Material technology is reducing the use of precious metals and developing alloys, bringing sensors closer to rocket engines, reducing costs and improving safety.
According to Morgan Stanley, the aerospace industry is developing rapidly and is expected to be worth US$1.1 trillion by 2040, up from US$384 million in 2017. Between the possibilities of space exploration, satellite communications, and space tourism, more applications require the ability to get into orbit or farther away.
However, the huge costs involved in vehicle launches may slow this growth. The complexity of space travel leads to excessive costs. NASA estimates that the average cost of each launch of the space shuttle is $450 million. Endeavour is the last orbiter in NASA's space shuttle program. It cost $1.7 billion and underwent multiple overhauls between its first mission in 1992 and its retirement in 2011. In addition, more manned flights make safety a huge issue for exploration and tourism, requiring well-designed and proven systems.
Brazing is a long-term technology that connects two metals by heating and melting a filler alloy combined with two metals. It can play a role in improving safety and cost.
Gold, palladium and other precious metals — the brazing materials that sent humans to the moon and supported most of the early space exploration efforts — are becoming increasingly scarce, pushing up commodity prices. Engineers are usually reluctant to give up years of research and development data that show that the alloy is tested and reliable.
Non-precious metal alloys made of nickel, chromium and cobalt have been successful in aviation applications, and researchers are working to make them suitable for orbits and beyond.
Morgan Advanced Materials' two brazing alloys, RI-46 and RI-49, were designed by NASA and used in the main engine RS25 of the space shuttle. Morgan engineers developed RI-46 to replace the old gold/nickel Nioro brazing alloy. Reducing the content of gold and replacing it with copper and manganese significantly reduces the density of brazing alloys and significantly reduces weight while maintaining temperature performance from -240°C to 700°C (-400°F to 1,292°F) . NASA plans to continue using these alloys in its Space Launch System (SLS), a vehicle planned for manned missions to Mars.
The brazing alloy in space equipment allows the sensor to be installed as close as possible to the engine to measure and monitor the output and feed the data back to the operator. Mission control and crew can then accurately read and measure fuel efficiency, temperature, gas flow data and output, and monitor fire detection or abnormal conditions. If these sensors are too far from the engine, the data readings will become inaccurate, which may affect the mission.
At the end of 2018, after the rocket launch failed, the two astronauts had to suspend their flight to the International Space Station (ISS). The Soyuz spacecraft began to malfunction after 119 seconds of flight. The first problem was reported by the crew, not by the mission control center. The crew described the feeling of weightlessness, which indicated that there was a problem at that stage of the flight. They aborted, ejected their space capsule from the rocket, and returned to Earth safely.
Although the cause of the failure is still to be determined, this situation should not happen. Any problems should be resolved by the mission control center, rather than relying on the judgement of the crew.
The challenge is that some sensors are made of ceramics because they need to be resistant to corrosion and high temperatures, usually up to 950°C (1,742°F). These ceramic sensors then need to be connected to the metal parts of the engine, which requires different brazing alloys.
Active alloys can combine metals and ceramics or ceramics and ceramics.
Morgan designed Incusil-ABA and Ticusil for such applications about 40 years ago, and these applications are still in use today. The new alloy under development should be able to withstand higher temperatures.
Morgan Advanced Materials' Specialty Metals and Joining Center of Excellence (CoE) in Hayward, California enables the materials company to provide alloys for specific applications, run tests to test materials, brazing cycles, and fixtures. Engineers can study the entire operation, from powder atomization to preform manufacturing, to brazing testing.
One of the current developments is Flexicore, which is a technology that transforms traditional brittle alloys (such as AMS4777) into a flexible wire form. Flexicore will allow users to choose nickel-based alloys to replace precious metals, thereby reducing costs and reducing the weight of gold in future space applications.
Third Dimension's smart GapGun measuring equipment reduced surface inspection time by 90%.
Manual inspection of aircraft parts using depth gauges can be very time-consuming, which has prompted many manufacturers to choose faster and more automated processes. Therefore, when military helicopter manufacturer AgustaWestland needed to shorten the inspection time of Merlin helicopter panels, it chose GapGun measurement equipment.
