Parametric Study and Multi-Criteria Optimization in Laser Cladding by a High Power Direct Diode Laser

Abstract

In laser cladding, the performance of the deposited layers subjected to severe working conditions (e.g., wear and high temperature conditions) depends on the mechanical properties, the metallurgical bond to the substrate, and the percentage of dilution. The clad geometry and mechanical characteristics of the deposited layer are influenced greatly by the type of laser used as a heat source and process parameters used. Nowadays, the quality of fabricated coating by laser cladding and the efficiency of this process has improved thanks to the development of high-power diode lasers, with power up to 10 kW. In this study, the laser cladding by a high power direct diode laser (HPDDL) as a new heat source in laser cladding was investigated in detail. The high alloy tool steel material (AISI H13) as feedstock was deposited on mild steel (ASTM A36) by a HPDDL up to 8kW laser and with new design lateral feeding nozzle. The influences of the main process parameters (laser power, powder flow rate, and scanning speed) on the clad-bead geometry (specifically layer height and depth of the heat affected zone), and clad microhardness were studied. Multiple regression analysis was used to develop the analytical models for desired output properties according to input process parameters. The Analysis of Variance was applied to check the accuracy of the developed models. The response surface methodology (RSM) and desirability function were used for multi-criteria optimization of the cladding process. In order to investigate the effect of process parameters on the molten pool evolution, in-situ monitoring was utilized. Finally, the validation results for optimized process conditions show the predicted results were in a good agreement with measured values. The multicriteria optimization makes it possible to acquire an efficient process for a combination of clad geometrical and mechanical characteristics control.Keywords Laser cladding . High power direct diode laser . Response surface methodology (RSM) . Multi-response optimization Lasers Manuf. Mater. Process.

Investigation of Geometric Characteristics in Curved Surface Laser Cladding with Curve Path

“…Analysis of variance (ANOVA) was used to verify and analyze the fitted models. The significance level (α) was set at 0.05, which is a commonly used level in significance tests [9,20,21]. Experimental validation to verify that the optimized processing parameters and substrate size was conducted with targeting on the desired geometric characteristics.…”

“…Farahmand and Kovacevic used response surface methodology embedded with a central composite design module to investigate the influences of laser power, powder flow rate, and scanning speed on the clad height, heat-affected zone height, and clad microhardness. A multiple regression analysis was used to establish the models, and the accuracy of the models was validated by analysis of variance [9]. Laser cladding on curved surfaces has also drawn research attention because of its demand in industrial applications.…”

“…There are numerous studies focusing on the optimization of processing parameters in laser cladding, but their research was primarily concentrated on the analysis and optimization of flat surface laser cladding [7][8][9]. Although research on curved surfaces has been started, primary investigation has focused on circumferential cladding paths [10][11][12][13].…”

Prediction of geometrical characteristics and process parameter optimization of laser deposition AISI 316 steel using fuzzy inference

“…Farahmand and Kovacevic [16] used a predictive approach to assess the influence of input parameters on geometry and microhardness of the deposited beads, established the dependency relationships between the inputs and outputs and optimized the deposition process parameters of AISI H13. They concluded that when increasing the laser scanning speed (mm/s), the bead height and HAZ (heat affected zone) decreased, while microhardness increased.…”

“…They also used CCD/RSM/ANOVA to identify statistical relationships between input parameters and output variables and optimal processing parameters identification. This study used similar approach of previous works (Farahmand and Kovacevic, 2014) but using different powder materials, which could be considered an extended research. They concluded that the powder flow (g/min), the gas flow rate (SCFH) and the interaction between the gas flow rate and the standoff distance (mm) were the most significant factors affecting the bead height (mm), while the laser power (W) was the factor most affected the bead width (mm).…”