The railway business unit of the Knorr-Bremse Group has launched a test of introducing 3D metal printing in Budapest. The company expects that the new technology will lead to a significant decrease in the manufacturing time of prototypes, individual manufacturing tools, and spare parts.
Once the approval process has been concluded successfully, this would be the first 3D metal printer to be used for the production of brake system parts in the railway business unit of the Knorr-Bremse Group, which is present in 30 countries. Cutting edge railway vehicles already may be equipped with unique printed metal parts the use of which does not represent a safety risk. However, the engineers in Budapest are also planning to manufacture safety critical parts by printing, which is a premiere for this industry. At first, the device will be used to print prototypes and spare parts. Metal printing currently shortens the manufacturing process of prototypes to a fraction. As a result, this device may lend new momentum to research and development in Budapest.
"The fact that Knorr-Bremse is launching its metal printing program in Budapest goes to show the significant role that the Hungarian company plays in the research and development activities of the Group,” said Tivadar Tavaszi, managing director of Knorr-Bremse Rail Systems Budapest. “The possession of this type of technology will make it possible for us to react to customer demands much quicker. Although today there are still many questions related to this method, we will find the answers to them, and prepare the grounds for the wide scope introduction of 3D metal printing in railway brake manufacturing.”
Additive technology in vehicle manufacturing
The difference of additive technology (commonly called 3D printing) to traditional casting and cutting technologies is that it builds up the part to be manufactured layer by layer. Its advantage is that objects can go straight from the design software to the manufacturing device. This means that there is no need to adapt existing manufacturing lines. As a result, even one or only a few products can also be manufactured cost efficiently. In addition, lead times are shorter, and the need for raw materials and tools is lower.
The printer deployed at Knorr-Bremse Rail Systems uses the DMLS (Direct Metal Laser Sintering) technology. When printing, a laser beam with a power of approximately 400 watts melts the metal dust that is placed into the printer and that consists of particles of 20 to 30 microns in size. Depending on the material chosen, the printer builds up the desired object, which can be made of aluminum, steel, or titanium in 0.02 millimeter layers.
As the laser beam melts the metal dust layer by layer, the granulation of the material created is different from that of traditionally produced metals, just as its physical properties are different. In addition, different granulations can be achieved by changing the direction of the laser beam. The “digital metal” created using this method is subjected to complex tests at Knorr-Bremse Rail Systems Budapest, but according to experiences gained in the automobile industry where printed metal parts are already being used, the quality of printed metal is not expected to be any lower than that of metal produced using traditional technologies.
Less raw materials and energy
In addition to being much faster than traditional processes, 3D metal printing requires much less raw materials and tools, as well as less energy than casting and cutting. In addition, the technology also makes it possible to create geometric shapes which are not possible using current methods, and the mass of products can also be decreased.
In the coming months, the company will thoroughly examine the printed parts, but based on experiences from other industries, their quality may be better than that of cast or cut parts. Currently, it pays off to produce in low numbers and with short deadlines using additive technology. As costs decrease, and taking the advantages mentioned into account, printing may replace current production technologies in the manufacturing of railway brakes in the case of certain product categories and parts—all this, however, rather in the far then the near future.
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