Generative Manufacturing and Repair of Metal Parts through Direct Laser Deposition Using Wire Material

Abstract

Abstract. In the field of Laser Additive Manufacturing, modern wire-based laser deposition techniques offer advantageous solutions for combining the high quality level of layer-by-layer fabrication of high value parts with the industry's economical requirements regarding productivity and energy efficiency. A newly developed coaxial wire head allows for omni-directional welding operation and, thus, the use of wire even for complex surface claddings as well as the generation of three-dimensional structures. Currently, several metallic alloys as steel, titanium, aluminium, and nickel are available for the generation of defect-free structures. Even cored wires containing carbide hardmetals can be used for the production of extra wear-resistant parts. Simultaneous heating of the wire using efficient electric energy increases significantly the deposition rate and energy efficiency. Examples of application are light-weight automotive parts, turbine blades of Nickel super alloys, and complex inserts of injection moulds. IntroductionLaser buildup welding is a well-established technique in industrial applications of surface cladding and direct fabrication of metallic parts. As construction materials, powders are widely used because of the large number of available alloys and the simple matching with the shaped laser beam. However, the powder utilization is always less than 90 %, characteristic values are in the range of 60 %, and so a serious part of the material is lost. Additionally, there is a risk for machine, operators and environment due to dangerous metal dust. The alternative use of wires as buildup material offers a number of advantages: The material utilization is always 100 %, and rightly independent from the part's shape and size. The process is clean and safe, and so the effort for protecting personnel and environment is much less. Also the wire feed is completely independent from the gravity which is of great advantage especially in applications of three-dimensional material deposition.The main challenge compared to powder is the realization of an omni-directional welding operation with stable conditions of the wire supply. The only possible solution therefore is to feed the wire coaxially in the centre axis of the laser beam. This technology requires a complex optical system which permits the integration of the

Optimal planning in robotized cladding processes on generic surfaces

“…Furthermore, as shown in refs. [12,18], and exploiting new laser-head designs, 25 cladding displays a larger orientation tolerance around the normal axis of the surface than do the cutting processes studied in ref. [24].…”

“…Figure 5 displays the object to be cladded, and Fig. 6 shows the COAXwire head (a processing optic for laser-wire cladding, developed in Fraunhofer IWS 25 ) that was used in the experiments. The COAXwire head is characterized by a wide ϑ max angle because of minor energy absorption problems (common in powder-based solutions).…”

Error Investigations for a CT and Additive Manufacturing based Reverse Engineering Workflow

“…For instance, the realization of new cooling designs has become possible by use of additive manufacturing driven production [2]. Currently, similar AM-based methods are also available to repair damaged or worn out turbine blades [3]. However, to our knowledge there is currently no existing means of directly replacing a damaged part as a whole, without further detailed knowledge about its geometry, e.g.…”