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Technical Paper

C919 Trailing Edge Assembly Interchangeable Tooling

2019-09-16
2019-01-1880
Traditional Trailing Edge (TE) assembly that utilise fixtures for accurate positioning of aircraft (a/c) parts do not allow for removal of specific tooling from the fixtures to travel with the TE, post assembly. Instead, the tooling that positions all the primary a/c assembly datums generally utilise precision pins of various sizes that index and clamp the a/c ribs. Often it is difficult to remove the pins post assembly before the spar can be taken out of the fixture. Use of hammers is common place to hit pins out of holes which is less than ideal considering the a/c parts can be fragile and the tooling is precision set. Also, the Main Assembly Fixture (MAJ) that will receive the TE will inevitably need to relocate some if not all the primary a/c ribs and therefore will most likely be subject to some amount of persuasion.
Technical Paper

Improved Briles Rivet Forming Using High-Speed Force Feedback and Improved Die Geometry

2019-03-19
2019-01-1377
Electroimpact and Kawasaki Heavy Industries (KHI) have produced a new riveting process for the forming of Briles type rivets in Boeing 777 and 777X fuselage assemblies. The Briles rivet is typically used for fuselage assembly and is unique in that it has a self-sealing head. Unlike conventional headed rivets such as the NAS1079, this fastener does not require aircraft sealant under the head to be fluid tight. This unique fastener makes for a difficult fastening process due to the fact that interference must be maintained between the hole and fastener shank, as well as along the sides of the fastener head. Common issues with the formed fasteners include gapping under the fastener head and along the shank of the fastener. Electroimpact has employed a host of different technologies to combat these issues with Briles fastening. First, Electroimpact’s patented “Air Gap” system allows the machine to confirm that the head of the rivet is fully seated in the countersink prior to forming.
Technical Paper

Automatic Drilling and Fastening System for Large Aircraft Doors

2019-03-19
2019-01-1346
Electroimpact has developed a system for drilling and fastening of cargo door structures which efficiently addresses many of the manufacturing challenges that such parts present. Challenges to door automation include 1) the presence of an inner skin that must be processed, in addition to the outer skin, and 2) a stiff frame structure, which makes the clamping and drilling processes that are typical to automated fastening machines very unforgiving of any errors in workpiece positioning. In this case, the manufacturing cell was to be installed in an existing facility with very limited ceiling height, further complicating the system and process design. New methods were devised to solve these problems, and the solutions found will likely have utility in future applications.
Journal Article

Collaborative Robotic Fastening Using Stereo Machine Vision

2019-03-19
2019-01-1374
With typically over 2.3 million parts, attached with over 3 million fasteners, it may be surprising to learn that approximately two out of every three fasteners on a twin aisle aircraft are fastened by hand. In addition the fasteners are often installed in locations designed for strength and not necessarily ergonomics. These facts lead to vast opportunities to automate this tedious and repetitive task. The solution outlined in this paper utilizes the latest machine vision and robotics techniques to solve these unique challenges. Stereo machine vision techniques find the fastener on the interior of an aerospace structure and calculate the 6DOF (Degrees of Freedom) location in less than 500ms. Once the fastener is located, sealed, and inspected for bead width and gaps, a nut or collar is then installed. Force feedback capabilities of a collaborative robot are used to prevent part damage and ensure the nut or collar are properly located on the fastener.
Technical Paper

Automated Riveting of C-130J Aft Fuselage Panels

2017-09-19
2017-01-2075
Electroimpact and Lockheed Martin have developed an automated drilling and fastening system for C-130J aft fuselage panels. Numerous design and manufacturing challenges were addressed to incorporate the system into Lockheed Martin’s existing manufacturing paradigm and to adapt Electroimpact’s existing line of riveting machines for manufacture of these legacy aircraft parts. Challenges to automation included design of a very long yet sufficiently rigid and lightweight offset riveting anvil for fastening around deep circumferential frames, automated feeding of very short, “square” rivets in which the length is similar to the head diameter, creation of part programs and simulation models for legacy parts with no existing 3d manufacturing data, and crash protection for the aircraft part from machine collisions, given the uncertainties inherent in the model and the unique geometry of the aircraft parts.
Technical Paper

Fully Automated Off-Line Cartridge Filling Station

2017-09-19
2017-01-2100
A fully automated off-line cartridge filling station has been commissioned to support the new Boeing SAL production cell. The filing station uses automated fastener feed technology that is typically found on the machines themselves. Incorporating this technology off-line in place of the traditional manual handling processes extends the benefits of automation beyond the main manufacturing cell. A single operator is able to keep up with the demand of eight production fastening machines while maintaining the highest levels of accuracy and quality. Additional benefits to this application of automation include reduction of the operators exposure to risks associated with manual handling and repetitive tasks.
Technical Paper

Lights Out Cell Automatic Tool Change Solution for Nut and Collar Anvils with Integrated Fastener Feed Hardware

