Process characteristics in high-precision laser metal deposition using wire and powder

Abstract

Meanwhile laser-based Additive Manufacturing (AM) technologies such as Laser Metal Deposition (LMD) have been introduced in various fields of applications. The latter is not only used for the fabrication of complete new parts, but also for the purpose of repair and redesign. Therefore, weld beads with dimensions above 1 mm were mostly used in the past. In some cases, bead widths can even exceed 10 mm or more. However, the build-up of filigree parts by means of sub-millimeter structures has gained interest during the several last years. Fabrication of structures with small dimensions requires different process modifications along the process chain. This includes general process strategies but also adjusted system components. The changed process yields material deposition of varying geometries possibly used in aerospace, space, medical technology as well as micro tooling. Additionally, it can be also used for the repair of worn or damaged micro parts.Within this paper, the aforementioned process modifications are shown and demonstrated. In addition, high-speed process observations are discussed and, finally, fabricated parts are analyzed. The latter includes non-destructive and also destructive methods. Based on the combination of changed process elements, a stable laser-based AM procedure is presented which is already in production.

Laser Implantation: An Innovative Technique for Surface Texturing

“…Since one-step processes commonly require a synchronous movement of the laser beam and the material feed, the texturing speed is strongly limited. Texturing of large parts is very time consuming and the application of the laser microcladding technique for industrial application still not in sight [4,5].…”

Additive Manufacturing of β-NiAl by Means of Laser Metal Deposition of Pre-Alloyed and Elemental Powders

“…Laser metal deposition (LMD, also referred to as direct energy deposition) is a well-known process for the coating and refurbishment of parts, and has recently gained a great deal of attention regarding its application as an additive manufacturing (AM) technology [ 9 , 10 , 11 , 12 ]. The basic principle of LMD is depicted in Figure 1 .…”

“…Figure12. EDX mapping of the Ni (a) and as well as Al (b) content within of a weld track deposited at 900 • C pre-heating temperature, 800 W laser power and 400 mm/min feeding speed.…”

Low-Roughness-Surface Additive Manufacturing of Metal-Wire Feeding with Small Power

“…The SLM is mature and has high printing precision, because of the use of small powder sizes (15–40 μm) and optimization of process parameters that enable the surface roughness of parts to be reduced significantly, to 6–20 μm for SLM techniques [ 7 , 8 ]. However, it has disadvantages, e.g., expensive raw materials, the lower utilization efficiency of materials (20–30%), and poor density [ 9 , 10 ] and so on. More importantly, the SLM cannot be used in a microgravity environment where the motion of the powdered particles is beyond control.…”