Originating Technology/NASA Contribution
Without the insulating protection of Earth’s atmosphere, orbiting space shuttles, space stations, and satellites are subject to thermal damage from radiation. This damage varies with different orbital parameters, solar activity, and the vehicle’s angle to the Sun, so these external surfaces must be designed to resist degradation and protect payloads (and crew) in these varying conditions.
Originating Technology/NASA Contribution
One of the basic nanotechnology structures, the carbon nanotube, is a graphite sheet one atomic layer thick that is wrapped on itself to create an extraordinarily thin, strong tube. Although carbon nanotubes were discovered more than 15 years ago, their use has been limited due to the complex, dangerous, and expensive methods for their production. This unwieldy process has made widespread application of single-walled carbon nanotubes (SWCNTs) cost-prohibitive up until now.
Goddard Space Flight Center has made a major step forward in limiting these drawbacks. While traditional manufacturing methods use a metal catalyst to form the tubes, NASA researchers pinpointed this step as the cause of many of the drawbacks that were impeding development of SWCNTs. NASA researchers, under the direction of Goddard’s Jeannette Benavides, discovered a simple, safe, and inexpensive method to create SWCNTs without the use of a metal catalyst. Benefits of this process include lowered manufacturing costs, a more robust product, and a simpler, safer process that produces a higher purity nanotube. NASA’s SWCNT manufacturing process eliminates the costs associated with the use of metal catalysts, including the cost of product purification.
The removal of the catalyst not only reduces cost, but results in high-quality, very pure SWCNTs. Because NASA’s process does not use a metal catalyst, no metal particles need to be removed from the final product. Eliminating the presence of metallic impurities results in the SWCNTs exhibiting higher degradation temperatures (650 °C rather than 500 °C) and eliminates damage to the SWCNTs by the purification process.
In addition to saving costs and creating a purer product, this new method also introduces features that make production simpler and safer. Unlike most current methods—which require expensive equipment (e.g., vacuum chamber), dangerous gasses, and extensive technical knowledge to operate—NASA’s simple SWCNT manufacturing process needs only an arc welder, a helium purge, an ice-water bath, and basic processing experience to begin production. This simple method also offers an increase in quantity. Whereas traditional catalytic arc discharge methods produce an “as prepared” sample with a 30 to 50 percent SWCNT yield, NASA’s method produces SWCNTs at an average yield of 70 percent.
Nanotailor Inc., a nanomaterials company specializing in SWCNTs, based in Austin, Texas, licensed Goddard’s unique SWCNT fabrication process with plans to make high-quality, low-cost SWCNTs available commercially.
“The nanotech industry is growing by more than 40 percent a year, but multi-walled carbon nanotubes have been the primary technology used. Single-walled technology just hasn’t taken off because of the cost,” notes Ramon Perales, president and chief executive officer of Nanotailor. “If we can get the cost down, we can be a step ahead and make higher quality nanotechnology more affordable.” Other companies that have licensed the process include Idaho Space Materials Inc., a start-up in Boise, and American GFM Corporation, in Chesapeake, Virginia.
With a license agreement in place, Nanotailor built and tested a prototype based on Goddard’s process. Device integrators and nanotechnology-based device companies are among Nanotailor’s first customers, though the company hopes to cater to a wide variety of industries and research organizations.
According to Dr. Reginald Parker, chief technical officer of Nanotailor, “Most industries using multi-walled tubes and technologies that require property improvement without a shift in weight will be able to benefit from this technology. A better product at a lower price will bring higher quality nanotechnology to biomaterials, advanced materials, space exploration, highway and building construction . . . the list seems endless as nanotubes have diverse and excellent properties.”
Nanotailor produces an optimized product based upon intellectual property licensed from NASA. Carbon nanotubes are being used in a wide variety of applications, and NASA’s improved production method will increase their prevalence in the following areas:
- Medicine: SWCNTs offer the opportunity for improvements in many medical technologies, including implantable defibrillators (pacemakers); portable/field equipment; implantable biosensors; improved hearing aids; electrochemical analysis of biological materials; composites for long-lasting bone and joint implants; delivery of medicines and other treatments at the cellular level.
