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Electroimpact's newest riveting machine features a track-style injector with Bomb Bay Ejection Doors. The Bomb Bay Ejection Doors are a robust way to eject fasteners from track style injector. Track style injectors are commonly used by Electroimpact and others in the industry. Using the Bomb Bay Doors for fastener ejection consists of opening the tracks allowing very solid clearing of an injector when ejecting a fastener translating to a more reliable fastener delivery system. Examples of when fastener ejection is needed are when a fastener is sent backwards, when there are two in the tube, or when a machine operator stops or resets the machine during a fastening cycle. This method allows fasteners to be cleared in nearly every situation when ejecting a fastener is required. Additional feature of Electroimpact's new injection system is integrated anvil tool change.

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.

Very large multi-axis CNC machines offer a special challenge for efficient and accurate machine compensation. Aerospace applications demand tight tolerances, but conventional compensation methods become expensive for large machines. Volumetric compensation offers an approach for reducing costs and improving accuracies. A unique control architecture enabled by volumetric compensation enables the use of a single part program by multiple machines. Combining multiple technologies (a proprietary volumetric compensation solver program, Spatial Analyzer, API's Active Target, a laser tracker and bespoke CNC-Tracker communication software for measurement triggering) significantly reduces machine compensation time. Available analysis tools also enable the engineer to evaluate measurement uncertainties and determine the best locations for additional stations as well as quantify the accuracy benefits such stations would offer.

Growing use of composite materials in aircraft wing construction requires a new generation of drilling machines. Electroimpact's new LTD drilling machine features a Bolt Injector with improvements for more streamlined operation and less operator intervention. The Bolt Injector “injects” or stages Single Sided Temporary Fasteners (SSTF). It features hands-free automated tool change between three different feed paths for a total of eight different fastener diameters being fed through one set of Bolt Injector hardware. This is accomplished with an indexing system for three feed tubes fed to the machine head, with each feed tube serving more than one diameter. Furthermore the LTD Bolt Injector checks fastener diameter at the machine head and also length in conjunction with Bolt Inserter servo axis. The bolt diameter is checked with an analog sensor attached to a gripping mechanism. The length check is accomplished with a “touch off” pad and the Inserter's servo motor encoder.

One of the largest advancements in the use of the Flextrack technology is the addition of automated fastener installation on the Multifunction Flextrack made by Electroimpact. The new Flextrack installs SSTF (Single Sided Temporary Fasteners) into the holes it drills without removing clamp-up force from the workpiece. This is the first Flextrack to drill and install fasteners and its functionality goes beyond even these functions. The fasteners, SSTF bolts, are increasingly replacing more cumbersome and manual tools for temporary fastening of aerospace components during assembly. They provide doweling, clamp-up, and feature a compact head to facilitate machine installation. The new Multifunction Flextrack carries the bolts on the machine head as opposed to being fed through a feed tube. A Bolt Cartridge System carries up to 80 bolts onboard the Flextrack and the Cartridges can be quick changed for use with several different diameters.

Wing and fuselage aircraft structures require large precise tools for assembly. These large jigs require periodic re-certification to validate jig accuracy, yet metrology tasks involved may take the tool out of service for a week or more and typically require highly specialized personnel. Increasing the time between re-certifications adds the risk of making out-of-tolerance assemblies. How can we reduce jig re-certification down time without increasing the risk of using out-of-tolerance tooling? An alternative, successfully tested in a prototype tool, is to bring automated metrology tools to bear. Specifically, laser tracker measurements can be automated through a combination of off-the-shelf & custom software, careful line-of-sight planning, and permanent embedded targets. Retro-reflectors are placed at critical points throughout the jig. Inaccessible (out of reach) tool areas are addressed through the use of low cost, permanent, shielded repeatability targets.

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.

