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Aircraft potable (drinking) water systems haven’t changed significantly in the last half-century. These systems consist of cylindrical water tanks pressurized by bleed air from the jet engines, with insulated stainless steel distribution lines. What has changed recently is the increase in the possibility of aircraft picking up contaminated drinking water at foreign and domestic stops. Customer awareness of these problems has also changed - to the point where having reliable drinking water is now a competitive issue among airlines. Old style potable water systems that are used on modern aircraft are high maintenance and exacerbate the growth of microbes because the water is static much of the time. The integrity of some pressurized water tanks are also a concern after years of use. Cost-effective mechanical and biological solutions exist that can significantly reduce the amount of chemicals added and provide good potable water.

Flex Track Systems are seeing increased usage in aerospace applications for joining large assemblies, such as fuselage sections. Previous systems were limited to work pieces that allowed the tracks to follow a gentle radius of curvature, limiting the locations where the system could be used. This paper describes a new 5-Axis Flex Track System developed to expand the usage of the systems, allowing them to process work pieces containing complex and irregular contours. Processing complex contours is accomplished through the addition of A and B axes providing normalization in multiple directions. These new systems are configured with the latest multi-function process capabilities allowing drilling, hole quality measurement, and temporary or permanent fastener installation.

The Automated Spar Assembly Tool (ASAT II) at the Everett, Washington, 777 Boeing manufacturing facility could be the largest automated fastening cell in the commercial aircraft industry. Based on the success of the ASAT I, Boeing's 767 spar assembly tool, the 285-foot long ASAT II cell was needed to accurately position and fasten the major spar components (chords and web), then locate and fasten over 100 components (ribposts and stiffeners) to assemble the 777 forward and rear wing spars. From its inception in 1990 to the first drilled hole in January 1993 and through two years of spar production, the more advanced ASAT II has proven to be a greater success than even its 767 ASAT I predecessor. This massive automated fastening system consistently provides accurate hole preparation, inspection, and installation of three fastener types ranging from 3/16 inches to 7/16 inches in diameter.

Wing panels for Boeing's new 777 airplane are assembled using fastening machines called Wing Fastener Systems (WFS). Compared to the wing riveting machines currently used to squeeze rivets for other airplane models, the 777 WFS provides significantly more features in that it also installs two part fasteners, collects process data for Statistical Process Control analysis, plus other functions. Historically, new operators for wing riveting machines have needed six months of on-the-job training to achieve basic qualification. Because of the increased functionality of the 777 WFS, an eight to nine month O.J.T. requirement was anticipated. Training requirements were further compounded by our need for up to thirty qualified operators in a relatively short time frame and a maintenance staff thoroughly trained in the new control architecture. Boeing's response to this challenge was to use simulation methods similar to those used to train pilots for our customer airlines.

Fabrication and assembly of the majority of control surfaces for Boeing’s 777X airplane is completed at the Boeing Defense, Space and Security (BDS) site in St. Louis, Missouri. The former 777 airplane has been revamped to compete with affordability goals and contentious markets requiring cost-effective production technologies with high maturity and reliability. With tens of thousands of fasteners per shipset, the tasks of drilling, countersinking, hole inspection, and temporary fastener installation are automated. Additionally and wherever possible, blueprint fasteners are automatically installed. Initial production is supported by four (4) Electroimpact robotic systems embedded into a pulse-line production system requiring strategic processing and safeguarding solutions to manage several key layout, build and product flow constraints.

In large scale industries attempts are continuously being made to automate assembly processes to not only increase productivity but also alleviate non-ergonomic tasks. However this is not always technologically possible due to specific joining challenges and the high number of special-purpose parts. For the riveting process, for example, semi-automated approaches represent an alternative to optimizing aircraft assembly and to reduce the exposure of workers to non-ergonomic conditions entailed by performing repetitive tasks. In [1], a semi-automated solution is proposed for the riveting process of assembling the section barrel of the aft section to its pressure bulkhead. The method introduced a dynamic task sharing strategy between human and robot that implements interaction possibilities to establish a communication between a human and a robot in Human-Robot-collaboration fashion.