- Microelectronics: SWCNTs offer low resistance, low mass density, and high stability for improved microcircuits, nanowires, and transistors for miniature electronics; and consumer products, including pagers, cell phones, laptop and hand-held computers, toys, power tools, and automotive components.
- Scanning force/tunneling microscopy: Probing tips made with SWCNTs last longer and perform better than conventional silicon tips, improving materials science research and development; production quality control of semiconductor materials and data storage media; and evaluation of biological samples.
- Materials: SWCNTs do not affect a polymer’s mechanical properties, allowing stress, transition, and thermal strain to be observed. SWCNTs also can be used to reinforce composites. Applications include dopants to create electrically conductive polymers; and easier monitoring of composites in critical applications (e.g., aircraft).
- Molecular containment: SWCNTs can be used to contain various elements, such as hydrogen for fuel cells and lithium boron hydrate for radiation shielding.
During September 2007, Nanotailor announced that its method for manufacturing high-quality carbon nanotubes was selected as a winner of the third annual Nanotech Briefs Nano 50 Awards. Jeannette Benavides, the inventor of the technology now retired from Goddard and serving as Nanotailor’s director of research, was recognized at the NASA Tech Briefs National Nano Engineering Conference in Boston, November 14 and 15, 2007.
“We are very pleased that our technology received a Nano 50 award,” commented Perales, “Nano 50 nominations are judged by a panel of nanotechnology experts of which the 50 technologies, products, and innovators with the highest scores are named winners. We are excited that our peers in the nanotechnology community believe that our technology has significantly impacted, or is expected to impact, the nanotechnology industry.”
Nanotech Briefs® is a registered trademark, and Nano 50™ is a
trademark of ABP International Inc.
Originating Technology/NASA Contribution
Polyimides are a class of polymers notable for chemical, wear, radiation, and temperature resistance, characteristics that have led to applications as diverse as aerospace engine housings and electronics packaging. Other applications include electronics, ranging from insulation for flexible cables to use as a high-temperature adhesive in the semiconductor industry. High-temperature polyimide carbon fiber composites are also used in non-loading structural components in aircrafts, weapon systems, and space vehicles. The appeal of polyimides is attributable to their unique combination of high-thermal stability, good chemical and solvent resistance, as well as excellent retention of mechanical properties at high temperature.
The polymerization of monomeric reactants (PMR) addition polyimide technology was developed in the mid-1970s at NASA’s Lewis Research Center (renamed Glenn Research Center in 1999). This technology used an alcohol solution of polyimide monomers to make “prepreg,” graphite or glass fiber bundles impregnated with polyimide resins, which could be thermally cured into composites with low voids, eliminating the difficulty of removing high-boiling solvents often used for condensation (step-polymerization) polyimides.
The initial PMR resin, known as PMR-15, is still commercially available and is used worldwide by the aerospace industry as the state-of-the-art resin for high-temperature polyimide composite applications; including engine bypass ducts, nozzle flaps, bushings, and bearings. PMR-15 can also be formualted into adhesives and coatings, and offers easy composite processing, excellent mechanical property retention for long-term use at temperatures up to 288 °C (550 °F), and is relatively inexpensive. As such, PMR-15 is widely regarded as a leading high-temperature polymer matrix composite for aircraft engine components.
However, PMR-15 is made from methylene dianiline (MDA), a known carcinogen and a liver toxin, and the Occupational Safety and Health Administration (OSHA) imposes strict regulations on the handling of MDA during the fabrication of PMR-15 composites. Recent concerns about the safety of workers involved in the manufacture and repair of PMR-15 components have led to the implementation of costly protective measures to limit worker exposure and ensure workplace safety.
