Search Results

Developing the most advanced wing panel assembly line for very high production rates required an innovative and integrated solution, relying on the latest technologies in the industry. Looking back at over five decades of commercial aircraft assembly, a clear and singular vision of a fully integrated solution was defined for the new panel production line. The execution was to be focused on co-developing the automation, tooling, material handling and facilities while limiting the number of parties involved. Using the latest technologies in all these areas also required a development plan, which included pre-qualification at all stages of the system development. Planning this large scale project included goals not only for the final solution but for the development and implementation stages as well. The results: Design/build philosophy reduced project time and the number of teams involved. This allowed for easier communication and extended development time well into the project.

Design and production of an assembly system for a major aircraft component is a complex undertaking, which demands a large-scale system view. Electroimpact has completed a turnkey assembly line for producing the wing, flap, and aileron structures for the COMAC C919 aircraft in Xi’an, China. The project scope includes assembly process design, material handling design, equipment design, manufacture, installation, and first article production support. Inputs to the assembly line are individual component parts and small subassemblies. The assembly line output is a structurally completed set of wing box, flaps, and ailerons, for delivery to the Final Assembly Line in Shanghai. There is a trend toward defining an assembly line procurement contract by production capacity, versus a list of components, which implies that an equipment supplier must become an owner of production processes.

Starting in 2003 Electroimpact began development on a comprehensive kinematic and compensation software package for machines with large envelopes. The software was first implemented on Electroimpact's Automatic Fiber Placement (AFP) equipment. Implementation became almost universal by 2005. By systematically collecting tracker measurements at various machine poses and then using this software to optimize the kinematic parameters of the machine, we are able to reliably achieve machine positional accuracy of approximately 2x the uncertainty of the measurements themselves. The goal of this paper is to document some of the features of this system and show the results of compensation in the hope that this method of machine compensation or similar versions will become mainstream.

A new portable floor drilling machine, the 767AFDE, has been designed with a focus on increased reach and speed, ease-of-use, and minimal weight. A 13-foot wide drilling span allows consolidation of 767 section 45 floor drilling into a single swath. A custom CNC interface simplifies machine operations and troubleshooting. Four servo-driven, air-cooled spindles allow high rate drilling through titanium and aluminum. An aluminum space frame optimized for high stiffness/weight ratio allows high speed operation while minimizing aircraft floor deflection. Bridge track tooling interfaces between the machine and the aircraft grid. A vacuum system, offline calibration plate, and transportation dolly complete the cell.

Electroimpact revisited a piece of automation history this year. In 1989, Electroimpact delivered its first ever Automated Electromagnetic Riveting and Assembly Cell or A.E.R.A.C. to Textron Aero Structures, now Vought Aircraft Industries. These machines produce upper wing panels for Airbus A330/340 aircraft. They were the precursor to the Low Voltage Electromagnetic Riveters or LVER's producing wing panels for Airbus single isle, A340 and A380 programs in Broughton, Wales, UK. In 2009, Electroimpact delivered two next generation AERAC machines to Vought Aircraft Industries. A significant design challenge was to hold the moving mass for the entire machine under 5220 kg without sacrificing performance of the LVER. These machines employ several new technologies to achieve this including Electroimpact's latest generation rivet injector, an integrated headstone load cell, and GE Fanuc's customer board.

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%.

Figure 1 Global 7000 Business Jet. Photo credit: Robert Backus. The customer’s assembly philosophy demanded a fully integrated flexible pulse line for their Final Assembly Line (FAL) to assemble their new business jets. Major challenges included devising a new material handling system, developing capable positioners and achieving accurate joins while accommodating two different aircraft variants (requiring a “flexible” system). An additional requirement was that the system be easily relocated to allow for future growth and reorganization. Crane based material handling presents certain collision and handover risks, and also present a logistics challenge as cranes can become overworked. Automated guided vehicles can be used to move large parts such as wings, but the resulting sweep path becomes a major operational limitation. The customer did not like the trade-offs for either of these approaches.

A frame-clip riveting end effector has been developed for installing 3.97mm (5/32) and 4.6mm (3/16) universal head aluminum rivets. The end effector can be mounted on the end of a robot arm. The end effector provides 35.6 kNt (8000 lbs) of rivet upset. Rivets can be installed fifteen millimeters from the IML. The clearance allowed to rivet centerline is 150 millimeters. The riveting process features a unique style of rivet fingers for the universal head rivet. These fingers allow the rivet to be brought in with the ram. This differentiates from some styles of frame-clip end effectors in which the rivet is blown into the hole. The paper shows the technical components of the end effector in sequence: the pneumatic clamp, rivet insert and upset. The end effector will be used for riveting shear ties to frames on the IML of fuselage panels.

The use of a narrow profile posts or Skinny Fixture increases build speed and flexibility while improving quality of aluminum aircraft panels fastened in one-up assembly cells. Aluminum aircraft panels are made up of an outer skin and a series of stringers. The components must be held in accurate relative positions while preliminary fasteners are installed. By using narrow fixture posts in conjunction with deep drop stringer side machine tools, the fastening machine can apply fasteners at tighter initial spacing. The spacing is gained by providing clearances that allows the centerline of the fastening system to work closer to the post than previously achieved with deep fixture posts and short stringer side tooling. At one time the standard process was to hold the parts in manual tack cells and after tacking the panels are moved to a separate automated fastening cell. One-up assembly fixtures improve the process by reducing manual processes while minimizing component handling.

