysis of metallographic samples. Models with timed colored Petri nets allow the evaluation of system performance in terms of the number of samples analyzed in a time interval. The performance of the modeled system was evaluated by simulation, considering a time interval of eight hours.
FLiNaK (LiF-NaF-KF: 46·5-11·5-42 mol.-%) is a promising candidate as high temperature coolant for next generation nuclear reactor coolants. Major technical challenge in implementation is the ...selection of structural material that can withstand corrosive nature of FLiNaK. Corrosion study of different alloys such as SS-316L, SS-317L, Inconel-625, Incoloy-800H, Hastelloy-B and Ni-201 was performed in FLiNaK salt. The tests were carried out in the temperature range of 650-850°C in graphite crucibles for 60 h under inert atmosphere. Weight loss of the alloy sample due to corrosion was measured, and corrosion rate was estimated. The salt composition after corrosion was analysed by inductively coupled plasma spectroscopy coupled with atomic emission spectroscopy. The surface morphology of the alloy samples was analysed by scanning electron microscopy. Ni-201 and Hastelloy-B showed better resistance to corrosion than other alloys. Corrosion rate was found to increase with increase in Cr content in the alloy.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The paper presents the results of the research in the field of manufacturing process management through modeling and simulation. The research object is the manufacturing process that is specific to ...the serial production, more specifically refers to the gas cooker manufacturing within a company in Oradea. For modeling and simulation, two methods were used: modeling with timed Petri nets and with queues. Models with Petri nets have been developed gradually. In a first variant, for each operation was considered a single workstation, the operation being modeled by a timed transition whose timing was equal to the time of execution of the operation. The second Petri model was designed to remove these bottlenecks. After removing the bottlenecks, the next level of development was to model the stock of parts and subassemblies associated with each workstation. In the fourth variant with the Petri nets, the supply sequences of parts and subassemblies were also defined. The modeling with queues has made possible to highlight the bottlenecks and occupancy rate of each workstation. Also, a model has been developed in which the execution times of the operations are considered randomly.
Improving the performance of manufacturing systems is the objective of management activities. The paper presents how this objective can be achieved by modeling and simulation. Base on the ...manufacturing process of the part support bush it is modeled the production line. Modeling is done using the TECNOMATIX PLANT SIMULATION program. Using the first model, by simulation, it was found that the resulting production after eight hours was relatively reduced: 28 pieces. Under these conditions, an additional welding post was introduced in the second model. It results in double the production and also in narrow places. The third model is designed in such a way that bottleneck is eliminated, and there is also an increase in production.
Modern manufacturing systems are characterized by the fact that they integrate various machines and work equipment, industrial handling robots, industrial robots performing technological operations ...(welding, riveting, painting, etc.), transfer systems (conveyors, conveyor belts, automated guided vehicle -AGV), storage systems and inspection stations. The paper presents the way in which the assembly project management of a suspended conveyor system was carried out. Critical path method was used. It has identified the assembly operations, the way they succeed in the technological process of assembly, the duration of the operations and the resources (labor force) necessary for their realization. This information has been processed through Microsoft Project resulting in critical activities (critical path), project duration, the ratio between the available and necessary resources (in the analyzed case a significant deficit of the machinist resource) and the corresponding costs. In order to solve the problem of resource requirements, two solutions were used: leveling resources and supplementing them in order to reduce the duration of critical activities. Finally, a version of the conveyor assembly project management resulted in a balance between costs and duration.
This paper presents the results of the research about the automation of the metallographic samples preparation and analysis processes. At the University of Oradea the authors designed and made an ...automated metallographic samples preparation and analysis system. This automated system can achieve polishing, attack by reagents and metallographic analysis. The flexible cell (the automated system) is made of two subsystems. The first subsystem, which is served by an industrial robot, performs the polishing and the sample surface assessment. The second subsystem, also served by an industrial robot, performs the reagent attack and finishes the metallographic analysis in order to determine the microstructure of the sample. The authors have designed a timed Petri nets model in order to assess the performance of the automated system and to identify the possible bottlenecks. The model is made for the case that the system is required to analyse two kinds of samples. The sequences performed by the industrial robots are modelled by transitions with associated timings that are equal to the real time periods taken by the robots to execute the corresponding actions. Other activities, such as grinding polishing, finishing polishing, reagent attack, washing, microscope examining, have been also modelled by means of transitions. The execution of a transition (the completion of a real sequence) is possible if certain conditions are met. These conditions are modelled into the Petri net by means of positions. The number of samples that can be analyzed in a certain time period can be determined by simulation.
Assembly project management of a suspended conveyor Blaga, F S; Stănășel, I; Pop, A ...
ANNALS OF THE ORADEA UNIVERSITY. Fascicle of Management and Technological Engineering,
07/2019, Letnik:
XXIX (XIX), 2019/1, Številka:
1
Journal Article
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