Glenn researchers have continued to work on improving the properties and applicability of polyimides, with the ultimate goal of offering the aerospace, chemical, and automotive industries a lower toxicity alternative to PMR-15 that maintains similar processability, stability, and mechanical properties. The new polyimide developed by Dr. Kathy Chuang and Raymond Vannucci under NASA’s Advanced Subsonic Technology (AST) program, named DMBZ-15, replaces MDA with a noncoplanar diamine, 2,2´-dimethylbenzidine (DMBZ).
The DMBZ-15 composition has a glass transition temperature of 414 °C (777 °F). This constitutes an increase in use temperature of 55 °C (100 °F) over the state-of-the-art PMR-15 composites and enables the development of fiber-reinforced polymer matrix composites with use temperatures as high as 343 °C (650 °F). DMBZ-15 graphite fiber reinforced composites exhibit an operational temperature range up to 335 °C (635 °F) and good thermo-oxidative stability in aircraft engine or missile environments.
In 2002, Maverick Corporation, of Blue Ash, Ohio, licensed the DMBZ-15 technology.
In 2003, Chuang and Vannucci along with Maverick’s Dr. Robert Gray and Eric Collins received R&D Magazine’s 2003 “R&D 100” award recognizing
DMBZ-15 among the best 100 new inventions of the year. In 2004, the DMBZ-15 technology received a NASA Space Act Award.
DMBZ-15 bushings exhibit better wear resistance than state-of-the-art PMR-15. This ultrahigh-temperature material has a wide range of potential applications from aerospace (e.g., aircraft engine and airframe components, space transportation airframe and propulsion systems, and missiles) to bushings and bearings for non-aerospace applications (e.g., oil drilling, rolling mill). DMBZ-15 lightweight composites provide substantial weight savings and reduced machining costs compared to the same component made with more traditional metallic materials. Using solvent-assisted resin transfer molding, complex parts such as engine center vent tubes can be produced with braided reinforcement.
The DMBZ-15 polyimide has proven useful as a resin matrix with glass, quartz, and carbon fibers for lightweight, high-temperature composite applications similar to PMR-15 in aircraft engine components. Due to its higher temperature capability, it is especially suitable for use in missile applications, including fins, radon, and body components. Of particular interest to NASA, DMBZ-15 is well-suited to use as face sheets with honeycombs or thermal protection systems for reusable launch vehicles, which encounter elevated temperatures during launch and reentry. Other applications include use with chopped fibers to make bushings and bearings for engine or oil drilling components, and in high-temperature coating and ink applications. The light weight of DMBZ-15 polyimide composites invites use in secondary, non-load bearing aircraft engine components such as vent tubes, nozzle flaps and bushings, as well as for oil drilling components. Lightweight polymer composites also offer significant weight savings and subsequent improvements in fuel efficiency in aerospace propulsion and automotive applications.
Originating Technology/NASA Contribution
The Welding Institute (TWI), a nonprofit professional organization based out of the United Kingdom and devoted to the industry of joining materials, engineering, and allied technologies, developed a novel form of welding in the 1990s. Friction stir welding (FSW), the name under which it was patented, has been widely recognized as providing greatly improved weld properties over conventional fusion welds, and has been applied to manufacturing industries, including aircraft, marine, shipbuilding, including building decks for car ferries, trucking, railroading, large tank structure assembly, fuel tanks, radioactive waste container manufacturing, automotive hybrid aluminum, and the aerospace industry, where it is used to weld the aluminum external tank of the space shuttle.
FSW is a solid-state joining process—a combination of extruding and forging—ideal for use when the original metal characteristics must remain as unchanged as possible. During the FSW process, the pin of a cylindrical shouldered tool is slowly plunged into the joint between the two materials to be welded. The pin is then rotated at high speed, creating friction between the wear-resistant welding tool and the work piece. The resulting friction creates a plasticized shaft of material around the pin. As the pin moves forward in the joint, it “stirs,” or crushes, the plasticized material, creating a forged bond, or weld.
