Additive Manufacturing Hybrids on the up

Author / Editor: Martin Courtney, Freelance Journalist / Barbara Schulz

Germany/UK - Aerospace and other manufacturing sectors likely to adopt hybrid machine tools once volume production brings costs down.

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A laser adds material in DMG Mori's hybrid machine Lasertec 65 3D.
A laser adds material in DMG Mori's hybrid machine Lasertec 65 3D.
(Bild: DMG Mori)

The emergence of hybrid machine tools that combine additive manufacturing (AM) processes with traditional substractive technologies in CNC milling machines has sparked considerable interest in the machine tool industry.

“Opposed to most standalone AM systems, hybrid machines can produce ready to use components directly from the manufacturing chamber,” explained Dr Myron Graw, partner at KEX Knowledge Exchange, a professional technology and information market provider specialising in machine tool technology.

KEX Knowledge Exchange is currently working with the Fraunhofer Institutes for Production Technology and Laser Technology to build an industry consortium focused on the development of hybrid AM machinery which combines milling functions.

“These machines combine the best of two worlds - good surface quality and repeatability achieved by conventional processes as well as high complexity and individualization achieved by AM,” says Graw.

Technology and market development

For all their potential, it is estimated that hybrid machines currently represent only a tiny fraction of the overall AM systems market, with early units supplied by DMG Mori, Hermle, Ibarmia, Mazak and Trumpf.

DMG Mori in particular has proved instrumental in driving the technology forward by bringing reliable, fully tested hybrid prototypes into the commercial market backed by a strong reputation for reliability and support, adds Graw.

The company developed a hybrid machine tool that combines laser metal deposition for AM with 5-axis CNC milling in late 2015, with the technology now integrated into the Lasertec 65 3D unit. The machine uses both a powder nozzle and traditional cutting to enable new applications and geometries, and is designed especially for the production of larger components up to 24in wide weighing up to 1,322 pounds.

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Hybrid Manufacturing Technologies (HMT) is one of four companies that worked collaboratively to develop and produce the Hybrid HSTM 1000 two and a half years ago. HMT built the docking system to enable services to be coupled to the laser cladding head, whilst the UK’s Manufacturing Technology Centre (MTC) provided the laser cladding head itself along with parameter development and material science. German company Hamuel Reichenbacher constructed a large high-speed 5-axis HSTM 1000 mill-turn machine tool and Delcam provided adaptive CAD/CAM software, which coordinated and drove the milling, inspection and cladding throughout the process.

Although the Hybrid HSTM 1000 is capable of new component production, HMT founder Dr Jason Jones says for the moment its commercial use is limited to blade repair.

“There is a whole lot of research and marketing around trying to build parts from scratch and I think we will see a lot more of that,” says Jones. “But building complex 3D parts quickly in metal, that does not quite exist in any format.”

Manufacturers building parts for use in the aerospace industry are widely expected to embrace hybrid machine tools sooner than most once regulatory requirements are met, however.

“We are seeing at least some hybrid activity on blade repair, and now that has certifications it becomes far more interesting for aerospace to move ahead,” says Jones. “From a blade repair standpoint it [aerospace] is right on the cusp [of adoption] but from full or partial component manufacturing it is still two to three years away – you have to go through the design cycle because you really get new products and processes ingrained.”

Graw highlights a range of potential components suitable for manufacture using AM technology which were problematic previously, including tool and die inserts with complex internal cooling channels; hydraulic manifolds with improved weight and less fluid dynamic energy loss; and weight and topology optimised fuel, blade structures and brackets. He also predicts significant interest from the aerospace industry, alongside healthcare and tool and die making – but says hybrid machine tools are suitable for use in any vertical sector with a requirement to manufacture complex, customised low lot size components within high margin markets. “Hybrid manufacturing makes these even more interesting since it has the potential to lower manufacturing cost whilst increase product quality,” says Graw.

In contrast, the automotive sector is a very high production volume, low margin market with very high degrees of component standardisation, a situation that makes it hard for AM to compete with conventional manufacturing processes.