In the market of additive manufacturing, DMG MORI is concentrating on the integral combination of laser-assisted material build-up and chip removal, while promising unrestricted freedom of design with utmost precision and surface quality.

In times of increasingly complex and individualised components, additive manufacturing processes with their high degree of geometrical freedom regarding component design are an effective way of escaping the complexity trap. However, the technology is slow, inaccurate and expensive which, up to now, has made it difficult to make inroads, particularly in the field of metal processing.

Against this background, the combination of laser deposition welding by means of a powder nozzle with chip removal opens up fully new perspectives. As a pioneer and trendsetter, DMG MORI is already offering two groundbreaking hybrid machines.

We spoke to Friedemann Lell, Sales Manager of SAUER, who is responsible for additive laser technology in the DMG MORI Group, about the advantages and areas of application of the combi-machines.

AMT: What is the difference between the LASERTEC 3D machines and other additive metal processing systems?

Friedemann Lell: In the field of additive manufacturing, we are focusing on powder deposition welding using lasers, a technique which has basically long been used for carrying out repairs, for example in tool making and in engine construction. In this process, the powder is melted onto the base material by the laser beam. On the other hand, other laser-based additive manufacturing processes work using the layer principle, in which a component is built up from powdered material layer by layer.

AMT: What advantages do powder deposition welding using lasers offer compared with layering?

FL: First of all, I would like to point out that we also build up components layer by layer, but only use powder where it is necessary. As a result, the use of powder is significantly less than with classical powder bed systems. In addition, with powder deposition welding, the material can be built up around 10 times faster than in the powder bed. But even more decisive for us is that the process is ideal for incorporating into our high-tech machines, thus enabling an integral combination of additive manufacturing and chip removal. In this way, we offer the customers the best of both worlds!

AMT: What are the customer benefits?

FL: Although additive manufacturing may be fascinating with regard to the almost unrestricted geometrical freedom in design, all processes are painfully slow. In addition, the components generated bear no comparison with the excellent results of conventional machining with regard to accuracy and surface quality. By combining additive manufacturing and chip removal, we achieve geometrical freedom while chip removal brings the precision and quality for the component.

AMT: Couldn’t you just use two separate machines in tandem?

FL: Sequential manufacturing would cancel out an elementary advantage of our LASERTEC 3D machines.

Firstly: In component design, geometrical freedom is the strongest argument for the use of additive manufacturing because it is unique. Otherwise, as a single technology, the process is too expensive, too slow and too inaccurate, at least as far as our target market in metal processing is concerned.

Secondly: Geometrical freedom means that workpieces have altogether new levels of complexity. Internal cooling channels for injection moulding tools or freely formed geometrical elements in turbine and engine manufacture are just two concrete examples. If these components were to be produced sequentially, it would no longer be possible to achieve many of the contoured areas of the workpiece using a lathe, milling machine or grinding machine after additive manufacturing.

And thirdly: By combining the processes in our LASERTEC 3D machines, the user is able to first build up the component to a certain height using laser-assisted powder deposition welding and subsequently to machine certain areas where necessary. Especially large components are built cost-efficient in that way. As a result, freely formed workpieces in the truest sense of the word are produced with the utmost precision and excellent surface finish thanks to a unique interplay between technologies.

AMT: As well as the LASERTEC 65 3D, DMG MORI has launched a second machine – the LASERTEC 4300 3D. What are the differences between these products?

FL: In its basic form, our LASERTEC 65 3D is a classic five-axis machine for high-precision milling operations up to five-axis simultaneous machining. For additive manufacturing, it is equipped with a 2.5kW diode laser. As well as the complete hybrid production of components, the machine is also suitable for carrying out repair work and applying partial or full coatings, for example in tool and mould-making.

As well as laser deposition welding and five-axis milling, the LASERTEC 4300 3D, which was launched during the Innovation Days event in Chicago in June and will go into serial production at the beginning of next year, also brings turning into play. This now enables rotationally symmetrical components to be produced using the hybrid process. Fitted with a mirrored C-axis, workpieces can even be fully finished on the rear and therefore on a total of six sides by means of the counter spindle. Even longer workpieces are no problem, as in this case, the lower tool turret supports the component during the manufacturing process.

With both machines, the laser, including the powder build-up head, is optionally mounted in the Capto or in the milling spindle HSK tool holder and introduced automatically as required. Another special feature of the LASERTEC 4300 3D is that up to five powder build-up heads are available for different operations – for example for internal and external coating of cylindrical components. This provides additional degrees of freedom for the manufacturing strategy.

AMT: You have several LASERTEC 65 3D machines in the market. What has been your experience and, an associated question, is additive manufacturing already a standard process?

FL: Practice confirms our expectations and, even more importantly, those of the customer. However, I would not go so far as to describe additive manufacturing as already being standard technology. That would awaken false expectations. Additive manufacturing, particularly in the field of metal processing, is a complex process where the result depends on the perfect interplay between machine, material and process like nowhere else. For example, it follows from this that the process must be redeveloped in all its parameters for every material. In this regard, we provide intensive support for our customers. We also co-operate very closely with research institutes in the field of material and process development.

AMT: What does this mean for the further spread of additive manufacturing in the metal processing industry?

FL: Driven by the fascinating possibilities of the process and based on ever more frequent and more imposing successes currently, particularly in aircraft manufacturing, engine and turbine technology, and medical engineering, additive manufacturing is one of the technologies for the future in the metal processing industry. This is also true particularly against the background of the digitised process chain in the Industry 4.0 age and the trend towards individualised products. Anyone wanting to manufacture finished products directly from CAD data will need additive manufacturing. And if they also want excellent surface finish and high precision, they will need our hybrid machines.