Although the FSW process is more reliable and maintains higher material properties than conventional welding methods, two major drawbacks with the initial design impacted the efficacy of the process: the requirement for different-length pin tools when welding materials of varying thickness, and the reliance on a pin tool that left an exit, or “keyhole,” at the end of the weld. The latter was a reliability concern, particularly when welding cylindrical items such as drums, pipes, and storage tanks, where the keyhole left by the retracted pin created a weakness in the weld and required an additional step to fill.
While exploring methods to improve the use of FSW in manufacturing, engineers at Marshall Space Flight Center (a licensee of TWI’s technology) created new pin tool technologies, including an automatic retractable pin tool, to address the method’s shortcomings. The tool uses a computer-controlled motor to automatically retract the pin into the shoulder of the tool at the end of the weld, preventing keyholes. The new technology addressed the limitations, and Marshall’s innovative retractable pin tool has since contributed to customized FSW that has been proven to provide routinely reliable welds.
The NASA engineers patented their developments and sought commercial licensees for their new innovations. MTS Systems Corporation, of Eden Prairie, Minnesota, discovered the NASA-developed technology and then signed a co-exclusive license agreement to commercialize Marshall’s auto-adjustable pin tool for a FSW patent in 2001. MTS is actively developing the FSW process, as well as new technologies to improve existing applications and to develop new ones. In addition, MTS has introduced the NASA technology to a wide variety of clients, in a wider variety of industries.
MTS worked with the NASA technology and developed a flexible system that enables advanced FSW applications for high-strength structural alloys. The product also offers the added bonuses of being cost-competitive, efficient, and, most importantly, versatile. Customers include automotive, aerospace, and other industries.
The FSW system available from MTS offers users many advantages over conventional welding, including the ability to work with diverse materials; a wide range of alloys, including previously unweldable aluminums and high-temperature materials, while minimizing material distortion. This flexibility makes it adaptable to virtually any application.
The MTS system provides durable joints, with two to three times the fatigue resistance of traditional joining technologies like fusion welding or riveting, and has no keyholes. Since the pin is retracted automatically at the end of the welding process, and the hole is sealed, the technique produces consistent bonds.
MTS has supplied a FSW production system to an aluminum rim manufacturer in Norway. The Volvo XC 90 SUV rim will be manufactured using a cast aluminum face with a spun formed aluminum sheet (hybrid rim). The two pieces are friction stir welded by internal and external weld joints. Jim Freeman, MTS welding engineer, commented that “the customer was using an addition procedure to eliminate the keyhole; by introducing the retractable pin tool technology the cycle time was reduced by 70 percent.”
FSW also lends itself to versatile welds, operating in all positions and able to create both straight welds and those requiring complex shapes. It even works with tapered-thickness weld joints, where the pin is able to maintain full penetration.
This technique, which does not require any consumables, is also advantageous, in that it does not create any environmental detriment, such as sparking, noise, or fumes. In addition, MTS’s FSW process is also safer than conventional welding, since it does not create hazards such as toxic welding fumes, radiation, high voltage, liquid metal spatter, or arcing.
MTS is currently engaged in several research projects to expand the usefulness of FSW. While the company does not normally engage in research initiatives, these specific projects will assist customers in developing uses for the FSW technique.
First, MTS and an aircraft manufacturing customer developed a pin control mode utilizing the retractable pin tool. Using a surface sensor, the pin is located relative to the part surface using pin position control, while the shoulder is in force control. This control mode allowed the customer to weld a 0.012-inch-thick butt joint using the retractable pin tool.
The company also participated in a dual-use science and technology agreement with the U.S. Navy’s Office of Naval Research to develop commercial and military applications for joining high-strength structural alloys. Program participants in addition to MTS include the University of South Carolina, General Dynamics Corporation’s Bath Iron Works and Electric Boat, Oak Ridge National Laboratory, and the Naval Surface Warfare Center–Carderock Division.
