Technology for Auto and Aero
Examining the crossover possibilities
By Jim Lorincz
The aerospace industry is engaged in a global search to forge links in its supply chain that in some respects resembles the automotive industry's tier configuration.
The aerospace industry's appetite for outsourcing precision-engineered parts and assemblies is being fed by demand that is reflected in rapidly growing backlogs of commercial aircraft. For its part, the automotive industry has attempted to expand its global sourcing through standardization of processes and products. The world car must still be designed and manufactured, preferably locally, to account for regional differences and tastes from country to country.
The aerospace industry has been seeking answers to questions similar to those raised by the automotive industry of the 1970s and the 1980s, according to United Grinding Technologies Inc. (UGT; Miamisburg, OH). UGT believes the answers to the following questions will dramatically shape supply chain configurations in the future and the choice of manufacturing processes.
- How can aerospace look at the entire value stream, beginning to end, and understand how manufacturing and logistics systems are going to be engaged so that they align with marketing projections and customer expectations?
- How can aerospace move from batch manufacturing with thousands of parts in the pipeline, to small lot sizes, frequent changeover, specific delivery windows, and no tangible inventory?
The answers lie in shifting manufacturing to lean flexible configurations, for example, away from traditional manufacturing centers comprising grinding, EDM, and milling departments to product cells that may include discrete processes, but where the objective is to manufacture a product complete without leaving the loop or cell. The solution is different today. Machine capacity is not necessarily created to grind or mill thousands of parts as fast as possible to sit in long queues awaiting further processing. Processing parts simply for inventory is waste.
It's the same thinking that motivated The Boeing Co. (Chicago) to initiate and implement a lean manufacturing program for its project to build the airplane wings and aft fuselage for the US Air Force's next-generation F/A 22 Raptor fighter/attack aircraft. Key to Boeing's lean effort on the Raptor program was reducing, or even eliminating, the aircraft maker's huge monument tooling, the extremely large fixtures or jigs used to build large aero structures like airplane wings that typically require hundreds of costly time-consuming crane moves.
The pace of transition to lean processing is all the more critical for the automotive industry. The cost of idling a transmission line due to process malfunction can be as high as $250,000 a minute, says UGT. Just as bad, although less visible, are product failures that raise warranty costs and the need for in-field replacements. The company says that manufacturers have to look up and down the automotive production line to find opportunities to combine processes like cleaning, polishing, and deburring matched to the level of operator skills and space limitations.
The commercial aircraft industry, defense aerospace sector, and general aviation are dealing with many of the issues that automotive manufacturers have faced in the last decade. The following are some areas that continue to be of interest to both:
- Lightweighting components is a critical consideration for both automotive and aerospace for one and the same reason: fuel efficiency in the face of spiking fuel costs and mandated by the government in the case of the auto industry. Lighter, stronger materials like aluminum, composites, titanium, and nickel-based alloys challenge machining.
- Automation in assembly has been a hallmark of the automotive industry, but more flexibility is being sought through use of machining centers and robots, especially at the tier level. Aerospace OEMs who produce markedly fewer completed units must find automation in drilling holes (literally by the tens and hundreds of thousands) and developing automated systems that can handle monumentally large structural components.
- Both automotive and aerospace have critical quality requirements that demand advanced measurement and inspection techniques. Shop-floor systems are making inroads in automotive plants; while the sheer size of aircraft structures challenges technological innovation in laser and radar-powered devices, as well as more traditional CMMs and hand-held versions.
- Both industries increasingly depend on their suppliers for engineering support as downsizing and right sizing have depleted the ranks of manufacturing engineering talent available to them.
Possible cross-over technology areas are reflected in the agenda of the Aerospace Automation Consortium for its continuing investigation:
- Integrated and automated airframe assembly line,
- Joining with adhesives,
- Laser radar GD&T inspection of machining composites,
- Robotic metrology and laser measurement systems, and
- Ensuring the volumetric compensation and accuracy of machine tools.
It wasn't too long ago that the aerospace industry adopted proven techniques that attempted to some degree or other to mimic the results of automotive assembly-line fabrication techniques for manufacturing airplanes.
At Lockheed Martin's mile-long hangar in Fort Worth, TX, automotive manufacturing and fabricating techniques are being adapted to building the F-35 Joint Strike Fighter. The aircraft are being lined up to be assembled from components, subassemblies, and modules that are delivered to the line.