AgustaWestland operators use Third Dimension's handheld GapGun laser measurement system to quickly perform detailed contour measurements on the depth of scratches on helicopter panels and aircraft gearbox components. Maintenance, repair and overhaul (MRO) inspection time for internal and external composite panels has been reduced by nearly 90%.
"Compared with manual measuring tools, they wanted something that would reduce the burden on the operator and provide some traceability," explains Paul Waterfall, Product Manager of Third Dimension.
Before using the equipment; if the operator finds a scratch, the employee will remove the panel, fix a new panel with bolts, and then transport the damaged panel to the metrology laboratory to measure whether it passes. The panel will then return to join the spare parts group until it is needed. This process can take up to eight months, because they wait until a batch of panels are to be shipped, which incurs huge costs.
"The device has the quality of a metrology laboratory, but has a handheld function. It can be taken anywhere," Waterfall said. "If the helicopter lands and someone says,'OK, I'm worried about this,' you can take the GapGun to the helicopter, take the measurement in a few minutes, and then leave. You don't need to remove and replace the panel."
GapGun brings to the workshop the accuracy and precision normally only found in metrology laboratories. Within 20 minutes, the device determines the size profile of the part by taking a series of photos of the surface of the part. The operator can then determine whether the depth of the scratch is within the required 0.15 mm limit and verify whether the part needs repair or replacement.
"The data is also immediately transferred to the backend so that you can keep a complete record and traceability by the serial number, operator," Waterfall said. "It really helps to understand the manufacturing process you are using. You can easily find the difference between the different contact points."
Third Dimension, located in Bristol, UK, develops and manufactures non-contact precision contour measurement solutions.
Founded in 1995, Third Dimension provides metering equipment and services to well-known companies in the global aerospace, automotive and energy fields. Third Dimension also provides a wide range of application accessories and support, calibration and training services.
Laser Components specializes in the development, manufacturing and sales of components and services for the laser and optoelectronic industries.
The company has been serving customers since 1982 and has sales branches in five different countries. Laser Components has been manufacturing in-house products since 1986, with production facilities in Germany, Canada, and the United States.
AgustaWestland is a British helicopter design and manufacturing company and a wholly-owned subsidiary of Leonardo SpA, headquartered in Rome, Italy. Leonardo is an Italian multinational company specializing in aerospace, defense and security. The AgustaWestland Merlin helicopter was first manufactured in 2000.
GapGun is a non-contact automatic laser measurement system that can assess the dimensional integrity or contour of a part without touching the surface. The device’s graphical user interface (GUI) guides the user through the entire process with minimal training.
GapGun uses laser triangulation technology to collect measurement values. It projects the laser element line laser or fringe onto the surface of the part to determine the measurable features.
"When we adopted Laser Components' lasers, we got a more uniform, consistent and reliable product, thus speeding up our manufacturing process," Waterfall said. "It provides a very consistent focus."
At the same time, the integrated camera system takes images of static laser stripes. Once the system measures the angle between the camera and the laser projection, the algorithm calculates the size of the surface scanned by the laser and the camera. This data generates a digital copy of the surface.
The software uses image processing to generate a point cloud and converts the contour image into a series of points with extrapolated feature shapes. These points allow the system to analyze the surface under test. Since the laser is a structured light, the measurement data is highly reliable and can be used as a stable light source for data analysis.
The measured profile features of the part include angles, radii, edge breaks and scratches. The measured values are then recorded for statistical process control and traceability, and transmitted to the computer, enabling the operator to identify any possible errors in the production line in real time.
The camera view of the laser projected onto the surface enables the operator to see gaps or changes in the pattern. For example, the scratch may be shiny or green or brown. Operators measuring different surfaces need to control laser intensity and camera sensors. The VChange sensor interface of GapGun Pro allows operators to quickly remove, exchange and reconnect sensors. The dynamic range of the sensor extends from extremely bright surfaces (such as soft chrome) to the darkest paint on carbon surfaces. Changing the laser intensity and controlling the camera can achieve the necessary accuracy when measuring various challenging surface finishes. The adjustable laser cap of the device can shorten or split the laser line to measure complex features.
