Additive manufacturing with metals in automotives

Paul Boughton

Ilona Scholl looks at the development of a metal laser melting machine for the automotive industry.
Additive manufacturing with metals is becoming increasingly important in the automotive industry. Time and cost reductions in production are making this generative technology increasingly attractive to the carmakers.
The primary focus is on aluminium alloys which provide the basis for lightweight automobile construction. For applications involving vehicle and engine technology, but also from other areas, Daimler AG is now consistently embracing the resource-efficient, generative metal laser melting of metals.
In order to meet all future assignments, the Swabia-based company got the Fraunhofer Institute for Laser Technology (ILT) and the LaserCUSING specialist Concept Laser to develop a new super laser melting machine X line 1000R whose build chamber size surpasses anything that was known previously.
The Fraunhofer ILT and Concept Laser created the new high-performance LaserCUSING machine X line 1000R for fabricating series components in an XXL format. The first machine is already in operation at Daimler AG.[Page Break]

Pilot machine

The large machine X line 1000R boasts a superlative build chamber which, according to Frank Herzog, managing director of Concept Laser, has impressive dimensions. The X line 1000R was developed for the tool-less manufacturing of large functional components and technical prototypes with material properties which are identical throughout the range. The centrepiece of the X line 1000R consists of a high-power laser in the kilowatt range which enables an increase in productivity of up to a factor of 10 compared with standard laser fusing machines available on the market.

The machine was specifically configured to cater for Daimler AG's special requirements for automobile applications. The aim of Daimler AG was to replace costly sand-casting and die-casting applications in early phases of development. In addition, the LaserCUSING process will in future offer the possibility of generating lightweight structures with a high level of rigidity which will permit weight-optimised geometries, with almost no restrictions on the design, but at present cannot be manufactured in this way with the manufacturing techniques which are available today.

The project partners got together as part of the 'Alu generative research and development project (German Ministry of Education and Research)'. The Fraunhofer ILT examined, together with different partners from industry, including Daimler AG, the laser fusing technology for production applications involving aluminium components.

The industrial use for fabricating production components was previously, mainly as a result of the materials and costs, restricted to smaller components or dental and medical technology.

As part of the project, the application potential for manufacturing aluminium components for other areas of industry was examined. The well-known characteristics of the production process include conservation of resources, independence from mould-making, freedom of geometry, as well as the speed of construction and development. These were appraised at Daimler as a fundamentally new way of looking at manufacturing options with the aim of creating innovative and environmentally friendly products. From the point of view of the development partners, these also provided a solid basis for tackling the pressure of costs in production and safeguarding Germany's long-term future as a place for high-tech manufacturing.[Page Break]

Automotive construction

The demands of Daimler AG as an industrial partner were a significant increase in the build-up rates, an improvement in the quality of the surface finish, reproducibility and reliability of the machine as a result of appropriate process monitoring, as well as the qualification of further aluminium series alloys for a range of applications.

The Fraunhofer ILT, which has been one of the leading research institutions in the field of laser melting for over 15 years, supplied its know-how for designing the kW laser beam source and the matching optical lens system in order to ensure the desired build-up rates of different aluminium alloys. In addition, the process control for processing the different alloys alongside the machine construction was worked out and the mechanical properties of the components were examined.

The preliminary work now needed to be turned into 'solid' machine technology. In parallel with this, the functional specification was drawn up at Concept Laser in Lichtenfels together with the partners and the design phase for the new X line 1000R was then started.

The findings obtained in the meantime by the Fraunhofer ILT, eg in relation to temperature control of the build chamber in order to avoid any warping in the 'oversized' components, and in relation to the design of the powder application system, were consistently implemented in the design of the X line 1000R.

"This really was uncharted territory for us. The development of a machine concept of these dimensions in close collaboration with Daimler AG and the Fraunhofer ILT, based on our LaserCUSING technology, clearly illustrates our claim to be the technology leader in the field of laser melting. This patented, top-class machine technology from Concept Laser has been exported throughout the world since 2000. As a result of the cooperation project with Daimler and the Fraunhofer ILT, we hope that the generative machine technology will meet customers' requirements on a broad basis and that it can be employed profitably," says Frank Herzog in reflecting on the co-operation project. For the development of parts at Daimler AG, the high and flexible availability of such a machine opens up entirely new possibilities for further optimisation of the product development process.

The LaserCUSING process allows the fabrication of both mould inserts with close-contour cooling and direct components for the medical, dental, automotive and aerospace sectors. Both prototypes and mass-produced parts are manufactured.

Standard machines and customer-specific machine concepts for the LaserCUSING of metals are on offer. Full service as an option at Concept Laser means that customers can purchase machines for their own independent LaserCUSING application, or access services and development expertise (prototypes and small batches) directly.

The laser processing machines from Concept Laser process powder materials from high-grade and tool steels, reactive aluminium or titanium alloys, nickel-based superalloys, cobalt-chromium alloys and in future will also process precious metals such as gold and silver.

The machines make it possible to shorten development times and reduce development costs considerably. The key benefits of LaserCUSING include greater freedom of geometry, coupled with much greater flexibility in terms of product development. Another central advantage of the process is the opportunity to produce components without the use of tools and the obviation of the machine programming associated with this.

Enter at √

Ilona Scholl is with Concept Laser GmbH, Lichtenfels, Germany.

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