Electroimpact has developed an automated solution for installing OSI-Bolts on the HStab for Boeing's 787-9 aircraft. This solution utilizes Electroimpact's existing accurate robotic system together with new hardware designed specifically for OSI-Bolts. In addition to automated drilling and fastener installation, this system performs numerous quality checks to insure the installed fastener meets engineering requirements. Before installing the fastener, the system measures actual stack thickness and the length of the fastener to ensure that the proper grip is installed. Torque and angle feedback are recorded during installation which can be used determine if the fastener was installed correctly. The system will also automatically shave the small protuberance on the fastener head left by the broken off fastener stem, which is inherent to the OSI-Bolt. Figure 1 Cell Overview

Aircraft manufacturers are seeking automated systems capable of positioning large structural components with a positional accuracy of ±0.25mm. Previous attempts at using coordinated arm robots for such applications have suffered from the use of low accuracy robots and minimal systems integration. Electroimpact has designed a system that leverages our patented Accurate Robot technology to create an extensively automated and comprehensively integrated process driven by the native airplane component geometry. The predominantly auto-generated programs are executed on a single Siemens CNC that controls two Electroimpact-enhanced Kuka 6 axis robots. This paper documents the system design including the specification, applicable technologies, descriptions of system components, and the comprehensive system integration. The first use of this system will be the accurate assembly of production empennage panels for the Boeing 777X, 787 and 777 airplanes.

A new automated production system for installation of Lightweight Groove Proportioned (LGP) and Hi-Lock bolts in wing panels has been implemented in the Boeing 737 wing manufacturing facility in Renton, Washington. The system inserts LGP and Hi-Lok bolts into interference holes using a ball screw mechanical squeeze process supported by a back side rod-locked pneumatic clamp cylinder. Collars are fed and loaded onto a swage die retaining pin, and swaging is performed through ball screw mechanical squeeze. Offset and straight collar tools allow the machine to access 99.9% of fasteners in 3/16″, ¼″ and 5/16″ diameters. Collar stripping forces are resolved using a dynamic ram inertial technique that reduces the pull on the work piece. Titanium TN nuts are fed and loaded into a socket with a retaining spring, and installed on Hi-Loks Hi-Lok with a Bosch right angle nut runner.

Accurate measurement of countersinks in curved parts has always been a challenge. The countersink reference is defined relative to the panel surface which includes some degree of curvature. This curvature thus makes accurate measurements very difficult using both contact and 2D non-contact measurements. By utilizing structured light 3D vision technologies, the ability to very accurately measure a countersink to small tolerances can be achieved. By knowing the pose of the camera and projector, triangulation can be used to calculate the distance to thousands of points on the panel and countersink surface. The plane of the panel is then calculated using Random Sample Consensus (RANSAC) method from the dataset of points which can be adjusted to account for panel curvatures. The countersink is then found using a similar RANSAC method.

Electroimpact has developed a second generation of mobile robots with several improvements over the first generation. The frame has been revised from a welded steel tube to a welded steel plate structure, making the dynamic response of the structure stiffer and reducing load deflections while maintaining the same weight. The deflections of the frame have been optimized to simplify position compensation. The caster mechanism is very compact, offers greater mounting flexibility, and improved maneuverability. The mechanism uses a pneumatic airbag for both lifting and suspension. The robot sled has been improved to offer greater rigidity for the same weight, and dual secondary feedback scales on the vertical axis further improve the rigidity of the overall system. Maintenance access has been improved by rerouting the cable and hose trays, and lowering the electrical cabinet.

Every now and then a good idea happens. The Modular head was a great idea and enabled the use of multiple types of AFP heads, ATL, ply cutting, part probing, etc. with the use of a single machine and machining cell. At the time the modular head was developed by Electroimpact circa 2004, the industry assumed (and accepted) that AFP was an unreliable process. It still isn’t as reliable as we’d like. One way of coping with this lack of reliability is to stage more than one head in the AFP cell so that a spare head of the exact same type is ready to jump into action if the head out on the floor has an issue. If the reliability of the AFP process were to increase 10x or 50x, would there still be a business case for the multiple AFP head system? The modular head may still win the day, but the metrics change. For instance, if there was only 20 minutes of down time for every head load, it may no longer be advantageous to have 2 heads of the exact same type in the cell.

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.

The Electroimpact Automatic Fan Cowl Riveter exhibits new and unique design features and automated process capabilities that address and overcome three primary technical challenges. The first challenge is satisfying the customer-driven requirement to access the entire fastening area of the fan cowl doors. This necessitates a unique machine design which is capable of fitting ‘inside’ a fan cowl door radius. The second challenge is determining drill geometry and drill process parameters which can produce consistent and high-quality countersunk holes in varying mixed-metal stack-up combinations consisting of aluminum, titanium, and stainless steel. The third challenge is providing the capability of fully automatic wet installation of hollow-ended titanium rivets.