SHS type cage ball LM guide provides high speed and high precision. Each row of balls is arranged at an angle of 45°, so that SHS can be used in all directions.
THK cage technology provides smooth and quiet movement, using a synthetic resin cage with curvature to support each ball and separate it from the next. The space between the rolling elements can retain grease and serve as a lubrication system to achieve long-term maintenance-free operation. Other benefits include improved speed and accuracy, reduced noise levels, low dust generation and long life.
The high-performance processing module and controller enable the four-slide process monitoring and sensors to synchronize and accurately operate. The configurable VC1 touch screen controller facilitates programmable cam changes and fast machine settings.
The productivity of 4-slide-NC is as high as 250 parts per minute.
The integrated recording and data measurement of the VC1 central machine controller supports operator performance to ensure production reliability. The machine safety standard includes door safety switches to prevent contact with the shaft.
The Touch Panel 600 operator interface equipment includes high-tech screens and high-quality visualization. Cortex A9 multi-core processor provides fast operating speed. Onboard security includes a built-in firewall and virtual private network (VPN) to help users deal with cyber attacks. All panels have a future-oriented Linux operating system and support HTML5 technology.
Each touch panel has an energy-saving standby function, an integrated sensor can automatically adjust the brightness, and an easy-to-install design.
ProPath automated workstation cranes’ lightweight enclosed rail aluminum (ETA) rail system and semi-automated or fully automated smart material handling solutions can improve safety, productivity and uptime. ETA track system can be used as runway and bridge track.
Two automation configurations can be used for different levels of control, including wireless communication, positioning components, and diagnosis and analysis. Magnetek's semi-automatic and fully automatic control systems enable efficient manufacturing processes.
There are multiple options for the crane’s Z-axis motion and control panel, as well as options for enhanced communication, positioning and safety.
Physical security and network security are needed to protect the avionics of modern small airplanes and helicopters.
Low visibility conditions force pilots of small aircraft to operate in accordance with the instrument flight plan, navigating and maintaining aircraft control only by instrument readings. It doesn't matter-she has been trained in this area. Suddenly, the plane hit an obstacle that shouldn't be a factor. The instrument gave false readings and guided the pilot directly to the target.
This sounds like an action movie-a similar scene was staged in Die Hard 2 when the plane crashed after the villain modified the instrument landing system. In fact, a network security vulnerability that allows instruments and avionics to communicate was recently discovered in the controller area network (CAN bus), indicating that this situation is technically possible. An attacker with unsupervised physical access to the aircraft may destroy the data it displays to the pilot or change its flight path.
Fortunately, this vulnerability was not exploited-it was only exposed by cybersecurity researchers. The risk is so serious that the Cyber Security and Infrastructure Security Agency (CISA) of the U.S. Department of Homeland Security issued an information alert in July 2019. The CAN bus raises important questions for the aerospace industry and highlights the core concept of a sound cybersecurity strategy.
The CAN bus is basically a wire system that allows instruments and avionics in modern small airplanes and helicopters to share information without a central computer. On airplanes, the CAN bus is usually located in a compartment that is easy to maintain.
In a test conducted by the cybersecurity company Rapid7, a small device plugged into the CAN bus can change the displayed information, such as altitude, airspeed, and engine readings. It can even control or disable the autopilot.
Hackers need expertise and a few minutes to access the aircraft, which requires special planning and knowledge, especially because the aircraft is stored in a secure facility. Although this is not something that ordinary hackers can do, the possibility of damage is very high, and the worst result is more spectacular than hacking into automobile automation systems.
So far, the only way to fix this vulnerability is to put the aircraft in a locked state. A savvy pilot may notice and compensate for false data appearing on the instrument. For example, there is almost always an old-fashioned, unpowered magnetic compass on an airplane, which will not be affected by hacking of avionics connected to the CAN bus. Many pilots also fly with additional navigation equipment that is not connected to the Internet, such as an iPad running Foreflight.