In another research initiative to advance the uses of FSW in industrial applications, MTS, along with several other recognized industrial leaders (e.g., NASA, Boeing, Lockheed Martin, Spirit Aerosystems, General Motors) is a cooperative partner at the Center for Friction Stir Processing (CFSP). This is a multi-institutional National Science Foundation Industry/University Cooperative Research Center founded in August 2004. Methods like the retractable pin tool are a critical part of the CFSP technology development roadmap.
Having licensed the NASA technology and undertaken several initiatives to improve the commercial FSW technique, MTS is now in a unique position to contribute back to the Space Program, as its product has been selected by Marshall for use in welding upper-stage cryogenic hardware for the Constellation Program’s
Originating Technology/NASA Contribution
Building on the success of the two rover geologists that arrived on Mars in January 2004, NASA’s next rover mission is being planned for travel to the Red Planet before the end of the decade. Twice as long and three times as heavy as the Mars Exploration Rovers, Spirit and Opportunity, the Mars Science Laboratory (MSL) will collect Martian soil and rock samples and analyze them for organic compounds and environmental conditions that could have supported microbial life.
MSL will be the first planetary mission to use precision landing techniques, steering itself toward the Martian surface similar to the way the space shuttle controls its entry through the Earth’s upper atmosphere. In this way, the spacecraft will fly to a desired location above the surface of Mars before deploying its parachute for the final landing. As currently envisioned, in the final minutes before touchdown, the spacecraft will activate its parachute and retrorockets before lowering the rover package to the surface on a tether (similar to the way a sky crane helicopter moves a large object). This landing method will enable the rover to land in an area 20 to 40 kilometers (12 to 24 miles) long, about the size of a small crater or wide canyon and three to five times smaller than previous landing zones on Mars. NASA plans to select a landing site on the basis of highly detailed images sent to Earth by the Mars Reconnaissance Orbiter, in addition to data from earlier missions.
Like the twin rovers now on the surface of Mars, the MSL will have six wheels, and cameras mounted on a mast. Unlike the twin rovers, it will carry a laser for vaporizing a thin layer from the surface of a rock to analyze the elemental composition of the underlying materials, and will be able to collect rock and soil samples and distribute them to onboard test chambers for chemical analysis. Its design includes a suite of scientific instruments for identifying organic compounds such as proteins, amino acids, and other acids and bases that attach themselves to carbon backbones and are essential to life as we know it. MSL will also identify features such as atmospheric gasses that may be associated with biological activity.
Using these tools, the MSL will examine Martian rocks and soils in greater detail than ever before to determine the geologic processes that formed them; study the Martian atmosphere; and determine the distribution and circulation of water and carbon dioxide, whether frozen, liquid, or gaseous.
The rover will carry a radioisotope power system that generates electricity from the heat of plutonium’s radioactive decay. This power source gives the mission an operating lifespan on Mars’ surface of a full Martian year (687 Earth days) or more while also providing significantly greater mobility and operational flexibility, enhanced science payload capability, and exploration of a much larger range of latitudes and altitudes than was possible on previous missions to Mars.
inXitu Inc., of Mountain View, California, a leader in portable X-ray diffraction/X-ray fluorescence (XRD/XRF) instrumentation, entered into a Phase II Small Business Innovation Research (SBIR) contract with Ames Research Center. The company specializes in developing technologies for the next generation of scientific instruments for materials analysis. It rapidly evolved throughout the SBIR Phase II research, starting as a sole proprietorship and growing to a 10-employee corporation. Critical findings from the research were applied to the CheMin instrument (an instrument with chemical and mineral identification capabilities included in the analytical laboratory of MSL), enabling robust operation of its sample handling system.
