Unique applications of Laser Metal Deposition technology

Laser Metal Deposition (LMD) technology (= Direct Metal Deposition DMD) is applied to build near net-shape 3D components [1] with applications covering a broad range of industries. LMD also has some unique capabilities that are absent in the powder bed selective melting and sintering processes. We quickly review here its unique features.

Repairing and remanufacturing

Repairing worn components typically saves money compared to purchasing new ones. In addition, when a worn part is rebuilt, that component can be coated with harder materials by LMD to ensure it will have a longer wear life. Also, repairing parts previously considered non-repairable by conventional methods [2] has become routine practice using LMD technology. 

Repair stages of a titanium bearing housing.

Turbine blades

Typical applications for LMD are turbine blades/vanes repairs [3]. The concentrated heat from the laser allows blade tip build-up with minimum distortion. The vision system and closed loop feedback system integrated in LMD machines offer precision part positioning and refurbishment to ensure high quality repairs with minimal need for post-processing. [4]

Drive shafts

Another feasible application of LMD is the repair of drive shafts [2]. Bearing, seal, and coupler surfaces on shafts, which are typically considered non repairable by conventional welding techniques, are perfect candidates for buildup and repair utilizing LMD/DMD. 

Repair stages of an atomizer shaft using 420 steel deposit and post-machining.

Cladding and hard-facing

Cladding and hard-facing are a form of repair build up applied to deposit new layer(s) of material on a substrate. Multiple layers can be deposited to form shapes with complex geometry. These two variants of LMD have been used for material surface property modification and for the repair and manufacturing of multi-layer coatings [5]. Large DMD workstations exist for hard-facing and repair/cladding of large dies, molds, and components [6]. The surface finish of the cladding may be left as-deposited or ground to finish dimension. [7] 

Material design

One of the unique characteristics of closed loop DMD technology is that multiple materials can be deposited in different parts of a single component with high precision.

This capability can be utilized to develop a new class of optimally designed materials, i.e., a class of artificial materials with properties and functions that do not exist in natural environments. In other words, a material system can be designed and fabricated for a chosen performance [8, 9].

References
1. Dutta B, Palaniswamy S, Choi J et al (2011) Additive manufacturing by direct metal deposition. Adv Mater Process 169(5):33–36
2. Mudge RP, Wald NR (2007) Laser engineered net shaping advances additive manufacturing and repair. Weld J 86(1):44–48
3. Dutta B, Singh V, Natu H et al (2009) Direct metal deposition. Adv Mater Process 167(3):29–31
[4] Additive Manufacturing and Characterization of Rene800 Superalloy Processed Through Scanning Laser Epitaxy for Turbine Engine Hot-Section Component Repair, Ranadip Acharya, Rohan Bansal, Justin J. Gambone, Max A. Kaplan, Gerhard E. Fuchs, N. G. Rudawski and Suman Das, ADVANCED ENGINEERING MATERIALS 2015, 17, No. 7, DOI: 10.1002/adem.201400589
5. Zhong M, Liu W (2010) Laser surface cladding: the state of the art and challenges. Proc Inst Mech Eng C 224 (C5): 1041–1060
6. The POM Group Inc. http://www.pomgroup.com
 [7] Evaluation of microstructure and fatigue properties in laser cladding repair of ultrahigh strength AerMet® 100 steel Shi Da Sun, Martin Leary, Qianchu Liu, and Milan Brandt Citation: Journal of Laser Applications 27, S29202 (2015); doi: 10.2351/1.4906377 View online: http://dx.doi.org/10.2351/1.4906377
[8] https://asm.confex.com/asm/aero15/webprogram/Paper39608.html
[9] Microstructural control during direct laser deposition of a b-titanium alloy Chunlei Qiu, G.A. Ravi, Moataz M. Attallah Materials and Design 81 (2015) 21–30 http://dx.doi.org/10.1016/j.matdes.2015.05.031