When flying in instrument conditions, properly trained pilots may notice differences between onboard avionics and non-networked auxiliary systems. However, sometimes the margin of error is very small during instrument flight, especially when making precision instrument approaches at airports with low visibility.
In addition to finance, the aerospace manufacturing industry is now the industry with the highest level of cybersecurity in the US NIST 800-171 strict and comprehensive cybersecurity guidelines, which came into effect on December 31, 2017. This guidance applies to any manufacturer's supply chain that handles controlled non-confidential information (CUI) anywhere in the federal government. NIST 800-171 covers more than a dozen standards on how to configure the network, how to store and track data, and how employees gain access.
Although the deadline has long passed, many smaller manufacturers are still accelerating their pace, driven by the compliance requirements of the large companies they supply. In addition, these guidelines are very complex and thorough, and it takes months to achieve compliance.
As aerospace manufacturers pay more and more attention to protecting their environment and data, CAN bus vulnerabilities remind people to put network security first when designing software and network systems. Engineers must put themselves in the shoes of hackers, imagine how a given system can be used, now and suppose in the future. With the regular exposure of new Internet of Things (IoT) exploits, it is easy to see the dangers of designing an open CAN bus system (dating back to the 1980s), even if there is no obvious direct threat. The best results can be achieved when security becomes part of the design specification rather than an afterthought.
The CAN bus vulnerability illustrates the concept that data must be protected physically and electronically. The NIST 800-171 Cyber Security Guide covers the physical security of manufacturing facilities. On the other hand, the physical security of airplanes, airports, and hangars is the only factor preventing CAN bus vulnerabilities from being exploited. If the CAN bus has a robust authentication mechanism that only communicates with good devices, we would not have this discussion.
An effective network security strategy has multiple levels. Physical security is often overlooked because some companies fail to protect access to server cabinets or monitoring facilities. Although the aerospace industry has done a good job in this regard, any single-layer cyber security system is doomed to fail in the end. A more secure environment restricts physical access to its network and logically controls which devices can connect to it.
In the long term, manufacturers of instruments and avionics connected to the CAN bus may need to add safety features that restrict how components interact. The challenge will be to find a way to make this change before a catastrophic cyber attack occurs. Since the CAN bus vulnerability was announced in July, there has not been much talk about designing components to compensate for it. The idea seems to be that the plane is safely stored, the pilot has been alerted, and everything should be fine. I hope so. In terms of network security, hope that the best result is often the worst.
About the author: Jonathan Stone is an instrument-rated commercial helicopter pilot and chief technology officer for Kelser Corp., an IT consulting company in Connecticut. You can contact him at jstone@kelsercorp.com
Wear-A form of wear caused by metal surfaces sliding against each other, such as all the bolts and fasteners that hold the aircraft together.
Worn fasteners that get stuck or experience fatigue fracture can cause potentially catastrophic effects, so aircraft manufacturers must deal with this threat. Not everyone in the manufacturing industry is familiar with wear and tear, except for those who absolutely must know: designers and engineers. As wear and tear pose a serious threat to the quality and safety of expensive and critical equipment, employees in executive management, operations, and procurement departments should also study this phenomenon wisely.
In wear, excessive friction between two moving metal surfaces can cause mechanical wear, and when a load compresses the surfaces together, it tears the material and transfers it between the surfaces.
Standard stainless steel bolts and fasteners are prone to wear under certain conditions. When pressure and friction cause the thread of the bolt to jam the thread of the nut or threaded hole, standard fasteners may experience thread wear. Severe wear called cold welding can cause the two surfaces to fuse together, and the joint cannot be removed without cutting the bolt or splitting the nut.
The consequences of Garin should not be underestimated. Worn fasteners may not reach the necessary preload-especially in dynamic loads. This jeopardizes the task of the fastener to securely fasten the two surfaces together, which is complicated because the application may involve hundreds or even thousands of stainless steel fasteners.
