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Open Access Article
1 - Solving the Problem of Scheduling Unrelated Parallel Machines with Limited Access to Jobs
Mohammadreza Naghibi Abolfazl AdressiNowadays, by successful application of on time production concept in other concepts like production management and storage, the need to complete the processing of jobs in their delivery time is considered a key issue in industrial environments. Unrelated parallel machin MoreNowadays, by successful application of on time production concept in other concepts like production management and storage, the need to complete the processing of jobs in their delivery time is considered a key issue in industrial environments. Unrelated parallel machines scheduling is a general mood of classic problems of parallel machines. In some of the applications of unrelated parallel machines scheduling, when machines have different technological levels and are not necessarily able to process each one of the existing jobs in the group of jobs and in many of the industrial environments, a sequence dependent setup time takes place during exchanging jobs on the machines. In this research, the unrelated parallel machines scheduling problem has been studied considering the limitations of sequence dependent setup time of processing of jobs and limited accessibility to machines and jobs with the purpose of minimizing the total weighting lateness and earliness times. An integer scheduling model is proposed for this problem. Also, a meta-heuristically combined method consisting of Genetic algorithm and Particle swarm optimization (PSO) algorithm for its solutions is proposed. The obtained results of the proposed algorithm show that the proposed algorithm is very efficient especially in problems with large dimensions. Manuscript profile -
Open Access Article
2 - Micro Machining of AISI 440C Stainless Steel using Magnetic Field and Magnetic Abrasive Particles
Yahya Choopani Mohammad Reza RazfarMagnetic abrasive finishing (MAF) is a micromachining process that uses magnetic field and magnetic abrasive particles to conduct the mechanism of material removal in micro-nanometer scales. In this paper, by an experimental method and statistical analysis, the effects MoreMagnetic abrasive finishing (MAF) is a micromachining process that uses magnetic field and magnetic abrasive particles to conduct the mechanism of material removal in micro-nanometer scales. In this paper, by an experimental method and statistical analysis, the effects of parameters like working gap, work-piece rotational speed and material removal mechanism (injection of abrasive slurry of Al2O3) in the MAF process, on the external surfaces of cylindrical pieces of stainless steel (AISI 440C)were investigated on surface roughness. To do the experiments, a mechanism was designed and constructed. The results of this research show that the working gap and work-piece rotational speedhave a significant effect on the improvement of the surface roughness. It has been indicated that in vitro surface roughness improved 20% as a result of the gap working of 2 mm, workpiece rotational speed of 355 rpm, using the injection of abrasive slurry of Al2O3. Manuscript profile -
Open Access Article
3 - Using Experimental Procedure to Improve the Efficiency of the Two Stand Reversing Cold Mill
Mohammad Heydari ViniProduction of thin steel strips with 0.18-0.26 mm thickness is about 0.75 of annual production of the two stand reversing cold mill, while its efficiency is 60%. This is due to the fact that after montaging the grinded work rolls, rolling thin steel strips (with thickne MoreProduction of thin steel strips with 0.18-0.26 mm thickness is about 0.75 of annual production of the two stand reversing cold mill, while its efficiency is 60%. This is due to the fact that after montaging the grinded work rolls, rolling thin steel strips (with thicknesses less than 0.18 millimeters) is unavailable. Initially, unsuitable surface roughness, the friction between rolls and the strip and thermal conditions result in the rupturing of steel strips. Usually, cold rolling of several coils of thick steel strips, for example 0.3 -0.5 mm thickness, for the first rolling pass is necessary. This primary preparation reduces the work rolls life and produces unneeded coils. In this study, by experimental investigation, the effective parameters such as lubrication condition, surface roughness of work rolls and their improvement, the possibility of cold thin steel strip rolling is examined. Finally, several methods for improvement the cold rolling efficiency and decreasing the amount of strip rapture in the two stand reversing cold mill are presented. Manuscript profile -
Open Access Article
4 - Predicting Failure in the Hydraulic Lift Structures with Monitoring and Fuzzy Logic
Morteza Jamshidian Sayed Ali MousaviThere are several strategies for maintenance and repairing of devices in industry. However, they are still confronted with many uncertainties. A hydraulic lifting device after ten years of working in a technical center in Isfahan is faced with uncertainty in terms of re MoreThere are several strategies for maintenance and repairing of devices in industry. However, they are still confronted with many uncertainties. A hydraulic lifting device after ten years of working in a technical center in Isfahan is faced with uncertainty in terms of reliability. Being able to know the reliability of pieces means predicting failure occurrences, which is accomplished by condition monitoring of the pieces by measurement of errors and ambiguous boundaries. Using condition monitoring and expert groups and multiple membership functions by creating a fuzzy system in MATLAB software uncertainties important components and the structure status are obtained in the fuzzy form. Moreover, between the healthy and damaged conditions a percentage of health is obtained and the health of system is shown. Manuscript profile -
Open Access Article
5 - Design and Construction of Load Cell of a Three Point Hitch Dynamometer for Tractor John Deere 3140
Mohsen Beigi Mohammad Ali Ghazavi Iman AhmadiMeasurement of the values of forces in tractor arms is of great importance due to draft of agricultural equipment. These values can be used for testing and evaluation of the agricultural machinery, selection of suitable tractor, etc. The tools which are used for measure MoreMeasurement of the values of forces in tractor arms is of great importance due to draft of agricultural equipment. These values can be used for testing and evaluation of the agricultural machinery, selection of suitable tractor, etc. The tools which are used for measurement of the forces are called dynamometer. The main objective of the present study was to design and evaluate a load cell for integral three point hitch John Deere 3140 tractor. These load cells are installed on the bottom links and measured draft forces. The sensitive parts of these load cells are square side pins on which some strain gages were installed and the force was measured. This load cells do not have the errors usually faced with in other load cells such as reciprocal sensitivity and hitch point movement. Besides, their manufacturing cost is very lower than the other similar load cells. Manuscript profile -
Open Access Article
6 - Development of Design and Manufacturing Support Tool for Optimization of Ultrasonic Machining (USM) and Rotary USM
Morteza Sadeghamalnik Mohammad Rasoul NajafiUltrasonic machining (USM) is a mechanical material removal process used to erode holes and cavities in hard or brittle work pieces by using shaped tools, high-frequency and an abrasive slurry. This paper addresses the concept and development of an expert system (ES) fo MoreUltrasonic machining (USM) is a mechanical material removal process used to erode holes and cavities in hard or brittle work pieces by using shaped tools, high-frequency and an abrasive slurry. This paper addresses the concept and development of an expert system (ES) for hard and brittle material, such as glass, quartz, diamond, carbides, semi conducting materials, ceramic and graphite which can be manufactured with ultrasonic machine or rotary ultrasonic machining. The expert system is developed based on object oriented technique. The system links with a feature based CAD system in order to extract design data. The expert system is linked with databases. The machining cycle time, cost, penetration rate and productivity, of each selected design feature are estimated. The system provides useful information such as machining cycle time and cost, penetration rate and efficiency of machining of the selected design feature for product designers and manufacturing engineers to select optimum machining parameters. Also the expert system compares ultrasonic machining (USM) and rotary ultrasonic machining (RUSM) for the same design feature in concurrent engineering environment. Manuscript profile
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