Journal of Modern Processes in Manufacturing and Production
Volume:3 Issue: 1, Winter 2014

Different manufacturing enterprises use regularly scheduling algorithms in order to help meeting demands over time and reducing operational costs. Nowadays, for a better useofresources and manufacturingin accordance withcustomer needs and given the level ofcompetitionbetweencompanies, employing asuitablescheduling programhasa double importance. Conventional productionmethods are constantly substituted with new ones for improving the efficiency and effectiveness of the entire production system. In this paper, two Meta-heuristic algorithms, Genetic and simulated annealing, have been used in order to solve the group scheduling problem of jobs in a single stage No-wait flow shop environment in which setup times are sequence dependent,. The purpose of solving the proposed problem is to minimize the maximum time needed to complete the jobs (Makespan). The results show that Genetic algorithm is efficient in problems with small and large dimensions, with respect to time parameter of problem solving.

In this article, the effect of parameters like working gap, work piece rotational speed and material removal mechanism(injection of the SiC Abrasive slurry and Al2O3, use of diamond paste as abrasive tool) in Magnetic Abrasive Finishing process using designing of experiments on the external surface of Cylindrical work pieces of Stainless steel AISI 440C to get minimum surface roughness has been investigated. For implementation of tests, a mechanism was designed and after carrying out the tests, the obtained data was analyzed using Minitab software. Using response surface method the predicted model, the value of surface roughness was represented. Input parameters to produce optimum have also been reached using the predicted model and desirable surface roughness. Also, results show that the surface roughness has been improved by 50% with the working gap of 2 mm and work piece rotational speed of 355 rpm and using diamond paste.

A high strength nickel chromium alloy (50Cr-50Ni-Nb alloy), commonly referred to as IN-657, is specifically used for components in furnaces which are fired by low grade fuel oils containing high levels of vanadium, sodium and sulphur. The purpose of this study is to experimentally investigatethe effect of machining parameters on machinability in turning of Inconel 657. The considered parameters were cutting speed, feed and tool material. Cutting force components, tool flank wear and surface roughness were measuredbased on design of experiments, and then analysis of variance was performed.Experimental results show that tool wear of CBN tools is 50 %lower than that of carbide tools. The Tool material with percentage contribution of 48% and 56% is the main parameter that influencesthe cutting forces and the flank wear, respectively. Also, the cutting speed with percentage contribution of 48% is the main parameter that effects the surface roughness. The lowest surface roughness is attained by the cutting speed of 250 m/min and the feed of 0.05 mm/rev by the CBN tool.

Electromagnetic forming is a high energy rate forming process in which an electromagnetic Lorentz body force is used for deformation of products. In this article, electromagnetic forming process was simulated for the assembly of parts as an innovative method. The effect of important process parameters such as discharge energy, radius and width of rectangular groove on the strength of the assembled products were studied by using finite element technique and design of experiment. After introducing the governing equations, the output of these equations were applied in simulation as a pressure on work-piece. In this simulation, an ax symmetric model was used in analysis and Johnson-Cook theory was applied due to high strain rate to show the plastic behavior of the materials. Finally, the numerical results were compared with the experimental ones reported by other researchers and a good correlation was found between them. Results revealed that the bead depth increases with the increase of the discharge energy and more filling groove, increasing strength of joint. Also Strength of joint increases due to the creation of partial shearing of the tube at the groove edge and interference stresses at the tube and mandrel interface.

Wear is a complicated phenomenon caused by the relative movement of two contacting surfaces compressed together by a normal force. Prediction of the wear, in most cases, requires various experiments and microstructural characterization of the contacting surfaces. Mathematical models based on physical concepts could provide considerable help in understanding the physical behavior and hence the prediction of this phenomenon. Considering the importance of the generated heat in wear, it seems that thermodynamic parameters are suitable measures for wear modeling proposals. One of these thermodynamic parameters is entropy, the rate of generation of which is mathematically modeled for the sliding wear in this work. For this purpose, experimental wear data from two different materials, namely, Steel 4140 and 70-30 Brass were also considered. The results showed a direct relation between the wear depth of 70-30 Brass and the generated entropy. Moreover, a linear relationship was observed between a number of parameter pairs such as 70-30 Brass temperature – rate of entropy generation, wear depth – transferred heat to 70-30 Brass, wear depth – dissipated energy, and rate of entropy generation – dissipated energy. The wear rate also showed a linear relationship with the 70-30 Brass temperature and the rate of entropy generation. The linearity of the “wear depth – rate of entropy generation” suggests the rate of entropy generation as a decent criterion for the prediction and design of the tribo-systems.

Production planning is performed through diverse methods according to the type of the system it is structured upon. One of the most important steps before production planning is to determine which system best fits the firm, and how the facilities should be designed. Both job-shop and group-technology systems have their own pros and cons, each of which is suitable to a specific kind of factory. On the other hand, performance measurement is also important in terms of both productivity and queue factors. A good method to measure the performance is computer simulation by soft wares such as ARENA. This paper utilizes the software for separately simulating both the job-shop and group-technology systems for specific firm, and then compares the results. The results show that the group-technology system is better than the job-shop system in both productivity and queue factors, and it is highly recommended that the system should be changed.