Digitalization: Laser Metal Deposition — The Future of Spare Parts and Repairs for Industrial Steam Turbines

Abstract

Laser metal deposition (LMD) — also referred to as laser deposition welding — has been a well-established process for years. One example of its use is for tip repair for gas turbine blades from Siemens. The decision to also implement laser welding technology for the service of industrial steam turbines was based primarily on the fact that repairs — especially conventional welds and coatings including heat treatment and testing — are very time consuming and are very difficult to reconcile with the overhaul periods planned by customers. The robot supported automation of the LMD process and the fact of its lower heat input, reduced layer thicknesses and the resulting lowered deformation of the part due to reduced coating areas makes it possible to optimize lead times. The high level of process automation and reliability of a laser welding process represents another important benefit. Similarly, process parameters are constantly monitored and tracked, to ensure that the required quality standards are maintained and even increased. Furthermore, laser metal deposition completely replaced the conventional processes such as tungsten inert gas method (TIG), plasma transferred arc (PTA) and detonation spraying. In addition the technology unleashes now the possibility to repair and refurbish parts instead of new manufacturing, and therefore delivery times can be tremendously reduced. Based on the decision to six-axis robots it becomes possible enhancing the LMD process for complex 3D surfaces. After modeling a digital twin in Siemens NX CAM it is possible to generate, optimize and simulate the whole motion-sequences offline before starting the LMD process in the robot cell. So already designed parts in 3D-CAD can be used to develop the final robot program. In addition already existing technologies like 3D surface scanning will be implemented in the chain to support the LMD process. Digitalization turns from a buzzword to an established technology for industrial steam turbine manufacturing and repair.

2022 roadmap on 3D printing for energy

“…Both technologies are already used in manufacturing and/or repair of various turbomachinery components. Prominent examples are the repair of individual damages that occur on turbine blades after being in service, the hybrid production of components (see figure 12) or the flexible production and further optimization of customized parts with highly complex geometries [57][58][59][60][61][62]. In this context, it is crucial that the strengths of the respective technology are used correctly: While DED-LB manufactured structures can be applied directly onto 3D surfaces, PBF-LB manufacturing offers higher detail resolution and freedom of design, but the part must be built on flat surfaces and is supported by a powder bed.…”

Laser Metal Deposition (LMD) Toolpaths with Adaptive Capability for Complex Repairs and Coating Geometries

“…The areas can be detected by the software and the system calculates the toolpaths in previously detected area, with attached process data inside the toolpath. This task reduces the robot or CNC programming due to the part programming is done with and off line methodology [17]. By using this software the operator is able to create automated coating laser strategies for any surface type, additionally the toolpaths integrate the laser process parameters.…”

Reaping What WEEE Sow: The potential for harvesting spare parts for repair and refurbishment

“…Refurbishing and reuse companies, repairers and DIY enthusiasts often use harvested spares, (Hansen & Revellio 2020;Lechner & Reimann 2015). Harvested spares are often a viable strategy to access lower cost spares (see Ijomah & Danis 2012) or reduce delivery time compared to ordering newly manufactured spares (Wittig 2018). Interviews suggested that the increased price of some products has made repair more interesting for consumers (with resulting increases in spare part value).…”