2017-09-19
2017-01-2097
Automated collar and nut installation requires complex hardware on the wet side of the spar or wing panel. Wet side automatic tool changers are becoming common but an operator is often required to connect electrical, pneumatic and fastener feed system components. This is unacceptable in a lights-out cell, and any fully automatic solution must be reliable while satisfying demanding design requirements. Figure 1 Wet side anvil for nut installation. The 737 Spar Assembly Line (SAL) is a new lights-out machine cell at the Boeing factory in Renton, Washington. The SAL machines are equipped with a unique fully automatic tool changer (ATC). The wet side ATC interface is designed to automatically connect conventional as well as more unique services such as fastener feed. The fastener feed ATC module, called the “spinner,” rotates with the machine’s wet side rotary axis (C axis). It consists of a stack of rotors that rotate inside of a stationary annulus.
Technical Paper

EMR with High Reliability for Retrofit of E4100 Riveting Gantry Machines

2017-09-19
2017-01-2099
Electroimpact has retrofitted two E4100 riveting gantry machines and two more are in process. These machines use the EMR (Electromagnetic Riveter) riveting process for the installation of slug rivets. We have improved the skin side EMR to provide fast and reliable results: reliability improved by eliminating a weekly shutdown of the machine. In paper 2015-01-2515 we showed the slug rivet injector using a Synchronized Parallel Gripper that provides good results over multiple rivet diameters. This injector is mounted to the skin side EMR so that the rivet injection can be done at any position of the shuttle table. The EMR is a challenging application for the fingers due to shock and vibration. In previous designs, fingers would occasionally be thrown out of the slots. To provide reliable results we redesigned the fingers retainer to capture the finger in a slotted plastic block which slides along the outside diameter of the driver bearing.
Technical Paper

High-Accuracy Articulated Mobile Robots

2017-09-19
2017-01-2095
The advent of accuracy improvement methods in robotic arm manipulators have allowed these systems to penetrate applications previously reserved for larger, robustly supported machine architectures. A benefit of the relative reduced size of serial-link robotic systems is the potential for their mobilization throughout a manufacturing environment. However, the mobility of a system offers unique challenges in maintaining the high-accuracy requirement of many applications, particularly in aerospace manufacturing. Discussed herein are several aspects of mechanical design, control, and accuracy calibration required to retain accurate motion over large volumes when utilizing mobile articulated robotic systems. A number of mobile robot system architectures and their measured static accuracy performance are provided in support of the particular methods discussed.
Technical Paper

AFP Automated Inspection System Performance and Expectations

2017-09-19
2017-01-2150
In AFP manufacturing systems, manually inspection of parts consumes a large portion of total production time and is susceptible to missing defects. The aerospace industry is responding to this inefficiency by focusing on the development of automated inspection systems. The first generation of automated inspection systems is now entering production. This paper reviews the performance of the first generation system and discusses reasonable expectations. Estimates of automated inspection time will be made, and it will be shown that the automated solution enables a detailed statistical analysis of manufactured part quality and provides the data necessary for statistical process control. Data collection allows for a reduction in rework because not all errors need to be corrected. Expectations will be set for the accuracy for both ply boundary and overlap/gap measurements. The time and resource cost of development and integration will also be discussed.
Technical Paper

Magnetic Safety Base for Automated Riveting and Bolting

2016-09-27
2016-01-2087
There is an ever-present risk for the lower ram on a riveting machine to suffer a damaging collision with aircraft parts during automated fastening processes. The risk intensifies when part frame geometry is complex and fastener locations are close to part features. The lower anvil must be led through an obstructive environment, and there is need for crash protection during side-to-side and lowering motion. An additional requirement is stripping bolt collars using the downward motion of the lower ram, which can require as much as 2500 pounds of pulling force. The retention force on the lower anvil would therefore need to be in excess of 2500 pounds. To accomplish this a CNC controlled electromagnetic interface was developed, capable of pulling with 0-3400 pounds. This electromagnetic safety base releases when impact occurs from the sides or during downward motion (5 sided crash protection), and it retains all riveting and bolting functionality.
Technical Paper

Coated Rivet Dies: A Dramatic Improvement in Rivet Interference Profile

2016-09-27
2016-01-2084
Successfully riveting aerospace fatigue-rated structure (for instance, wing panels) requires achieving rivet interference between a minimum and a maximum value in a number of locations along the shank of the rivet. In unbalanced structure, where the skin is much thicker than the stringer, this can be particularly challenging, as achieving minimum interference at the exit of the skin (D2) can often be a problem without exceeding the maximum interference at the exit of the stringer (D4). Softer base materials and harder, higher-strength rivets can compound the problem, while standard manufacturing variations in hardness of part and rivet materials can cause repeatability issues in the process. This paper presents a solution that has been successfully implemented on a production commercial aircraft. The application of a special coating on the stringer side die dramatically reduces interference at the exit of the stringer, which in some instances resulted in a reduction of over 38%.
Technical Paper

High Speed Fastener Inspection

2016-09-27
2016-01-2145
Inspection of fasteners prior to installation is critical to the quality of aerospace parts. Fasteners must be inspected for length/grip and diameter at a minimum. Inspecting the fasteners mechanically just prior to insertion can cause additional cycle time loss if inspection cannot be performed at the same time as other operations. To decrease fastener inspection times and to ensure fastener cartridges contain the expected fastener a system was devised to measure the fastener as it travels down the fastener feed tube. This process could be adapted to inspection of fasteners being fed to the process head of a running machine eliminating the mechanical inspection requirement and thus decreasing cycle time.
Journal Article

