With its LASERTEC 65 3D, DMG MORI presents a hybrid machine that is currently unique on the market, which incorporates additive laser deposition welding in a fully-fledged five-axis milling machine.
DMG MORI has integrated the additive laser deposition process in a fully-fledged five-axis milling machine. This intelligent hybrid solution combines the flexibility of additive component manufacturing with the precision of machining, thus enabling the additive manufacture of complete components in finished-part quality. This procedure uses a deposition process by means of a metal powder nozzle, which enables complete machining without the need of a process chamber and is up to ten times faster than generation in a powder bed. It also makes it possible to produce overhanging contours without a supporting geometry.
The combination of laser deposition welding and machining on one machine opens up completely new possibilities in terms of applications and geometries. In particular large components can be produced cost-effectively with this hybrid solution. In addition the flexible changeover from laser processing to milling makes it possible to machine component segments directly that would otherwise be impossible to reach on the finished part.
The market for additive processes has grown at a rapid rate in the recent past. Until now such processes were limited to the production of prototypes and small parts that could not be manufactured with any other traditional methods. The combining of both processes – additive as well as metal cutting on one machine – has resulted in additive technology complementing and expanding traditional machining methods.
The LASERTEC 65 3D for additive manufacturing is equipped with a 2.5kW diode laser for laser deposition welding, whereby the fully-fledged five-axis milling machine from DECKEL MAHO with its sturdy monoBLOCK design also enables high-precision milling operations.
“With its fully automatic changeover between milling and laser operation, the LASERTEC 65 3D is ideally suited for the complete machining of complex components with undercut as well as for repair work and the application of partial or complete coatings for mould making, mechanical engineering and medical technology”, explains Richard Kellett, Product Manager Additive Manufacturing at Sauer Lasertec.
Producing large parts generatively
In contrast to laser melting in a powder bed, laser deposition welding enables large parts to be manufactured using a metal powder nozzle. With an average build-up rate of 750 grams per hour this process is up to ten times faster than the laser generation of parts in a powder bed. The combination with milling enables a variety of completely new applications. The component can be built up in several steps, whereby milling can be interspersed with deposition welding in order to allow areas to be machined to final accuracy that the cutter would no longer be able to reach when the component is finished due to the component geometry.
The hybrid machine combines the advantages of milling, such as high precision and surface quality, with the flexibility and high build-up rate of powder deposition welding.
“In the case of integral components, where today 95 % of the material is removed by milling, with additive processes, material is only built up where it is needed,” explains Kellett.
The machine is controlled via a 21.5” ERGOline with Operate 4.5 on SIEMENS 840D solutionline. The control for the laser process is housed in a separate control cabinet, which makes it far easier to integrate this system in other DMG MORI machines.
Production of 3D contours
Using a laser diode, the metal powder is deposited in layers onto a base material and fuses with it without pores or cracks; the metal powder forms a high-strength welded bond with the surface. A coaxial inert gas prevents oxidation during the build-up process. After cooling, a layer of metal forms, which can then be machined mechanically.
As laser deposition welding has long been established as a standalone technology, it is ideal for incorporating into DMG MORI’s high-quality CNC machines.
“The combination of chip removal and additive processes will become more important in future, as it opens up many new options and advantages for the user,” says Kellet.
One strength of this process is the option of gradually building up layers of different materials. Two optics are used currently with track widths of 1.6mm or 3mm. Even complex 3D contours can be generated without any supporting geometry.
The individual layers can then be accurately machined before the areas become inaccessible to a cutter or other tools due to the component geometry. The combination of the two processes is an expedient choice for repair work and the production of tools and moulds. However, it also offers many interesting options for lightweight components, prototypes or small series production – particularly in the large-part manufacturing sector where other additive manufacturing processes cannot be used due to limited space.
Economical solution
Large machines, such as those used for machining bulky components in the energy or aerospace industries, tend to be expensive. So reducing roughing, deposition and finishing to a single machine therefore represents a financially advantageous solution for the customer.
What is new here is the generative build-up of two materials in a single component. This entails alternating between powders with the specific aim of uniting different material properties in one component. Combinations of hard and soft materials can be produced in this way, for example. Enhanced component properties and more cost-efficient use of the expensive material are the result.
What is more, component properties can be programmed in advance and generatively and reproducibly manufactured thanks to the CNC-controlled changeover of the powders. This is an advantage for the production of cutting blades in the tool-making branch. A cheap ductile material can be used for the base body, for example, and an ultra-hard material, such as high-speed steel with hardnesses of around 62 HRC, for the blades themselves. First tests indicate a longer service life for the generatively manufactured component due to the clever combination of a tough base body and an ultra-hard blade.
In the energy and oil industry, components very often have to be coated with corrosion-resistant alloys to protect them against wear. Deposition welding provides protection for products such as pipes, fittings, flanges and special constructions intended for use in aggressive environments. With a hybrid solution, machining of the base material, coating and finishing can all be carried out on one machine. This results in cost savings and a reduction in throughput times.