Florin Blaga

CONSIDERATION ON FLEXIBLE MANUFACTURING CELL MODELING WITH TIMED COLOURED PETRI NETS

This paper presents how color Petri nets can be used in flexible manufacturing system models.. It is studied the cell from the Faculty of Engineering Management and Technology. In this cell process four parts: two pieces of revolution and two prismatic parts. In a first variant coloured Petri nets model is made without taking into account the time factor. This does not allow a prioritization of processing and the evaluation of manufacturing cycle time. If we consider the factor of time, coloured Petri nets model allows prioritization processing by the fact that each color is associated with a part it can be attach timing. May also be taken into account the processing times through timings associated with the transitions.

Decision Based Modeling of a Flexible Manufacturing Cell based on Hierarchical Timed Colored Petri Nets

Abstract The design techniques of flexible manufacturing systems deal, among other methods, with the application of high level Petri Nets. The modeling and simulation of a flexible manufacturing cell (FMC) can be done by implementing hierarchical techniques based on Colored Timed Petri Nets. This paper is focused on implementing decisions and strategies in a flexible manufacturing cell with colored and hierarchical techniques. In this context we discuss the decision making for machine, parts and allocated tools in transitions. The FMC model is designed based on the cell operating at the laboratory of the Faculty of Managerial and Technological Engineering, University of Oradea. In this article, we explain the design techniques using color and hierarchy to evaluate the overall performance of the cell based on part arrival decisions and part processing decisions in transitions of each sub-model of the cell.

COLORED PETRI NET USED TO MODEL FLEXIBLE MANUFACTURING CELL

This paper focused on the modeling of Flexible Manufacturing Cell (FMC) using colored Petri nets without time. Using colored Petri nets, it is possible to structure of manufacturing system organization, material and data flows, concurrency and synchronization of the process and machining operation of the system. Model is constructing using CPN (colored petri net) Tools to find the connection between the place, transition and arcs of the system. For this model, we studied the FMC from the faculty of engineering Management and Technology, University of Oradea. Here we are processing two different parts: two parts for milling and two parts for turning in this FMC. Here we also discussed the modeling of the same system with two different FMC model and features of the system. Keywords—Flexible manufacturing cell, colored Petri net, modeling, simulation and comparison.

Parametric Design of Gear Hob Cutter

The gears are some of the most used mechanical transmission due to the advantages its provide: constant transmission ratio, high power transmitted, high efficiency, small size, silent operation, precision kinematic, etc. This causes the wheel to be one of the most valuable machine elements both in terms of accuracy and processing technology as well. From the technological point of view due to high precision and productivity, one of the most methods used is processing with gear hob cutter. Although the tool profile does not depend on the number of teeth on the wheel, but only its module, large diversity of gear requires the design of gear hob cutters tailored to existing needs. As it is known the gear hob cutters are complicated and expensive gear cutting tools, both due to the manufacturing process and in terms of design, requiring a significant amount of calculations, high effort from the designer and consequently results in a large cycle of design. For this reason, the literature and in various websites, there are many studies and research information to optimize the design process and increase accuracy of gear hob cutters.

Experimental Researches Concerning Evaluation of Mechanical Vibrations of Five Axes Machining Center Equipped with Rotary Tilting Table

Precision of the machining centers is influenced by many factors among which are mechanical vibrations that occur in the machine-tool-part-device system. Evaluation of vibration level for five axes machining centers is a very important issue considering structural and functional complexity of these equipments. The paper presents researches performed at University of Oradea to evaluate vibration of TMA-AL 550 five axes machining center, equipped with a two rotating axes table, during the machining process. There have been used two methods: evaluation of the dynamic behavior of the spindle using a laser vibrometer and evaluation of mechanical vibrations of the five axes machining center using triaxial accelerometers. Measurement data had been processed using spectral analysis and time-frequency parameters, revealing frequency domains which can cause high amplitudes of vibration. Results also show that the measured vibration levels are not exceeding the accepted limits.

EVALUATION OF THE TEXTILE INDUSTRY FABRICATION LINES PERFORMANCES USING PETRI NETWORKS MODELS

The paper presents an approach to the matters of the flux lines which are specific to the industry of textile clothes, from the point of view of their balance. Frequently, it happens that the time periods of the operations are much different, and this leads to jams and extended waiting times, with negative influence on the efficiency. This paper proposes the use of a modeling and simulation method based on timed Petri networks, which will allow the analysis of the flux lines operation, the highlighting of the bottlenecks and to yield information to the personnel that take managerial decisions. Three lines, which manufacture the following products: jacket, skirt and trousers, are analyzed. For each case, the modeling and simulation procedure yields solutions for jam solving.

Evaluation models for the noise diminution due to the phonique barrier walls

The present paper contains our study regarding the diminution of the urban noise using the phonique barrier walls conformed to the EMPARA procedure, which is based on the simplified of the standard method for the measurements and computes of the surface traffic inside the urban agglomeration, as they are given in SRM2 laws (Netherlands standards). There are made the studies taking into account all the parameters that characterize the the noise and they are graphical representations having the “n‐1” constant parameters and only one having the time variation law. In this way we are obtained the influence of each parameter in the diminution of the urban noise using the phonique barrier walls. In addition we realized a measurement for a real barrier wall inside the Oradea town. The comparison between them was enough good, that means our theoretical study is correct and characterizes the noise pollution and its diminution on the urban agglomeration. The measurement device was a CENTER 322 Sound Lever Meter. Th...