The Perfect Storm

AMD: What sort of trends and new technologies has Siemens witnessed over the past few years in the Aerospace Industry?
TIM: In the last two or three years, big programs have been coming along. The effect, however, has been that current capacity in the supply chain is far below what is required to meet the demand in the coming number of years. Also, the primes will be divesting some of their manufacturing sites, looking for risk sharing partners to take over those sites. They are moving away from detailed manufacturing, and are embracing a model where they outsource most of the machining and subassembly. On the technology side of things, the obvious trend is composites for the major structural components. In the defense world it's been there for a while; in the commercial world, the 787 is the most composite large aircraft ever designed and built. One resulting effect is that we're seeing an increase in titanium as we're seeing an increase in composites. The other trend we're seeing in technology is larger, monolithic parts. Instead of a sub-structure being made up of a hundred smaller parts, they try to manufacture that out of one or two larger parts. Along with that, because these parts are getting bigger, that's driving the requirement for larger machine tools. Also, we've seen a decrease in the tolerance allowed, especially in the defense world, where the volumetric tolerances are about 2/3 of what they had been on previous programs. These trends create a kind of contradiction, where we have ever-increasing machines, but ever-tighter tolerances. That's obviously a manufacturing challenge in and of itself.

AMD: Boeing's goal is to reduce aircraft weight to improve fuel efficiency. Is Siemens prepared to help Boeing achieve this goal? How?
TIM: We have been investing and collaborating with Boeing to advance technologies in the process of laying down both carbon fiber and tape. The goal of this collaboration and investment is the increase in throughput of these composite machines necessary in order to achieve the production levels that are required at the run rates of these new programs. To meet production demand, you can either have a machine that can make 5x as many parts as traditionally, or you have 5x the machines. They can't build enough composite machines at current technologies or current lay-down rates to meet the capacity when all three of these programs start hitting their strides. That's why we're working with the machine builders and the primes like Boeing and AIRBUS to develop features that would allow greater throughput. That's the whole goal: instead of having 1,000 machines to create 1,000 parts a year, you have 100 machines to create the same 1,000 parts per year. The industry has to come up with a way to make these composite parts faster.

TIM SHAFER BIOGRAPHY

Name: Tim Shafer
Title: Director, Aerospace Center of Competence
Company: Siemens Energy & Automation, Inc.
Location: Mason, OH
Years in the industry: 20
Years with Siemens: 7

AMD: Would you explain the term "volumetric compensation", and Siemens' approach to working with aircraft manufacturers in this area?
TIM: Volumetric compensation actually addresses volumetric accuracy. Volumetric accuracy is the ability to position the tool tip in 3D (XYZ) inside the work envelope. You position the tool tip at various spots in that volume and record the positional error, and then you do a calculation and estimate what the volumetric accuracy of that machine is. Volumetric compensation is the ability to put that tool tip in a more accurate position within that work envelope. To differentiate between accuracy and repeatability: a repeatable machine will position to the same inaccurate location. If a machine is not repeatable, it will never be accurate. In other words, you can't take a bad machine and make it good; you can take a good machine and make it better. And that's what volumetric compensation does.

AMD: What solutions can Siemens provide to the aerospace industry as it pursues new equipment and cutting tools to efficiently machine Ti5553?
TIM: With Titanium, you're typically not doing high speed machining. What you want to be able to do is cut a smooth, contoured, 5-axis surface. Surface finish is probably one of the most important parts when it comes to cutting 5553. Some of the technologies that enable that are internal kinematic transformations, polynomial surface definitions such as nurbs, and also a similar type of surface definition but doing it with two splines instead of one. The second thing that I think is important is the ability to simulate and verify the part program before you start cutting. Part-verification has been around for many years, but just recently, there has been an advancement that enables accurate part verification. Verification companies have to guess at what the CNC is going to do because they don't have access to the CNC's proprietary algorithms. To solve that problem, and to make verification more accurate, what we've done at Siemens is create a re-locatable software module of the CNC real-time kernel that is placed inside of the verification software; we take out their software module that guesses what the machine will do, and we run that program input directly into a virtual CNC software module. The simulation program shows cutter path and so forth – and it's not a guess anymore, it's exactly what the machine will do. Siemens' name for this is Virtual NC Kernel, or VNCK, and not only is it a re-locatable software that you can run in your simulation environment, but the parameters from the machine tool can be uploaded into the software module. Using the VNCK what we see are machining times that are much closer to the actual machining time and the actual cutter path generated by the CNC algorithms.

AMD: What type of new, innovative products can Siemens provide to help aerospace suppliers to further improve productivity and machine capabilities?
TIM: One thing that is just now being recognized and embraced in the supply chain is the collection of data, and transforming that into information that allows the supplier to quickly identify bottlenecks in the production system well before it becomes a critical issue for the product delivery schedule. Productivity improvement comes from having all of this data interconnected, and the data conditioned to provide information, reports or charts that allows supervision of the manufacturing process to make informed corrections or changes as the work parts are flowing through the system to make sure they hit their end delivery date. Another part of this that is very much related is product life-cycle management (PLM). Collecting the genealogy of every single part of a commercial aircraft is critical. The data needs to be stored in databases that are easily searched, and turned into information that you can use to make important decisions. We're now working on providing the feedback data out of our control systems for the "as-built" data. That really completes the loop – that as-built data coming out of the machines loops back and is stored in these massive databases. As the parts are being produced, the as-built data is going into the database and growing, so when the aircraft finally ships, they have complete data on the aircraft.

AMD: What developments can we expect to see in CNC technology in the next three to five years?
TIM: Given this PLM and the tightening of the process chain, it's going to be important to be able to collect this as-built data. The tendency will be the ever-tightening of the PLM loop. And the only other trend that I can see is more distributed drive systems, where as these machines get larger, you would be able to put the drives closer to where the motors are. Instead of having one huge magnetic cabinet with 20 drives in it, you'd have smaller cabinets around the machine.

AMD: Do you have any parting thoughts that you'd like to share with the readership of Aerospace Manufacturing and Design?
TIM: I think that we're heading into an extremely robust and challenging next five years, because there's a real confluence of things in the market that have come into play. A title wave is coming. You have F- 35s hitting rate in 2010 – 2011, you have 787 hitting rates, you have A350 coming online; you have all of the sectors of aerospace and defense ramping up at the same time. Put that against the backdrop of two things: the number of machine tool builders that are in existence today that can build 5-axis machines, and the reduction of capacity and lack of investment in the past three years in the supply chain. All of these things are creating the perfect storm, and it's going to be a challenge to get machine tools, programmers and operators, and will just get worse over the next few years. I see this as a real challenge for the industry to be able to cope with – this tremendous momentum that's going to be hitting the supply chain.