Laser-based production revolutionizes manufacturing

Munich. Experts are forecasting nothing short of a revolution in production engineering due to a technique known as laser-based additive manufacturing. It makes complexity and individuality possible without increasing costs. The international trade fair LASER World of PHOTONICS 2013 from May 13 – 16 and the World of Photonics Congress from May 12 – 16, 2013 – both at the Messe München trade-fair center – will focus on the latest developments and future trends in this sector.

 

Until now, there has been one irrefutable rule in industry: The more complex the workpiece and the smaller the batch size, the more expensive it is to produce. But in many cases, laser-based additive manufacturing renders this rule invalid: “Complexity for free” or “individuality for free” are the latest catchphrases. That is because now the cost of producing a component only depends on how much material is required. Systems create workpieces directly from CAD data, so conventional tools and dies are no longer needed. Instead, these tasks are performed with laser light. This eliminates the costs and the time needed to produce tools and dies – and opens up a realm of possibilities for design engineers. The process has implications that extend far beyond mere production, and it is giving rise to completely new photonics process chains.

Dr. Wilhelm Meiners from the Fraunhofer Institute for Laser Technology (ILT) explains: “Generative manufacturing makes it possible to produce geometries of almost unlimited complexity, including those with internal structures. This makes it possible to design and optimize components for specific functions without having to worry about the restrictions associated with conventional manufacturing techniques.” As part of the Application Panels, the expert from Fraunhofer ILT (serving as Chairman) and Maximilian Meixlsperger from the BMW Group are supervising a session with user presentations on this topic. The panels are part of the World of Photonics Congress, which is held at the neighboring International Congress Center München (ICM) at the same time as the fair and is celebrating its 40-year anniversary together with LASER World of PHOTONICS 2013.

 

Making components from series-production materials layer by layer

All additive processes have one thing in common, i.e. that the part consists of several layers of material, each just a few micrometers thick. In conventional stereo-lithography, plastic that can be hardened with light is applied and solidified by laser one layer at a time. Laser sintering “bakes” plastic, ceramic or metal powder together. But the greatest changes are made with selective laser melting (SLM). In this case, metal, ceramic or plastic powder is melted onto the part in layers. Laser metal deposition can be used for repairs. ILT expert Meiners explains: “The main advantage of SLM compared to other generative processes is the use of metal materials such as AlSi10Mg, a typical casting alloy, or TiAl6V4, a typical implant material.” As a result of the melting process, the workpiece has nearly 100% of the density and, thus, the same strength as the original material – which is not the case when the material beads are “baked” together in sintering. According to Meiners, “as a result, the mechanical properties of SLM components are in the same range as the material specifications.”

 

Cut costs or customize: Advances in medical technology

One of the first application fields is dental technology, where a growing number of dental technicians are using SLM to produce the metal framework for crowns and bridges. Doing so can reduce production costs by a good 50 percent. The final veneering is the only thing that still has to be done manually. This gives Germany a considerable boost in its ability to compete against lower-wage countries. It also speeds up the production process. That is because crown and bridge production can be completely automated and carried out over night. If it becomes possible in the future to scan the teeth directly in the patient’s mouth, there would no longer be any need to take bite impressions, which would save even more time. Generative processes are also giving rise to advances in medical engineering, where they are making it easier to produce customized implants for any patient or drilling templates that can be individually adjusted for each bone operation.

 

Enormous savings in time and materials in production

These processes also offer huge advantages for a number of other industrial applications. A perfect example of a way to save material, costs and time is the manufacture of blade-integrated disks for airplane engines. In the case of these BLISKs, instead of fastening the turbine blades to the hub individually, the entire turbine runner is produced as a single piece. Using conventional techniques to mill the contours from the block of material takes a great deal of time and generates a great deal of material waste. Fraunhofer ILT has used laser deposition welding to manufacture BLISKs, and the process used 60% less material and was one-third faster.

 

Considerable benefits for the aviation and automotive industries

The aviation and automotive industries in particular can also put the advantages of almost unlimited geometric freedom to use for products that are more environmentally friendly. In design, they could exhaust all geometric possibilities to reduce weight. In some aircraft components, the potential savings is 60 percent. In the automotive industry, the weight of a topology-optimized wheel bearing was reduced by 40 percent. These two industries in particular can profit from cost-effective production of small batch sizes using additive techniques. Naturally, aircraft are not produced in large batches. And in the automotive industry, customers are looking for greater individuality. Manufacturers can give it to them by cost-effectively producing small series of individual optional equipment.

 

Replacement parts “on demand” instead of warehousing

Finally, laser techniques are opening up completely new prospects for repair processes. Parts like the BLISKs mentioned above can be repaired affordably using laser deposition welding. In many other cases, maintaining inventories of replacement parts could be eliminated completely. In an ideal situation, the repair shop could immediately produce the needed replacement part itself based on the CAD data. Central storage and spare-part logistics would be superfluous. To promote the use of additive laser techniques, they are being optimized in several ways. One the one hand, systems are getting larger so that they can also be use to manufacture larger components more than 500 mm in size, as Harald Krauss from the Institute for Machine Tools and Industrial Management at TU Munich (iwb) explains. There are also a growing number of potential applications in the other direction. In trials, selective laser micro melting has been used to make components with structures less than 30 micrometers in size, explains Matthias Gieseke from Laser Center Hannover (LZH). In that case, the components were micro-implants that were adapted for specific patients. They are also working on lowering unit costs by using less expensive laser-beam sources and faster systems.

 

In the future, consumers will design products themselves

Completely new business models will also become possible: End consumers will be able to design some products themselves and then send the CAD data to a production service provider who will then produce the desired part as a one-off product or in a small series. Services of this type already exist for Smartphone covers. They call for special CAD programs that laymen can use intuitively. On the one hand, they are supposed to give the user as much freedom as possible, but on the other, they must take a number of restrictions into account to ensure that the designed products are stable and do not violate the trade-mark rights of other companies.