WHO CAN ASSEMBLE AIRCRAFT...
… can also assemble a machine. Until the full-scale production of the world’s most advanced amphibious aircraft, many parts need to be adjusted multiple times. With the STEPCRAFT D.840, the team at Dornier Seawings is able to manufacture prototypes not only flexibly but also on-site, saving time and costs.
However, before Dornier could begin producing the Seastar in mass production, it was necessary to first create a prototype. While major aircraft manufacturers typically build three to four prototypes, Dornier Seawings had to succeed on the first attempt. For this reason, a CNC machine was introduced into the factory to create engineering mockups, installation models for verifying the theoretical CAD design. “CNC technology is very precise and repeatable. That makes it significantly easier for us,” notes Markus Lehmann, who serves as the Production Manager at Dornier Seawings and is responsible for the pre-series production of the Seastar. Initially, he conducted market research on the available machines and quickly realized that industrial machines for the intended use were all too expensive. “Then we might as well outsource it,” recalls the Production Manager. The team needed a relatively large build space but found that with increasing machine size, precision sometimes diminishes. “The 840 was a compromise between size, price, and capabilities,” Markus Lehmann emphasizes, adding, “The available tools, the range of possibilities, and the build quality were decisive factors.
Two days after receipt, the machine was already ready for use. “Anyone who can assemble aircraft can also assemble a machine like this,” says the Production Manager with a smile. The STEPCRAFT D.840 actively supported the Dornier team in prototype construction from then on. This is because it can happen that only during the first installation according to the CAD plan, it becomes apparent that components collide with the structure. Therefore, it sometimes takes five to seven iteration steps until the model is perfect. “With the 840, we can produce the parts as static prototypes as many times as needed until it fits. Only then do we have them manufactured flight-ready from the target material,” explains Markus Lehmann. Mockups are needed for batteries, valves, instrument panels, or connection elements.
Traditionally, the Production Manager receives the corresponding .stp file from the design department when needed. “Of course, I could also outsource the mockups, but then I would wait a week. So, I put it on the milling machine and have it in eight hours,” he explains and continues, “I get the rough concept and then see what fits.” In this process, a variety of materials are used, ranging from Ureol and OBO wood to soft and hard wood, as well as aluminum, carbon, and fiberglass. If Dornier Seawings were to forgo these mockups, the development would be much less flexible, as the development of a flying component costs a lot of money. “If, after development, I say I need the component to be 10 mm shorter, it costs a lot of money again and delays the program,” Markus Lehmann explains. If changes to the part are necessary, he says, “I press a button and have the model relatively quickly in my hands. We are now very flexible in execution and can also experiment without it costing a lot of money,” summarizes the longtime Dornier employee. This way, even last-minute requests can be accommodated, and brackets can be milled or the Seastar logo can be “quickly redone” using the drag knife.
However, the use of the STEPCRAFT D.840 is not intended to end with the pre-series model of the Seastar. “We are building a base model. Once that is finished, the customizations come in,” explains Markus Lehmann. Again, it will be necessary to create prototypes of individual parts to manufacture as efficiently as possible in terms of time and cost. The first aircraft are expected to be delivered to customers by the end of 2020. An exhibition model of the Seastar for trade shows is also already in the planning stage. “If we were to have this externally produced as a wooden model, it would mean costs in the five-digit range,” says the Dornier employee. “The 840 gives us the flexibility to say, ‘Come on, let’s just build a model.’ This way, confidential information stays in-house.” After an intensive year with the STEPCRAFT, Markus Lehmann is certain: “For our purposes, the machine is perfect.” His colleagues share the sentiment. They now have to formally submit a mockup request, as the prototype production on the STEPCRAFT D.840 has addictive potential.