During this SBIR Phase II research, inXitu designed and built an automated sample handling system for planetary XRD instruments that enables quality analysis of coarse-grained materials (XRD analyzes the crystalline arrangements of atoms or molecules in solids). The sample handling method developed by inXitu allows direct analysis of materials obtained from drills or rock crushers, eliminating the need for the extensive sample preparation typically required for XRD analysis. Sample loading and removal have been automated without complex mechanisms and with a minimum of moving parts.
inXitu’s sample handling system could find a wide range of applications in research and industrial laboratories as a means to load powdered samples for analysis or process control. Potential industries include chemical, cement, inks, pharmaceutical, ceramics, and forensics. Additional applications include characterizing materials that cannot be ground to a fine size, such as explosives and research pharmaceuticals.
inXitu’s Terra product is the first truly portable XRD/XRF system designed specifically for rock and mineral analysis. XRD is the most definitive technique to accurately determine the mineralogical composition of rocks and soils. Phase identification is obtained by comparing the diffraction signature of a sample with a database of XRD mineral patterns. The addition of XRF informs on the nature of the chemical elements in the sample which allows easy screening during the phase identification process and can alleviate rare uncertainties.
Terra is the result of over a decade of research and development for space exploration instrumentation. Using a low-power X-ray source and energy dispersive
2-D charge coupled device (CCD) detector, XRD and XRF data are obtained with no moving parts, providing an unparalleled robustness. The system provides fast identification capabilities thanks to its optimized geometry and high-sensitivity detector. With the company’s patented sample handling system, only minimal sample preparation is required. Single minerals or simple mixtures can be identified after just a few minutes of integration.
Terra is built in a rugged, compact case for easy transport and operates autonomously via an embedded computer. In addition to a basic user interface on the instrument panel, a graphic user interface is available through a Wi-Fi link from any laptop or hand-held computer to control the instrument, preview live data, explore archive files, and download data.
Terra was first designed as a field geology/mineralogy instrument, but it can find a range of other applications where portability and fast analysis using XRD are required (mining, forensics, homeland security, etc.). Several Terra instruments are currently being used by NASA geologists to practice for the operational phase of the Mars Science Laboratory rover XRD instrument.
Originating Technology/NASA Contribution
A team of scientists at Glenn Research Center, operating under the Aeronautics Research Mission Directorate’s Aviation Safety and Fundamental Aeronautics programs, developed a series of technologies for testing aircraft engine combustion chambers. The team, led by electronics engineer Dr. Robert Okojie, designed a packaging technique and chip fabrication methods for creating silicon carbide (SiC) pressure sensors to improve jet engine testing. According to Okojie, the team was “working to develop pressure sensors that would be used to more accurately measure pressure inside jet engine combustion chambers where the temperature is very high.” Okojie’s team also understood that “due to their temperature limitations, conventional pressure sensors are usually kept further away from the sensed environment. As a result, measurement accuracy is generally compromised. In addition, vital dynamic information could be lost due to frequency attenuation. This new technology is meant to be inserted in close proximity with the sensed environment, thus eliminating these disadvantages.”
SiC-based pressure sensors fabricated using these NASA technologies can operate for over 130 hours at 600 °C. These durable chips are applicable in engine ground testing and short-duration flight test instrumentation. Kathy Needham, director of the Technology Transfer and Partnership Office at Glenn, explains, “We have been spearheading the use of silicon carbide in sensors for some time now—the material withstands high temperatures and allows measurements to be taken closer to the source. As an added advantage, the new sensors are less complex than current, similar sensors, reducing the likelihood of performance failure, allowing them to be manufactured relatively inexpensively, and reducing system maintenance needs.”
These factors also lend the technology to other uses, including commercial jet testing, deep well-drilling applications where pressure and temperature increase with drilling depth, and in automobile combustion chambers. As Okojie explains, “I see this technology being inserted in commercial jet engines and in deep wells while prospecting for oil. In commercial engine use, more accurate measurement of pressure would lead to improved engine safety by monitoring precursors of thermo-acoustic instability that leads to flame-out, efficient combustion of fuel and reduction of unwanted emission of hydrocarbons and nitrogen oxides. In deep well drilling, it would allow for longer term insertion into the wells, thereby significantly saving the cost of equipment maintenance and down time.”
