Simulation of laser structuring by three dimensional heat transfer model (original) (raw)
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The current work examines the heat-and-mass transfer process in the laser multilayered cladding of H13 tool steel powder by numerical modeling and experimental validation. A multiphase transient model is developed to investigate the evolution of the temperature field and flow velocity of the liquid phase in the molten pool. The solid region of the substrate and solidified clad, the liquid region of the melted clad material, and the gas region of the surrounding air are included. In this model, a level-set method is used to track the free surface motion of the molten pool with the powder material feeding and scanning of the laser beam. An enthalpy-porosity approach is applied to deal with the solidification and melting that occurs in the cladding process. Moreover, the laser heat input and heat losses from the forced convection and heat radiation that occurs on the top surface of the deposited layer are incorporated into the source term of the governing equations. The effects of the laser power, scanning speed, and powderfeed rate on the dilution and height of the multilayered clad are investigated based on the numerical model and experimental measurements. The results show that an increase of the laser power and powder feed rate, or a reduction of the scanning speed, can increase the clad height and directly influence the remelted depth of each layer of deposition. The numerical results have a qualitative agreement with the experimental measurements.
International Journal of Industrial Engineering Computations, 2015
Laser direct structuring (LDS) is very important step in the MID process and it is a complex process due to different parameters, which influence on this process and its final product. Therefore, it is very important to use a reliable model to predict, analyze and control the performance of the (LDS) process and the quality of the final product. In this work we develop mathematical models by using Artificial Neural Network (ANN) and Response Surface Methodology (RSM) to study this process. The proposed models are used to study the effect of the LDS parameters on the groove dimensions (width and depth), lap dimensions (groove lap width and height) and finally the heat effective zone (interaction width), which are important to determine the line width/space in the MID products and the metallization profile after the metallization step. We also study the relationship between the LDS parameters and the surface roughness which is very important factor for the adhesion strength of MID structures. Moreover these models capable of finding a set of optimum LDS parameters that provide the required micro-channel dimensions with the best or the suitable surface roughness. A set of experimental tests are carried out to validate the developed ANN and the RSM models. It has been found that the predicted values for the proposal ANN and RSM models were closer to the experimental values, and the overall average absolute percentage errors were 4.02 % and 6.52%, respectively. Finally, it has been found that, the developed ANN model could be used to predict the response of the LDS process more accurately than RSM model.
Procedia Technology
The present work reports two-dimensional simulation of laser cladding process to understand the influence of process parameters on clad geometry formation for better process optimization. The application deals with pure copper powder cladding of SS316L substrate for process feasibility for thicker coating layers by CO 2 laser. For this purpose, first mathematical model is developed and dealt numerically using multi-physics software. Conservation equation of energy, momentum and mass of this process are coupled through the temperature variable and solved to adapt the laser cladding process. The boundary conditions due to the laser melting process of dissimilar materials have to be deal with complex assumptions are applied in mathematical modelling to simplify problem due to the different materials properties. The deformation of free surface is calculated using moving mesh by the way of ALE (Arbitrary Lagrangian and Eulerian) method. In addition, thermo-capillary forces and their effect on fluid flow inside the melt pool are also considered in modelling to complete the process optimization. Thermal and stress distributions due to the process are also evaluated in the developed process simulation. The results provide approximate information about the effect of each selected parameters on clad geometry formation. The influence of process parameters have shown the best choice of optimization.