Corrosion problems associated with using titanium fasteners to assemble aluminum airframe structures are reviewed. Data are presented describing the effectiveness of metallic platings and an aluminum filled organic based coating on fasteners to render the titanium-aluminum electrochemical couple inoperative. The aluminum enriched organic coating known as Hi-Kote 1 is shown to be more effective in minimizing corrosive attack on aluminum airframe structure in both saline and acidic environments. The effectiveness of Hi-Kote 1 in corrosion-fatigue tests of fastened aluminum structure is also reported.

In a fastening system when there is a small misalignment of the holes, the holes are enlarged to align the axes and a next size fastener is used to fit the joint. But when the misalignment is large then the enlargement need to be proportionally large. In this case a bushing is press fit onto the hole to handle the fastening. If we press fit a bushing, it generates residual stresses in the panel. These residual stresses reduce the damage life of the components on which the bushings were press fit. In the aircraft engine nacelle components the damage life is very critical in various failure conditions such as fan blade out condition, wind milling and bird strike. It increases the flight time in these events. Here four different case studies were considered to study the damage life of the aircraft components made of Aluminum or composite material.

The fastener analysis for an airframe panels under random cyclic loading conditions were analyzed with various elaborate solutions. But here a simple technique is proposed to analyze the problem and prove the necessity for a design solution. It is shown that the misfit in the fastener system reduces the load capacity of the joint due to the lack of contact or reduced contact. This reduced contact also produces various stress concentration at the contact zones. In the cyclic loading environment this reduced load capacity and increased stress concentration produces elastic plastic deformation around the contact locations and at the same time a crack develops and propagates beyond the fastener system. This creates a load leak transparent to the fastener system. Thus the misfit fastener systems have a higher probability of aging than the fit fasteners. With the proof in hand various design patterns were proposed to improve the fatigue characters under varying types of loading conditions.

The fastener analysis for an airframe panels under random cyclic loading conditions were analyzed with various elaborate solutions. But here a simple technique is proposed to analyze the problem. The fastener system in any structure could develop crack at the edges of the hole or at the fastener head rim location and propagate further between bolts. The sub- layer crack and micro cracks are hard to locate visually. Here a solution method is presented to detect the crack for various types of fastener conditions such as the fully contacted fastening, partial contact and no-contact condition. This is one of the useful tools to check the health of the fastening systems. Part I of this paper shows the necessity for a fix that arise in the initial misfit conditions. They also show the fastening efficiency for all the different condition. Here we would like to address the detection of a crack in any of the above fastening conditions.

An automated drilling and fastening system is under development at the GEMCOR Engineering Corporation for wing manufacture on a new commercial airframe program. It is the first time that cold-working and hole inspection have been integrated into an automated fastener installation system. Numerical control and monitoring of all process parameters have been integrated in the system to achieve the greatest degree of accuracy and repeatability in fastener installation and to provide real-time, in-process statistical quality control. An integral component of the system is a capacitance probe used to measure the diameter and profile of drilled holes. Measurement information obtained with the hole probe is used to monitor the drilling process and predict tooling wear. This paper briefly discusses fastener hole requirements and the effects of hole quality on fatigue life. An overview of the capacitance measurement technique is also presented.

McDonnell Douglas Aircraft in St. Louis, MO manufacturers various transport and fighter military aircraft such as the C-17 and the F/A-18. With shrinking military budgets and increased competition, market forces demand high quality parts at lower cost and shorter lead times. Currently, a large number of different fastener types which include both solid rivets and interference bolts are used to fasten these assemblies. The majority of these fasteners are installed by hand or by using manually operated C-Frame riveters. MDA engineers recognized that in order to reach their goals they would be required to rethink all phases of the assembly system, which includes fastener selection, part fixturing and fastener installation methods. Phase 1 of this program is to identify and to develop fastener installation processes which will provide the required flexibility. The EMR fastening process provides this flexibility.

