Journal of Modern Processes in Manufacturing and Production
Volume:2 Issue: 2, 2013

Optimization of process parameter is one of the ideal goals in laser sintering. The results of this process were measured as output parameters like: density, micro hardening, macro hardening, tension, roughness, stiffness, balling. In this paper, the influence of input parameter such as laser power, scan speed, material powder and etc are surveyed on output parameter like balling affection and the thickness of a layer. Iron and copper powder were used in this experiment in order to produce a full density single layer on 5 mm depth bed powder. One of the efficient factors on this process is overlapping which has a reverse impact on the high and low pulse power. Finally a coupon was produced with the best setting.

Nowadays, tube bonding in vehicles structure is noticeably considered by many researches. In this paper, local tube compression process by a rubber ring has been studied. Firstly, simulation of the process was performed by FEM. Then, experimental test has been carried out to validate the numerical results. Numerical and experimental results were compared showing a good agreement. In the second part of this study, tube assembling of a two tubes was examined by a rubber ring. The simulation results have presented including stress distribution of both tubes. Finally, this method was compared with other tube assembling methods by observation of tube profile deformation.

The map and the model designed by a designer and presented to a manufacturer in the form of a map is the result of his knowledge and innovation. The manufacturer, in turn, uses his best effort to produce a part accordingly. However, because of production problems and raw material, producing a precise part is very difficult and costly. One of the most important problems in this regard is designing the production process and tolerances for each stage in order to determine the final tolerance for the part. The solution to this problem lies in deciding on the priority of stages of operation and using tolerance chart. Selecting stages of machining and effective parameters like the depth of machining is important. Each stage of machining has its own tolerance, and in the end, when all tolerances are added up, the final tolerance might be more than the permitted assigned tolerance on the map. To prevent cumulative tolerance and reduce the production waste, it is necessary to decide on the tolerances for each stage (tolerance chart). Using software systems for this purpose not only increases speed and precision significantly but also reduces expenses to a large extent. A software has been designed for determing stages of machining and permitted tolerance for each operation (tolerance chart), and its efficiency is demonstrated in this article by using an example.

Due to the massive loss of leaves in parks and green spaces and big cities such as Isfahan and the lack of domestic production of leaf vacuum shredder machine for use in large green spaces of parks, the design and construction of the collecting and recycling by the system is need so the design of the vaccum section which is one of the main parts and includes entrance, channels and ducts and exhaust air passage, a centrifugal fan were diseigned according to the working conditions of the device and and based on the fluid mechanics. Also vaccum air flow rate test was done in this research.

High speed wind tunnels are widely used in the study of fluid flow behavior around various objects. The air flow in the starting step of supersonic wind tunnels is transient including strong shock waves caused by the interaction of the tunnel main stream and the boundary layer at walls. To arrive in running step, the tunnel must be designed so as these waves leave immediately the test section. Otherwise, they will hinder the air flow through the tunnel. Accordingly, as a clear practical fact, the tunnels unable to pass the starting step are considered as unusable.In this paper, a 3-D computational fluid dynamic analysis of the starting stage of a supersonic wind tunnel with a target Mach number of 3 is performed. The results obtained in this work are in agreement with the expected physical behavior of the flow field and can be applied as the designcriterion of the high speed wind tunnels.

Medical staples are one of the nitinol shape memory alloys applications which their pedicles have to be bent for suitable function with an appropriate angle at a specifiedtemperature. It is achievable by shape memory effect. For this purpose, samples of nitinol super elastic alloys were bent in a steel mold with different angles & formed orthopedic staples. Then shape memory effect was induced in all samples under aging process. In this research effect of heat generated in the shape memory alloys specimens due to electrical current was investigated. Phase transformation temperatures of samples were measured by differential scanning calorimetry (DSC) technique. Results showed that smaller bending angel results in lower amount and duration of current for shape recovery. Strain increased in them in the same amount of current. Results of this study can improve manufacturing of NiTi medical staples.