Single Sided Slave Fasteners (SSSF) or Single Sided Temporary Fasteners (SSTF) are increasingly replacing more cumbersome and manual tools for temporary doweling and clamping of aerospace components during assembly. Their ability to clamp provide doweling and clamping reduce the amount of tooling required. Due to their low profile and blind (one-sided) capability, the key benefit of this new technology is the ability to install these fasteners with automated machines. Electroimpact has developed machines to feed primarily SSTF bolts made application-specific by Centrix LLC [ 1 ]. The application discussed in this paper presented problems of confined spaces where a variety of fasteners were required to be fed automatically. To address this, Electroimpact developed new Bolt Injector and Bolt Inserter technology to feed multiple diameters of SSTF bolts in a very small package. Application-specific SSTF were designed such that multiple diameters could be fed through one feed tube.

Accurately measuring the length of a pintail type fastener is limited by the process of forming the fastener. When the pintail is formed its overall length is not dimensionally controlled. To accurately measure the grip of the bolt a vision system is utilized that finds the notch between the tail and bolt shank. The grip, diameter, and angle of the bolt prior to insertion are then measured. This method proves to be more accurate than measuring the bolt mechanically and provides a number of other advantages including; decreased measurement time, improved accuracy, FOD detection, and angle of the bolt in the fingers prior to insertion.

The use of two-piece temporary fasteners is not an option on some build methodologies, processes, or techniques because of limited accessibility. To solve this problem the use of Single Side Slave fasteners (SSSF) were used. With the development of the SSSF, new process tools also needed to be developed to automatically feed and install these fasteners. This paper will cover the development of the process tools used to feed and install SSSF. The tools were designed to automatically insert and torque 1/4\mi - 5/8\mi SSSFs. This paper will cover both the development of the Bolt injector and Bolt inserter.

Electroimpact has designed the E6000, the next generation riveting machine, with a focus on reduced weight and speed. It will initially be used on ARJ21 wing panels in Xi'an, China, but it is able to fasten a variety of panels including A320 and 737. The E6000's fastening cycle is capable of forming and shaving 16 rivets per minute. Head alignment is maintained by two independent four axis heads using a combination of controls and kinematics. Process tool speed has been improved via high lead screws, high speed Fanuc motors, and a shorter head stone drop. An innovative EI operator interface enhances end user experience.

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.

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.

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.

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.

Interference bolts are widely used in aircraft assembly. Electroimpact has used its Low voltage Electromagnetic Riveter (LVER) technology to automatically swage collars on these bolts. The bolts are installed using two process tools, a percussive bolt inserter and the EMR. The bolt inserter inserts the bolt and the EMR swages the collar. This increased productivity over manual installation, but there was still production time to be saved. The Electromagnetic Bolt Inserter (EMB) was designed to increase production rate even more when installing bolts and swaging a collar onto the bolt. The EMB combines the great benefits of Electroimpact's Low Voltage Electromagnetic riveting technology with a bolt inserter.

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.

Spirit AeroSystems' process of producing carbon fiber nacelle panels requires heat and high force plus a high level of dynamic accuracy. Traditionally this would require large and expensive custom machines. A low cost robotic alternative was developed to perform the same operations utilizing an off-the-shelf 6-axis robot mated to a servo-controlled linear axis. Each of the 7 axes is enhanced with secondary position encoders and the entire system is controlled by a Siemens 840Dsl CNC. The CNC handles all process functions, robot motion, and executes software technologies developed for superior dynamic positional accuracy, including enhanced kinematics. The layout of the work cell allowed the robot to span two work zones so that parts can be loaded and unloaded while the robot continues working in the adjacent zone.

There exists a demand in the aerospace industry for highly configurable and flexible automated riveting cells to manufacture small to medium sized panels of complex geometries. To meet this demand Electroimpact has developed a manufacturing system consisting of a stationary Electro-squeeze C-frame riveter, coupled with a robot part positioner to present the component to the process head tool point. The C-frame can install a wide range of aerospace rivets and perform specialist functions including backside countersinking operations, giving potential for double flush fastening. The geometric limitations and high implementation costs of large cartesian based positioning barges or fixed jig tooling and moving gantry riveters are avoided when exchanged for a robot part positioner.

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.