3D printing: The shape of things to come

As laser melting with metals conquers ever more industrial applications, additive manufacturing technologies are changing the production methods of the future.

3D PRINTING has become such a buzzword that it has become one of the most searched technology terms. At trade fairs, 3D printer demonstrations are a huge draw and stir excitement in the automotive, aerospace and medical technology industry – and even the food industry. Even for the average designer on the street, 3D printing has become a hyper-fast DIY conduit to get products out in the market without creating a huge inventory.

With so much creativity out there, the question that begs to be answered is where and how far this technology is taking the metalworking industry, and how fast additive manufacturing will replace traditional component design in an industrial context. IMNA found out from Dr Florian Bechmann, head of Development at Concept Laser, about the current state of technology, and trends and options using laser melting with metals in the near future. Concept Laser is the company behind the development of additive manufacturing using metal powders – the LaserCUSING? layer construction method – for which “industrial applications are currently exploding, literally,” according to Dr Bechmann.

“Laser melting with metals exerts a strong fascination when it comes to the components of the future,” he says. “As the technology leader, we must support this market process by introducing innovations. When it comes to complex systems, we must ensure a wide-ranging interplay between optics, design, control technology, software and the powder material.”

At Concept Laser’s new development center, Dr Bechmann and his colleagues are hard at work on “discrete innovations” not intended for disclosure to the general public due to the sensitivity of these developments for the automotive, medical technology and aerospace sectors, which are defining and driving the additive manufacturing process forward. “These technology drivers not only demand high standards in terms of quality and choice of materials, but also with regard to quantitative aspects, such as increasing productivity. These customers require shorter construction times and more parts in a single build chamber,” he explains.

With the X line 1000R, which currently has the largest build chamber, the goal was to develop quicker processes that are also more affordable. It was developed in close cooperation with laser specialists from the Fraunhofer Institute for the automotive industry, with one application being time-saving development of engines for modern vehicles. “The transition from a 400 W laser to a 1,000 W laser is an important milestone for the process,” Dr Bechmann remarks.

To a certain extent, Dr Bechmann thinks the aerospace sector is driving forward innovations even further with high quality solutions using reactive materials such as titanium or aluminum-based alloys that can only be produced reliably to a high quality in a closed system. “The advantage of this is the ability to produce parts in space using CAD data, provided there is a sufficient stock of powder,” he points out, adding that globally, aerospace agencies agree that additive manufacturing to produce components is the future – perhaps even in orbit on the International Space Station.

The approach is also revolutionizing medical technology. “LaserCUSING parts are in demand as implants since their porous surfaces incorporate well into the body, yet also provide the necessary elasticity. One rising application is the affordable and rapid production of dental prosthetics from biocompatible materials. These are highly adaptable, long-lasting dental solutions instead of dental prosthetics that have to be crafted manually with much effort,” he explains.

Retrofitting and on-site production of components also stand to benefit from the process, say in quickly and affordably regenerating worn-out turbine parts. “This kind of application is relevant in power plant engineering and aircraft construction. In this hybrid technique, layers of the exact same material can be applied additively to the existing part,” he explains. “In addition to regeneration, new whole parts are also produced for turbine technology applications. LaserCUSING also allows functionalities such as cooling channels to be integrated, which improve the performance of components. The offshore industry is considering installing laser melting systems on drilling platforms, which would allow for independent, on-site production of certain components. The technology is not fixed to a specific location and can be operated locally.”

Safety, Quality and Sustainability

Separation of the build chamber and handling area, which is characteristic of Concept Laser products, offers maximum occupational safety and ergonomics. “Handling materials in a closed system has many advantages. It's important for safety, but also to prevent contamination, such as by oxygen,” says Dr Bechmann. “Safety is very important to us. We comply with the ATEX Directive of the EU very conscientiously.”

Dr Bechmann says customers are interested in geometry, density, productivity and, above all – quality. “Two approaches are expedient here: active process monitoring using machine technology and developments in materials. This includes the certification of materials, such as in medical technology, or manufacturer-specific instructions, which must be complied with in the automotive and aerospace sectors.”

Quality Management (QM) Modules are an important distinguishing feature for Concept Lasers that benefit their customers with comprehensive quality monitoring. “Active QA means checking, comparing, analyzing and evaluating process data in real time. We are constantly improving our patented QM Module in order to set the standard in terms of prediction quality and operability, as well as influencing the ongoing construction process,” he says.

QM Module involves two approaches – QMmeltpool and QMcoating – that monitor and document the process, thereby ensuring reproducible quality. “QMmeltpool means that the system uses a camera and photo diode to record signals during the laser process. This data can then be compared to reference values. The optical system is designed coaxially. It allows the camera to record a very small area of the melting pool approx. 1x1 mm2.”

The second approach ensures that the optimal powder quantity is used because only what's needed is used, it saves powder material – up to 25% – while also reducing set-up times. “QMcoating monitors the layer surface while powder is being applied. If too little or too much powder is dosed, the dosing factor is adjusted accordingly, that is, actively counteracted,” Dr Bechmann says.

There are also good reasons why laser melting is considered a green technology. From an environmental perspective, the process is highly sustainable, as Dr Bechmann explains. “On the one hand, due to the localized production options, which reduce logistic complexity, and on the other, because the process reduces the quantity of material required. There aren't any oil or coolant emissions either, as is often still the case in mechanical engineering processes. Even the residual heat can be used. A 1,000 W laser produces approximately 4 kW of heat, which can be used by building systems if channeled into a cooling water circuit.

“Some details are interesting as well: such as filter replacement in processes using reactive materials, such as titanium. The contaminated filter is flushed with water and its contents are then safely disposed of in an environmentally-friendly manner.”

A Look at the Future

Two major areas of applications will benefit from these latest developments in laser melting: process signal analysis in general, also known as the "component map", and the speed of component construction. In the first, 2D maps are generated during the construction process and ultimately be represented in 3D models. “This is comparable to the images from CT measurement, like that familiar from medical technology. This mode of imaging and capability would increase the transparency of the process and captures the component in its structural entirety. Transparency in a highly dynamic, rapid process, which operators can only master with special aids,” Dr Bechmann says.

Speed of component construction figures high on customers' wish lists, he notes. “There are two methods: on one hand, higher laser output, such as in the X line 1000R, and on the other, using multiple lasers. Multiple laser sources will be able to significantly increase the build rate in the future, though the advantage of employing familiar process parameters has to be weighed against the increasing complexity of the optical arrangement. These concepts involve multiplication not only of the lasers themselves, but also of most of the other optical components as well.”