If there are key fasteners in the rotating parts of chemical pumps, rotor blades or propeller winches, the joints are likely to experience fatigue fracture, and customers need expensive maintenance and downtime. In the worst case, fatigue fracture of critical fasteners may cause accidents or injuries. Worn fasteners are also more susceptible to corrosion, which will eventually lead to breakage.
Due to its atomic structure, certain types of stainless steel are more prone to wear. Due to increased strength and reduced ductility, cold-formed, strain-hardened stainless steel has excellent wear resistance.
The tight fastener fit reduces the risk of wear by minimizing movement and friction. High-quality threads have fewer surface deviations, which can rub together and cause wear.
Lubrication allows materials to slide against each other without causing friction. Some leading manufacturers of high-quality fasteners use custom waxes to ensure the best coefficient of friction. Anti-seize and anti-wear lubricants also help reduce wear.
Bolts with dented or damaged threads can significantly increase the chance of wear. Check all fasteners for damage during transportation. Dirty bolts with chips in the threads also greatly increase the risk of wear-so only clean bolts should be used.
Most stainless steels are sensitive to high temperatures, so tightening bolts slowly can reduce friction and heat that can cause wear. Avoid using power tools that can cause excessive friction and overheating. Calculate each application to determine which tools can be used.
In addition to reducing the risk of wear, high-quality fasteners:
In the aerospace industry, if the thread jams before sufficient torque is obtained, a catastrophic failure may occur. However, wear can be overcome even in the most challenging applications—especially by choosing high-quality stainless steel fasteners.
Fasteners such as Bumax 88 have high molybdenum content, which makes the joint more robust, reliable and corrosion resistant.
High-quality fasteners may look similar to standard stainless steel fasteners, but the superior material properties can make the wear completely different. Explain to your fastener supplier exactly how to use fasteners to ensure optimal wear resistance. High-quality stainless steel fasteners often provide other characteristics essential in many key fastener applications, including corrosion resistance and high tensile strength.
About the author: Patrik Lundström Törnquist is the managing director of Bumax, and Anders So¨derman is the company's technical director. Their contact details are anders.soderman@bufab.com and patrik.tornquist@bufab.com.
Sample cutting of printed circuit boards (PCB) improves inspection quality and efficiency.
Printed circuit boards (PCBs) need to operate reliably in harsh aerospace environments to withstand extreme temperatures, humidity, vibration, and in some cases, solar radiation.
Therefore, the manufacturing process must be accurate and reliable to provide an industry standard for 15 to 20 years of trouble-free operation for electronic products.
Ensuring the reliability of the PCB starts from its manufacturing and design, following every step of the strict quality control procedure.
PCB provides the basic building blocks of electronic devices. They are composed of alternating layers of material to provide insulating coatings and conductive paths. Circuit board manufacturers can use less durable materials to make cheaper PCBs, but higher quality circuit boards are mainly composed of fiberglass, such as FR4. The manufacturer manufactures multilayer boards in sequence. Processing can be expensive and adds value to the component. It is not advisable to find problems in the later stages of the production process, so quality control inspections must be carried out quickly and effectively at critical stages. Test specimens and parts are usually manufactured within the PCB to achieve this reliability.
The test card allows the manufacturer to analyze the PCB in the quality assurance laboratory. The sample is subject to the same manufacturing process and sequence as the PCB, and the specific characteristics existing on the entire circuit board can be evaluated before the manufacturer installs other components. With the same quality and defects as PCB, the coupon will show any quality issues.
Even without the components that are ultimately mounted on it, the circuit board is a complex part. The plate usually contains fillers, such as silica. It can also be made of aluminum, which manufacturers use as a dielectric for high-frequency boards.
Some manufacturers design test samples that can be easily pressed out of the circuit board to ensure that they can be removed without damaging the entire circuit board. If this is not done, it must be removed using an appropriate cutting tool, which is a critical step given the brittle material of the circuit board.