The need for a flexible and automated seam riveting system has opened the door for a new approach to machine design. The Flexible Lateral Seam Riveting system (FLSR) proposed by Gemcor will be able to automatically, under CNC and tracer control, rivet both lateral and radial joints without the use of dedicated and fixed machine track systems. The FLSR system is adaptable to a wide range of part diameters and configurations with lengths up to 10m (394 inches). Applications include aircraft fuselage sections as well as any other circular section which is assembled with rivets or other standard aerospace fastener systems including interference fit type.

Over the last few years, many aircraft production lines have seen their production rate increase. In some cases, to avoid bottlenecks in the assembly lines, the productivity of processes needs to be improved while keeping existing machine-tools. In this context, the case of drilling machine-tools tends to require particular attention, especially when multi-material parts are drilled. In such instances, the Vibration Assisted Drilling (VAD) process can be a way to improve productivity and reliability while keeping quality standards. This article presents a case of a drilling/countersinking process for stainless steel and titanium stack parts. Firstly, the article assesses the feasibility and benefits of using Vibration Assisted Drilling and Countersinking with the current cutting-tools. Secondly, it studies the consequences of introducing a new tool holder in the process, which combines the V.A.D. function, a new declutching function and the ability to control countersink depth.

Extensive experimental data was collected for CBN surface grinding of M2 tool steel to determine the relative grinding performance of three different vitrified CBN abrasive grit sizes. The results define the relationships between the grinding forces, the material removal rate and the resulting specific energy, while providing an evaluation of the ground surface characteristics including surface finish, microstructure, hardness and residual stress. The interaction of grinding process inputs including wheel grit size, workpiece velocity and depth of cut are considered, and a series of single factor tests and a 23 factorial test are conducted. The grinding forces increase linearly with increasing material removal rate for the range of parameters tested.

A new type of temporary fastener fulfills the requirement of reduced specific loads applied to composite structures. With that the danger of delamination especially at sloped surfaces is under control and limited. It is also insensitive to contamination and provides reduced maintenance of the clamping means. For disassembly a controlled screwing process guaranties that structure and panel will not be damaged.

In this work we have proposed an interesting clamping solution of V-band which has an important industrial impact by reducing the cost and assembly process as well compare to the traditional V-band. The design what we are focusing for is applied for all size of turbochargers which helps to connect the hot components such as manifold and turbine housing. The cost for V-band is mainly from T-bolt. It is made from special stainless steel which represents 50% of the total cost. In this work it is proposed a new V-band joint by changing bolt clamping status from tension to compression. From tension to compression we change the bolt material from high cost steel to low cost steel. The new total cost is reduced by 40%. The prototype is made and performed in static tests including anti-rotating torque test and salt spray test. The new joint meets the design requirements at static condition. Further work will focus on the dynamic qualification and at high temperature as well.

Accurate and fast positioning of large aircraft component is of great importance for Automated Alignment System. The Ball joint is a widely-used mechanical device connecting the aircraft component and positioners. However, there are some shortcomings for the device in man-machine engineering, such as the entry state of the ball-head still needs to be confirmed by the workers and then switched to the locking state manually. To solve above problems, a new positioning mechanism is present in this paper, which consists of a ball-head and a ball-socket. The new device is equipped with a monocular vision system, in which a calibrated industrial camera is used to collect the images of the ball-head. And then, the 3-D coordinate of the ball-head center is calculated by a designed algorithm, guiding the positioner to capture the ball-head. Once the ball-head gets into the ball-socket, the pneumatic system will drive the pistons to move to the specified location.

The carbothermal reduction of ilmenite and iron- bearing silicates are important in the manufacture of steel and perhaps for manufacture of oxygen on the moon. Oxygen recovery from ilmenite and iron silicates is of interest because of the abundance of such minerals on the lunar surface and the relative ease of their reductions. A novel carbothermal reduction process is developed for the reduction of these minerals. This presentation summarizes an experimental study of the carbothermal reduction of ilmenite and iron-bearing silicates at temperatures between 850°C and 1100°C. Extremely high reduction rates are observed and investigated for carbothermal reduction of ilmenite by using deposited carbon. These results are compared to previous kinetics studies with regards to the different activation energy values reported.