To explore and develop these commercial uses, California’s San Juan Capistrano-based Endevco Corporation, a division of the Meggitt PLC group, licensed three patents covering the high-temperature, harsh-environment silicon carbide pressure sensors from Glenn. Collaboration between the two dates back to 2000, when, during combustion tests, Glenn used an Endevco silicon-based accelerometer as a benchmark device to validate its SiC accelerometer. The test results showed that the NASA device operated as well as the Endevco model, but the NASA-developed device had the added advantage of operating at much higher temperatures. This led to discussions between Endevco and Glenn about licensing opportunities to acquire Glenn’s SiC pressure and accelerometer sensor fabrication and packaging technologies.
Endevco met with the Glenn researchers on numerous occasions during the following years. After witnessing the advantages of the NASA technology first-hand, the company licensed the three NASA patents for commercial development with the caveat that Okojie would continue to work on the project and help the company overcome any outstanding technical issues. Okojie agrees with the importance of this arrangement. “The transfer of this technology to the commercial sector,” he says, “would extend the utilization of the products beyond the government (NASA, DOE, and DoD) to civil aviation, with derivative applications particularly in the efficient management of fuel combustion and the reduction of unwanted combustion byproducts.”
Building on years of already successful collaboration, the partnership now steers these novel technologies toward their envisioned commercial applications. “Endevco is the ideal partner to bring this NASA technology to market, since the company already has a proven track record in the field and is now willing to commit to making this new technology accessible to industry,” Needham elaborates. “The company,” she continues, “is planning a new product line, enabling this high-performance NASA technology to achieve widespread use.”
Founded in 1947, Endevco supports its customers with a global network of manufacturing and research facilities, sales offices, and field engineers, providing trusted solutions for the world’s most challenging measurement applications. In its more than 60 years of operation, Endevco has become a world leader in sensing solutions for demanding vibration, shock, and pressure applications. It was the company NASA trusted when it needed a benchmark device for its testing, and when the company saw that NASA had developed technologies that could improve the sensing field, it acted on the opportunity to license the cutting-edge know-how. NASA’s SiC technology is Endevco’s latest cutting-edge offering.
Originating Technology/NASA Contribution
Deformation resistance welding (DRW) is a revolutionary welding process—a new technique for joining metals—in an industry that has not changed significantly in decades. Developed by the Energy and Chassis Division of the Detroit-based Delphi Corporation (a spinoff company formed by General Motors in 1999), DRW can reduce the cycle time and fabrication cost for a variety of structures using hollow members. Applications include automotive, aerospace, structural, and fluid handling applications.
As the name implies, DRW applies the heat and force of resistance welding, with tooling designed to create the necessary deformation. The process bonds metals atomically and creates solid-state joints through the heating and deformation of the mating surfaces, and as such, requires no additional filler materials. Metal tubes are joined to solid metal forms, sheet metal, and other tubes, creating nearly instantaneous, full-strength, leak-tight welds that can be used to build lean structural assemblies. The leak-tight joints are capable of holding fluids or gasses under pressure and heat, and can have strength exceeding that of the parent metals. DRW promises increases in performance and design flexibility while helping to cut cost, investment, and weight.
In early studies, DRW demonstrated improved quality over conventional welding methods and novel joining capabilities. These studies caught NASA’s eye, and the Space Agency funded further development.
NASA’s Glenn Research Center, Delphi, and the Michigan Research Institute (MRI) entered into a research project to study the use of DRW in the construction and repair of stationary structures with multiple geometries and dissimilar materials, such as those NASA might use on the Moon or Mars. Delphi worked with the MRI (a not-for-profit organization created to speed the development of emerging technologies) to obtain an initial $2.17 million in the form of two grants, which were used to help develop new weld joint design configurations, perfect existing welding techniques, and equip a laboratory with technicians to test DRW. NASA analyzed the test results to understand how DRW could be used to weld different types of metal on Earth and in space, with an eye toward eventually using DRW to weld structures on the Moon and Mars.
