Recently, Ohnhäuser has been using a Behringer HBE320-523 3D horizontal bandsaw to separate additively manufactured aerospace parts from the printing plate quickly and efficiently.
The HBE320-523 3D and a vertical bandsaw, the LPS-T 3D, are relatively new additions to Behringer’s portfolio. Both high performance machines were developed to separate additively manufactured parts of different shapes and sizes.
The additive manufacturing of components continues to gain a foothold and gather pace, particularly in applications where typical production techniques reach their limits. One of the clear advantages of 3D printing technology is the seemingly limitless shapes and structures it can produce. Even a moving group of parts can be printed as a complete unit, so there is no need for post-production assembly.
To manage the demands of manufacturing bionically constructed parts, Ohnhäuser GmbH expanded its production methods to include additive manufacturing (AM). In the latest stage of development in 3D printing, Ohnhäuser is concentrating on the use of a special titanium powder, optimised for aerospace requirements. As a material, titanium offers strength characteristics in the range of tempered steel with a comparatively low weight. An EOS M 290 printer is used to generate the 3D metal parts.
After additive manufacturing, the titanium parts must be separated from the printing plate. While carrying out research into a suitable separation process it became clear that only a sawing system would make the cut: “We then contacted Behringer to ask solutions they could offer,” recalls Ohnhäuser’s Moritz Färber. “We’ve been using a Behringer bandsaw for several years, so we knew the company manufactured high-quality, reliable machines.”
When it comes to highly-sensitive 3D printing, accurate separation of the part from the printing plate is essential. Deviations in the cut or drifting out of the cutting channel is not permitted, as this would damage either the baseplate or the printed parts.
The Behringer HBE320-523 3D is based on the established HBE Dynamic series, which offers robust construction, an energy-efficient drive system, and highly accurate – to tenths of a millimetre – sawing in a variety of materials such as steel, aluminium, nickel-based alloys, titanium and plastic.
The bandsaw blades can also be changed rapidly to suit a specific material. All the machine’s blade-guidance parts are cast in Behringer’s in-house foundry. The grey cast iron construction dampens vibration and reduces background noise during cutting – all of which have a positive effect on the sawing process. The result is high cutting performance and a long bandsaw service life.
The HBE320-323 3D is optimally designed for productivity. Once the base plate has been clamped, it is quickly and precisely aligned for the saw cut using the measuring stop. The stop system is located on the printed side and works regardless of plate size. This eliminates the majority of the setting and alignment work.
Regarding the loading and clamping processes, Behringer caters to customers’ individual needs. “It is very important that we are flexible in this regard as the process often depends on the 3D printer design itself,” explains Rolf Bentz, project manager at Behringer.
Some of the metal powders used in 3D printing have a tendency to self-ignite. After printing, the residual powder is removed from the finished parts, but powder which is embedded in supporting structures can pose a hazard. To separate these materials, 3D saws from Behringer can be equipped with an enclosure which is connected to an extraction system. Metal dust, vapour and oil/aerosol mists that arise during the separation process can be directly extracted.
The cooling system should also be matched to the material being sawn with flood coolant recommended for the majority of materials to ensure efficient sawing of parts. The models in Behringer’s 3D series are equipped with a filter system which continuously cleans the metal powder particles from the coolant. However, when aluminium alloys are being processed, for example, reactions with the coolant (water-oil mixture) can occur and promote the formation of explosive hydrogen. Micro spray systems are suitable for such cases.
The HBE320-523 3D has now been in daily use at Ohnhäuser GmbH for over a year. “We are very satisfied with this machine,” says Moritz Färber. “The saw cut is precise and a solution-based approach has been taken with the material handling. We also appreciated the open dialogue with Behringer so that our machine could be optimally adapted to our machining process. Together we have developed a special, hydraulic quick clamping system for easily securing the printing plate to the fixture,” he adds.
The HBE320-523 3D can be used to process printing plates up to 300 x 300mm. For larger sizes, Behringer offers the LPS-T 3D which can accommodate printing plates up to 850 x 650mm. When using a crane to load and unload the larger, heavier base plates, the vertical machine design with freely accessible machine table is a good choice.