Optimization of the Efficiency of the Laser Metal Deposition Process Applied to High Hardness Coatings by the Analysis of Different Types of Coaxial Nozzles

Abstract

Laser Metal Deposition (LMD) or laser cladding is a technology capable of coating, repairing and manufacturing components by injecting molten metal powder on a substrate. Some of the advantages of this technology are: wide range of materials available in powder, reduced thermal distortion, coatings and repaired parts of high quality. However, the biggest advantage can be its relative ease of implementation in a multiprocess machine tool and subsequent automatization. The supply of hybrid machines in the world market that implements the LMD process is increasing (IBARMIA, DMG MORI, MAZAK, OKUMA, etc...), making the production more flexible in a single machine and introducing this process in more applications and industrial sectors. However, hybridization also presents problems that are difficult to solve. Some of the most noteworthy are those associated with the use of powdered metallic material both from the point of view of the safety and hygiene of the operators and also of the waste management and integrity of the machine itself, being its most serious effects at lower efficiency of the process. In this article, the study of the efficiency of different LMD nozzles is addressed for the coating of a hardened steel using for it the hybrid multiprocess machine IBARMIA ZVH45 /1600 Add + process, with the aim of finding the most efficient and, therefore (the one that generates less waste) and which, in turn, offers good productivity. Keywords: Laser cladding, hybrid manufacturing, LMD, coatings, hardened steel, wear resistance, coaxial nozzle.

Strategy Development for the Manufacturing of Multilayered Structures of Variable Thickness of Ni-Based Alloy 718 by Powder-Fed Directed Energy Deposition

“…This model achieved a high level of accuracy by taking into account purely geometrical parameters, such as the characteristics of the single clad ( Figure 1) and the overlap percentage (d o ) of the coating. On the other hand, the dilution area of the coating can be obtained from the experimental results of previous works [13,27,28]. The model employs the single clad characteristics (h, w, p, and A) as inputs ( Figure 1b) and it assumes that the coating (Figure 2a) is the sum of the clads deposited at the overlap distance.…”

“…This assumption is a simplified constant value of the energy balance between the deposited material and the melted substrate that was studied by Chakraborty et al [29]. It was obtained by analyzing all of the fabricated coatings in previous works with different nozzles, metallic powders, and substrates [13,27,28].…”

“…This assumption is a simplified constant value of the energy balance between the deposited material and the melted substrate that was studied by Chakraborty et al [29]. It was obtained by analyzing all of the fabricated coatings in previous works with different nozzles, metallic powders, and substrates [13,27,28]. The effectiveness of the model was validated with Eutroloy 16606A coated cross sections, analyzed in previous works [13,27], and deposited through a continuous coaxial nozzle with a slit of 1 and 0.5 mm (Figure 5a,b).…”

“…Dilution Depth (p): Units KW, mm•s −1 and g•s −1 ; Equations (24)- (28). C p = 0.0106 × (P) 2 − 0.0609 × P + 0.0323 (27) D p = −0.2778 × (P) 2 + 1.8937 × P − 0.6502 (28) Apart from this, the characteristics of the single clad of Alloy 718 are also dependent upon the tilting angle (α) for material deposition, as previously demonstrated [25], reaching a maximum tilting angle of 30 • .…”

“…Dilution Depth (p): Units KW, mm•s −1 and g•s −1 ; Equations (24)- (28). C p = 0.0106 × (P) 2 − 0.0609 × P + 0.0323 (27) D p = −0.2778 × (P) 2 + 1.8937 × P − 0.6502 (28) Apart from this, the characteristics of the single clad of Alloy 718 are also dependent upon the tilting angle (α) for material deposition, as previously demonstrated [25], reaching a maximum tilting angle of 30 • . The results of tilting the nozzle when depositing on a horizontal substrate (Figure 9) should be considered for the manufacturing of walls of variable thickness, since, in this case this tilting is necessary and, as it was explained before, the single-clad characteristic change with the tilting.…”