جستجوی مقالات مرتبط با کلیدواژه « powder metal laser re » در نشریات گروه « مکانیک »

One of the main goals of researchers in the laser sintering process of metal powders is optimization of process parameters in order to reach the properties of manufactured parts to the raw material properties. In order to produce fully dense multi-layer parts, it is necessary to optimize the process parameters of a mono-layer part. In the present study, experiments have performed on a powder bed with the thickness of 5mm. The fabricated parts have been produced by a single laser scanning of the powder bed. By moving the laser beam on the powder bed, circular pieces with a diameter of 20 mm have been produced. Based on preliminary experiments and according to the input parameters, a function has defined for energy density. Therefore, output parameters have investigated based on weight percent of Cu and energy density. Results show that there is a saddle point in the diagram of the effect of energy density and the weight percent of Cu on output parameters. This point shows the transmission of sintering to complete melting. Optimal condition of manufacturing parts by rapid prototyping is the condition which strength, surface finish and dimensional accuracy are at the highest possible level while shrinkage, balling and thermal stresses are at the lowest possible level. The results show that the best condition is while the energy density sets between 120-140 W/m2 and the weight percent of Cu sets between 18-22 %.

One of the main goals of researchers in metal powders laser sintering¡ is optimization of process parameters in order to close out the main properties of the raw materials have been produced to the piece. For this purpose¡ many experiments have been carried and parameters such as density¡ hardness¡ micro hardness¡ strength¡ surface finish¡ appearance¡ and residual stress have been studied. In this paper the influence of parameters such as laser power¡ scanning speed¡ and powder material and etc. on output parameters such as penetration depth¡ strength¡ balling phenomenon is investigated. In order to produce a multi-layer fully dense parts by the process of pulsed laser¡ to optimize the performance of the laser and material parameters at first¡ it is necessary to single layers is investigated. Experiments carry out on free powder bed depth is 5 mm. Each piece of a single layer on the substrate with once laser scanning powder is produced. Movement of the laser beam on the surface produce a washer with 20mm diameter.