Plate Cartridge Compact Flexible Automatic Feed System

2016-09-27
2016-01-2080
The newest generation of automated fastening machines require a feed system that is smaller, more flexible, and faster than any currently available. The feed system must be compact enough to fit on a robot base, yet have a capacity large enough to support unmanned production for hours. A large variety of fasteners must be supported and the entire system must be reloaded or reconfigured in minutes to match the next work piece being assembled by the machine. When requested by the part program, the correct fastener must be released directly and immediately into the feed tube to minimize cycle time. This paper describes a new “plate cartridge” feed system developed to meet these needs.
Journal Article

Automatic Temporary Fastener Installation System for Wingbox Assembly

2016-09-27
2016-01-2085
The automation cycle time of wing assembly can be shortened by the automated installation of single-sided temporary fasteners to provide temporary part clamping and doweling during panel drilling. Feeding these fasteners poses problems due to their complexity in design and overall heavy weight. In the past, Electroimpact has remotely fed these fasteners by blowing them through pneumatic tubing. This technique has resulted in occasional damage to fasteners during delivery and a complex feed system that requires frequent maintenance. Due to these issues, Electroimpact has developed a new fully automated single-sided temporary fastening system for installation of the LISI Clampberry fasteners in wing panels for the C919 wing factory in Yanliang, China. The feed system stores fasteners in gravity-fed cartridges on the end effector near the point of installation.
Journal Article

Automated In-Process Inspection System for AFP Machines

2015-09-15
2015-01-2608
In many existing AFP cells manual inspection of composite plies accounts for a large percentage of production time. Next generation AFP cells can require an even greater inspection burden. The industry is rapidly developing technologies to reduce inspection time and to replace manual inspection with automated solutions. Electroimpact is delivering a solution that integrates multiple technologies to combat inspection challenges. The approach integrates laser projectors, cameras, and laser profilometers in a comprehensive user interface that greatly reduces the burden on inspectors and decreases overall run time. This paper discusses the implementation of each technology and the user interface that ties the data together and presents it to the inspector.
Journal Article

System for Recirculation of Mobile Tooling

2015-09-15
2015-01-2494
Aircraft assembly systems which require tooling or machinery to pulse or move between multiple positions within a factory can be positioned with high repeatability without high performance foundations or sweeping out large areas of floorspace. An example shows a system of large left and right-hand frames which are positioned at 3 sequential manufacturing steps and then recirculated to the start of production via a central return aisle. The frames are 41 ton actual weight and are 72′ long, similar to a rail car. The system achieves rectangular motion for the recirculation path. The supporting and moving system incorporates low-cost rail in a floor with minimal preparation and simple to use controls. The system is also easily reconfigured if the manufacturing system needs to be altered to meet rate or flow requirements.
Journal Article

Integrated Ball-Screw Based Upset Process for Index Head Rivets Used in Wing Panel Assembly

2015-09-15
2015-01-2491
A new high speed forming process for fatigue rated index head rivets used in wing panel assembly using ball-screw based servo squeeze actuation has been developed. The new process is achieved using a combination of force and position control and is capable of forming to 40,000 lbs at rates of up to 200,000 lbs/second whilst holding the part location to within +/− 10 thousandths of an inch. Multi-axis riveting machines often have positioning axes that are also used for fastener upset. It is often the case that while a CNC is used for positioning control, another secondary controller is used to perform the fastener upset. In the new process, it has been possible to combine the control of the upset process with the machine CNC, thus eliminating any separate controllers. The fastener upset force profile is controlled throughout the forming of the rivet by using a closed loop force control system that has a load cell mounted directly behind the stringer side forming tool.
Technical Paper

Use of Synchronized Parallel Grippers in Fastener Injection Systems

2015-09-15
2015-01-2515
A new style of rivet injector is in production use on a variety of fastening machines used by major aircraft manufacturers. In this injector the opposing sides of the rivet guide blocks are attached to the arms of a parallel gripper. We have implemented the parallel gripper in both vertical axis and horizontal axis riveting applications. It is equally effective in both orientations. We have implemented the parallel gripper rivet injector on headed rivets, threaded bolts, ribbed swage bolts and unheaded (slug) rivets.
Technical Paper

Robotic Drilling and Countersinking on Highly Curved Surfaces

2015-09-15
2015-01-2517
Electroimpact has developed a novel method for accurately drilling and countersinking holes on highly convex parts using an articulated arm robotic drilling system. Highly curved parts, such as the leading edge of an aircraft wing, present numerous challenges when attempting to drill normal to the part surface and produce tight tolerance countersinks. Electroipmact's Accurate Robot technology allows extremely accurate positioning of the tool point and the spindle vector orientation. However, due to the high local curvature of the part, even a small positional deviation of the tool point can result in a significantly different normal vector than expected from an NC program. An off-normal hole will result in an out of tolerance countersink and a non-flush fastener.
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