At Broughton, UK, automation is speeding assembly of wing panels for the largest commerical aircraft, the Airbus 380. The 36.3-m long wings are being manufactured on four 165-m long automated wing-skin production lines using Electroimpact Inc. (Mukilteo, WA) E4380 riveting-bolting machines. About 180,000 holes are needed to produce a single Airbus 380 wing box and insert rivets and bolts. To get an idea of the scale involved, capacity is pegged at four pairs of wings a month.
Gaining an insight into solving a problem in one field and benefiting from the experience of another field, however esoteric the requirements, isn't that unusual. Flowserve Corp. (Irving, TX) was called upon by NASA's Stennis Space Center near Bay Saint Louis, MS, to provide high-pressure control valves of oxygen, hydrogen, and other propulsion propellants used in their rocket engine and component test facilities. The top-entry valves needed to be switched out and replaced for each test, a costly proposition.
Flowserve's application, design, and testing experience in the liquid natural gas, upstream oil and gas, and aerospace markets enabled it and a team of NASA engineers to generate a set of technical solutions that met NASA's requirements for high-pressure cryogenic, rocket propulsion tests. Stennis is the main propulsion testing center for NASA and is where the Space Shuttle main engines are tested and certified.
"High speed in machining is often talked about, but it's high productivity that is really wanted," says James Strohlberg, Walter-USA Inc. (Waukesha, WI). "I think the automotive people are maybe a little more focused on that than other industries. Some people tend to think that high speed automatically gives you high productivity which is not the case. A lot of it is the complete process, not just the high speed."
Strohlberg points out that there is more flexibility in machining systems to meet the different variations and smaller lot sizes for engines. "As more machining centers are integrated into the transfer lines, there is the opportunity to run faster because individual spindles provide flexibility to meet changed hole patterns simply by changing a program."
Collecting data and feeding it to a factory information system require power and versatility in a machine control. Siemens Energy and Automation Inc. (Elk Grove Village, IL), which is a supplier of sophisticated control systems to both aerospace and automotive manufacturers, provided the total motion control for 400 machine tools for a US automaker's 3.9L V-6 engine line.
The motion control package included cell controllers and many of the individual machine tool CNCs for the line, which comprised ten work cells, each containing six Ex-Cell-O machining systems and four Comau machining systems with Durr material handling as well as robotic buffers and other builders' equipment.
The machining systems with independent CNCs onboard transmit data to intermediate cell controllers. These cell controllers then feed production data to the host server. The cell controller is essentially a PC, which can monitor 80 machines, according to Siemens which also supplies the SINUMERIK 840D CNC, the predominant individual machine tool CNC chosen for this engine plant.
The E4380 wing-panel machine attaches stringers to the wing skin at the Airbus plant in Broughton, UK. Capacity is targeted at four pairs of wings a month.
"As global industrial companies have increasingly outsourced the manufacturing of their complex components, the gap between engineering and manufacturing has broadened dramatically," says Vykor Inc. (Renton, WA), a developer of software to provide aerospace and defense companies with decision-support analysis throughout the product lifecycle.
"This has resulted in a manufacturing knowledge gap, so companies do not have information on how the design decisions they make today will impact their supply chains in the future exposing them to higher costs and increased risk." The cost penalty can be as high as 25%, says Vykor.
Vykor numbers among its customers The Boeing Company, GE Aircraft Engines, GE Energy, Cessna, Lockheed Martin, and Vought Aircraft, among others. Please refer to the accompanying sidebar for Vykor's approach to enabling companies to develop and manage their supply chain.
Forging strong links in the supply chain
Vykor Inc. (Renton, WA) explains how the manufacturing knowledge gap affects global industrial companies who have increasingly outsourced the manufacturing of their complex components.
In the standard process used to bring products to market, engineering and manufacturing strategies are created at different points in the process. Engineering is completed at the front-end of the process while manufacturing strategies are created downstream, often at the supplier floor level after award. Three main sources drive the cost and risk penalty:
- Ineffective design producibility feedback,
- Non-integrated sourcing decisions,
- Inefficient manufacturing process deployment at suppliers.
Vykor's software analyzes how design and sourcing decision will impact the supply chain in the future. Its technology is used to model the detailed manufacturing strategies for knowledge capture, work transfer, streamlined planning, improved communications, and cost analytics.
Vykor also provides a database of detailed supplier capability information, including shop size, capacity, capital equipment assets, core competencies, material preferences, and business factors like location and disadvantaged business status.
By capturing and quantifying the manufacturing strategy and analyzing it against supplier capabilities, Vykor's software can answer what a part will cost, why the parts costs what it does, how to ensure the cost is achieved, and who in the supply chain has the capabilities and experience to build to the cost.
This article was first published in the October 2006 edition of Manufacturing Engineering magazine.