Blue laser for additive manufacturing of reflective materials

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At the formnext 2022 international trade fair for additive manufacturing (AM) and allied processes from 7-10 November, DMG Moriwill feature its LASERTEC 30 DUAL SLM (selective laser melting) metal powder-bed machine linked to one of its DMP 35 vertical machining centres for post-processing the 3D-printed components.

The manufacturer will also present a 5-axis LASERTEC 65 DED hybrid machine that combines metal AM by directed energy deposition with milling and drilling. It incorporates a newly developed blue laser with a wavelength of 450 nm whose power is absorbed efficiently by reflective materials. It enables the processing of pure copper, for example, for which the absorption rate is 44% compared with two percent for infrared light.

Due to its high thermal conductivity, copper gives injection moulds and forming tools improved cooling properties, while in the aerospace sector it is used in nickel-based superalloys to form heat shields. The good sliding properties of the non-ferrous metal also open up new applications for coating bearings.

Many multi-material components such as a die casting mould with a bronze core can only be realised by AM. A LASERTEC 65 DED hybrid is able to build up the core, mill highly functional cooling channels in it and then deposit a layer of hot-work tool steel in the same process, ensuring optimum heat dissipation during casting.

Mould repair is another application for machines in the LASERTEC DED hybrid series. Material is first applied to the damaged area and then milled on the same platform to achieve a high quality repair equivalent to the original surface.

In the case of the twin-laser LASERTEC 30 DUAL SLM, an additively manufactured workpiece can be transferred to the 5-axis DMP 35 machining centre, where it is milled to achieve the required surface quality. Alternatively, the AM machine is able to finish a previously milled component in the powder bed, without the need for support structures. A zero-point clamping system provides an accurate interface for transferring the component between the powder bed and CNC machine, while DMG MORI's app-based CELOS control ensures a continuous digital workflow.

Featured also at the show will be DMG MORI's AM Assistant, a combination of hardware and software that ensures a stable process in its directed energy deposition machines. It continuously monitors and controls all important process parameters such as laser power, powder mass flow, shielding gas, melt pool size and temperature, and clearance between nozzle and component.