جستجوی مقالات مرتبط با کلیدواژه « سرعت اسکن » در نشریات گروه « مکانیک »

Selective laser melting (SLM) is a laser powder-bed fusion method that offers great potentials in producing components with complex shapes and geometries. Process parameters like laser power and scan speed have significant effect on the induced temperature gradient which determines the molten pool dimensions and surface integrity. Due to the transient feature and fine dimensions of the molten pool, monitoring and measuring the induced temperature gradient and the pool dimensions are extremely challenging. In this article, a finite element model has been used to analyze the process and investigate the scanning speed and laser power parameters during the SLM process on a substrate of Ti6Al4V alloy. In this study, first the theoretical equations of laser have been investigated and after modeling, the accuracy of the modeled laser has been compared with the experimental model. After verifying the laser modeling, the FEM analysis of SLM has been carried out for various laser powers and scan speeds to study the effects of the mentioned process parameters. For the modelling, various physics assumptions have been simultaneously used in the software including heat transfer, solid to liquid phase changes equations, surface tension (Marangoni effect), and laminar fluid flow (Navier-Stokes equation) along with the gravity effect. Molten pool dimensions, temperature gradient along the laser moving heat source, width, and depth of the molten pool, as well as the occurrence of the balling effect phenomenon, have been studied separately in each case. The results obtained by FEM analysis have been compared with the experimental model, showing good compatibility.

Bilayer clad sheets normally consist of two or more dissimilar metals of different thickness bonded together. Clad sheets are of great interest in different industries while having the advantages of all base metals. In this research¡ laser forming of Cu-stainless steel (SS) clad sheet is experimentally studied. This composite can be used in microelectronics industry while having the anti-corrosion and strength capability of stainless steel¡ and electrical superiority of copper. The specimens are bent using Ytterbium fiber laser irradiated on a straight path along the sheet width. The effects of main forming parameters including the number of passes¡ scanning velocity¡ beam diameter and laser power are discussed on bilayer sheet¡ and compared with its constituent steel and copper layers. It is found that the thin copper mid-layer strongly affects the rate of bending per pass due to its high thermal conductivity. It was concluded that the increase of laser power increases the bending angle¡ and increase of scanning velocity and beam diameter decreases the bending angle.