Coupons can check for issues such as bare board quality, etching definition, layer registration, plating quality or solder mask definition. They can also monitor the assembly process of surface mount technology (SMT) and traditional plated through hole (PTH) assembly types-cutting and riveting quality, solder paste printing quality, insertion accuracy, reflow/flow soldering quality, and assembly cleanliness.
Manufacturing the sample at the same time as the main PCB will produce the same impedance, which depends on the size and electrical characteristics of the PCB.
The main board inspection focuses on the thickness of copper plating and the width of the component mounting through-holes. A scanning electron microscope (SEM) inspects the holes to determine if they meet specifications. If the hole is too wide, the laboratory will reject the plate.
It may be contaminated during the copper plating process. In addition, the integrity of the surface coating of the circuit board must be tested. If the packaging is not sufficient, the circuit board will oxidize, thereby shortening the service life of the component. The IPC-222 standard defines the test specimen design requirements, and the IPC-601 standard determines the minimum and maximum dimensions of all internal and external features, including laminate, plating, foil, holes, and spaces.
For inspections, the laboratory needs to remove the test piece from the PCB without damaging the structure of the test piece. The part must be cut to a specific size while preventing the board from cracking. Since many boards contain brittle materials, this can be challenging.
Some laboratories use a hand saw, which may be inaccurate and may damage the specimen or circuit board. Cutting these coupons is more than just cutting them off the PCB. There are many inspection areas, and cutting damage can make quality inspection impossible.
In addition, there must be some margin between the edge of the circuit board and where the copper coating starts. Finally, do not cut the edge of the board during cutting to avoid secondary damage.
Grinding and precision cutting machines and dicing saws can support metallographic testing. The sample preparation for PCB microstructure inspection starts with quality cutting. Choosing the right slicing blade and precision cutting saw can limit the number of steps required to analyze the sample, thereby saving time.
The correct sample slicing technique depends on the thickness, size and silica composition of the circuit board. According to the hardness of the plate, technicians can choose a cutting blade with a low density of diamond cutting points to reduce damage to hard and brittle materials.
The latest developments in precision cutting saws are improving the accuracy and efficiency of cutting specimens, and can provide the versatility required by various PCBs.
In order to improve efficiency, the semi-automatic slicing saw control device can easily position the sample to minimize the set-up time, and can be adapted to various sample sizes. These controls can realize fast cutting parameter setting. The protective or smart cutting function limits the cutting load of the precision saw, ensuring consistent quality.
Accuracy is crucial. Precision PCB requires precise positioning, higher reproducibility and minimal sample distortion. In order to obtain higher precision, advanced devices can be fine-tuned after clamping.
Automatic continuous cutting—the ability to accurately cut parallel lines without re-clamping—increases efficiency, reduces operator variability, and ensures high-quality specimens. Using a dedicated precision cutter, laboratory technicians can cut 10 to 20 samples per hour with minimal deformation. As a large number of circuit boards enter the quality assurance laboratory from the factory floor, these systems allow the facility to process more samples to keep the production line running.
Inspection of PCB test specimens with plated through holes or through holes requires metallographic preparation of the specimen. This process requires the specimen to be installed in plastic to protect the specimen, and then ground and polished to the center of the feature of interest.
Due to the continued miniaturization of electronic equipment, these functions may be very small-but targeting centers is essential for accurate quality control inspections. In high-volume laboratories where speed and quality are equally important, this can be achieved using test specimens of specific sizes.
The specimen can be fixed in a precision target grinding jig, which uses a reference pin to hold the specimen in place. The diamond stop in the fixture then allows grinding to features of interest with accuracy up to 0.004" (0.102mm).
For quality assurance laboratories that process a variety of samples, precision saws can cut all kinds of materials from PCB to rubber, nickel superalloy and carbon fiber. The saw manufacturer can guide you to determine which cutting blade matches the type of sheet or other material you are inspecting.
The ability of quality laboratories to keep up with inspections should not slow down. Hurrying through this process should not compromise quality control or threaten the reliability of aircraft using PCBs.
About the author: Nanu Vishora is a materials engineer at Buehler, an Illinois Tool Works (ITW) company. You can contact him at info@buehler.com.