Initial testing proved promising, and in 2005, Delphi created SpaceForm Inc., also of Detroit, to commercialize the DRW technology. NASA, encouraged by the testing, provided additional funding for a joint research partnership between Delphi, SpaceForm, and the Edison Welding Institute (EWI). Based in Columbus, Ohio, EWI is North America’s leading engineering and technology organization dedicated to welding and materials joining. EWI’s staff provides materials joining assistance, contract research, consulting services, and training to over 3,300 member company locations, representing world-class leaders in the aerospace, automotive, defense, energy, government, heavy manufacturing, medical, and electronics industries.
The EWI collaboration continued development of the DRW process and explored applications in ferrous and non-ferrous metals, dissimilar material joints, lean tubular structures, and concepts for future manufacturing cells. With EWI and NASA support, SpaceForm was able to advance DRW development toward production capabilities and narrow manufacturing parameters, making it a reliable, proven process. For these accomplishments, SpaceForm was awarded the Michigan Technology Leaders’ “Corporate Partnership Award” for 2006.
“We’re very pleased to have NASA’s continued support,” said Tim Forbes, director of commercialization and licensing at Delphi Technologies Inc., a subsidiary of Delphi Corporation. “The funded development projects with NASA have allowed us to gain a better understanding of the DRW joining process relative to a variety of materials, multiple joint configurations, joints with dissimilar materials, and the associated tooling and fixturing requirements. This work is supporting NASA objectives and is helping Delphi develop DRW for additional markets and customers.”
Current welding technologies are burdened by significant business and engineering challenges, including high costs of equipment and labor, heat-affected zones, limited automation, and inconsistent quality. DRW addresses each of those issues, while drastically reducing welding, manufacturing, and maintenance costs.
Manufacturers can expect lowered materials and capital costs and a significant reduction in welding cycle time. Additional advantages include localized heat application, and solid-state weld flexibility. The process can join dissimilar materials and shapes, is geometry-independent, and still automation friendly. Further, DRW is compliant (code case 2463) with the American Society of Mechanical Engineers and recognized for tube-to-tubesheet and heat exchanger manufacturing.
In addition to boasting a handful of manufacturing advantages, end-users will appreciate that the process eliminates weld leakage, that the weld is stronger than the parent metal, and that the method extends a product’s service life. The process also eliminates tube thinning and porosity.
“The list of potential applications quickly grew from an initial chassis/suspension application,” said Jayson D. Pankin, Delphi’s new venture creation specialist and co-founder of SpaceForm Inc. “Other potential automotive applications, which could benefit from tube construction, like roof frames, cross-car beams, exhaust systems, and chassis module assemblies were immediate opportunities. The technology also has potential applications in medical devices, bridges, water heaters, plumbing, and more. Virtually anything that could benefit from tube welding.”
DRW can reduce cycle time and cost in manufacturing an array of tubular structures. The technology can provide enhanced design flexibility in transportation and stationary applications, including motorcycles, recreational vehicles, bicycles, and wheelchairs, all while cutting cost investment in time and material.
Deformation resistance welding drastically reduces welding,
manufacturing, and maintenance costs.
NASA has invested considerable time and energy working with academia and private industry to develop new composite structures that are capable of standing up to the extreme conditions of space. Over time, such technology has evolved from traditional monocoque designs, in which the skin of a metal structure absorbs the majority of stress the structure is subjected to, to more complex, geometric designs that not only offer strength to counteract stress loads, but also add flexibility.
In June 2006, NASA scientists used extensive data transmitted from the Chandra X-ray Observatory deep space telescope to prove that up to 25 percent of the light illuminating the universe comes from the “massive crush of matter succumbing to the extreme gravity of black holes.”
In President Ronald Reagan’s 1984 State of the Union address, he announced plans for a U.S. space station, the equivalent of the Russian space station, Mir. This announcement set off a flurry of congressional funding debates, and it was not until 1988 that the President announced that a consensus had been reached and the project would go forward. The project was named “Space Station Freedom.”