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The E7000 riveting machine installs NAS1097KE5-5.5 rivets into A320 Section 18 fuselage side panels. For the thinnest stacks where the panel skin is under 2mm (2024) and the stringer is under 2mm (7075), the normal process of riveting will cause deformation of the panel or dimpling. The authors found a solution to this problem by forming the rivet with the upper pressure foot extended, and it has been tested and approved for production.

Automation in aerospace industry is often in the form of dedicated solutions and focused on processes like drilling, riveting etc. The common industrial robot has due to limitations in positional a ...

The increased application of lightweight materials, such as aluminium has initiated many investigations into new joining techniques for aluminium alloys. As a result, Self-piercing riveting (SPR) was introduced into the automotive industry as the major production process to join aluminium sheet body structures. Although both hydraulic and servo types of SPR equipment are used by the industry, the servo type is most commonly used in a volume production environment. This type uses stored rotational inertia to set the rivet. The initial rotational velocity of the mass dictates the setting force and hence the tool is described as velocity-controlled. A study was therefore conducted to examine the effect of setting velocity on the process including tooling and joint performance. It was found that the setting velocity would have a significant effect on tooling life. Over 80kN force could be introduced into the tooling depending on selection of the setting velocity. The results also suggested that the joint quality and strength are affected by the setting velocity. An increase in the setting velocity would lead to a decrease in the head height and an increase in the interlock. Too low velocity may cause the rivet head to protrude; too high velocity may result in breakthrough failure. Both cases would lead to corrosion concerns. The examination also indicated that the higher the setting velocity the higher the shear strength of the joints.

Reducing vehicle weight, to improve fuel efficiency and reduce greenhouse gas emissions, continues to be a key objective in the automotive industry. As a result lightweight materials, such as aluminium alloys, are used increasingly for automotive body structures. Currently, self-piercing riveting (SPR) is a major technology used by manufacturers to join aluminium body structures. However, greater demands on the technology present themselves as ever higher strength alloys are required to be joined. The paper reported here focuses on the quality and performance of joints involving AA6008T61, recently introduced for potential applications in automotive body structures. In order to explore the process boundaries, AA6008T61 was supplied with different yield strength values which were obtained through different heat treatment procedures applied by the material supplier. As it is likely that mixed alloy combinations will be required to be joined, body structural aluminium alloy sheet AA5754 with different thicknesses was also be used through this project. The results suggested that SPR is capable of joining AA6008T61 as the top and middle layer with proper rivet/die combination. However, when AA6008T61 was used as the bottom layer, improper selection of die profile could lead to severe cracking. A new type of die with a truncated profile was proved to be able to relieve/improve the cracking situation. The severity of cracking on AA6008 T61 was dependent on the thickness of the top layer and the strength of the AA6008T61 itself. The results show that thinner top material thickness and/or stronger bottom material strength would produce more and larger cracks on the joint button. With the increasing of top material thickness, joint static strengths will increase, and the influence of bottom material strength on joint strength was not significant.

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. The new rivet injector grips the rivet axially and maintains positive control of the rivet from magazine to panel. PC based auxiliary controllers have been eliminated with the customer board.

This paper will cover the design of the horizontal rivet injector use on the SA2 LVER designated for stage 0 production of Airbus A320 Upper Wing Panels. The injector design is intended to decrease cycle times and increase reliability while not reducing the functionality over previous rivet feed designs used by Electroimpact. Specific rivet handling methods and design features will be reviewed and their result on cycle time and reliability discussed.

The Boeing Company (Renton Division) had a requirement for a 30,000 RPM spindle to provide improved surface finish when milling 2034 ice box rivets in hydraulic wing riveters. Electroimpact supplied an electrical spindle which fit into the same cylinder block as the hydraulic spindle. This was reported in SAE Paper #2000-01-3017. Boeing Renton has also now put Electroimpact 20,000 RPM electric drilling spindles into five wing riveting machines so now both spindles in the machine are Electroimpact electric spindles. The electric drill spindle features an HSK 40C holder. Both spindles are powered by the same spindle drive which is alternately connected to the drill and then the shave spindle.

Hydroforming of aluminum sheets is very important in the aircraft industry, due to the advantages of less wrinkling and cost effectiveness. Numerous research has been conducted in this field, which deals with the development of methods and tools to control accuracy of the bend and prediction of the springback after the sheet metal has been formed. Rivets are the most commonly used fasteners to fit together the subassemblies of the aircraft. The holes for riveting are punched after any forming operation due to the tensile and compressive deformations along the thickness of the sheet metal, which can affect the dimension and position accuracy of the hole. This incurs more cost and time due to the development of special dies for accurately punched holes. It is necessary to develop a method for predicting variation in the holes, which will increase the cost effectiveness of the process. In this research, sheet metal with pre-drilled holes was evaluated for a bending operation using a hydroforming technique. Sheet metal with a variety of thicknesses, bending radii, and bending angles was evaluated. Variation in the dimensional tolerance was attained using the minimum radial separation method. A dataset of dimensional variation in the holes was developed and used for development of the artificial neural network, which was able to predict the dimensional variation of the hole if an unknown pattern of inputs was provided. This study presents the prediction of the dimensional variation of holes due to sheet metal bending using the hydroforming technique.

This work compares three aluminium sheet joining processes to determine their capability, efficiency and cost for mass production applications in automotive structures and closures. The joining processes investigated are Resistance Spot Welding (RSW), SelfPierce Riveting (SPR) and Spot Friction Joining (SFJ). Quantitative comparisons have been made on the basis of tensile strength (shear and peel), process time, equipment price and running cost. RSW is the most commonly employed joining method for steel sheet in the automotive industry. Its principle benefits are high speed and low cost operation, plus the ability to weld a wide range of joint configurations with the same gun. The main process limitations for aluminium are weld consistency and electrode-life, though recent work has shown that both of these can be largely overcome with regular electrode polishing

A study examining the effect of coatings on the quality and behaviour of self-piercing riveted joints joining aluminium NG5754 to HSLA350 sheets was conducted. Two types of coatings: E-coated and Zinc plated were applied to the HSLA350 sheet for this study. The results showed that coating affected the joint quality in terms of head height, interlock and remaining material thickness. Examination of joint sections indicated that the self-piercing riveting process needed different setting parameters for coated and uncoated sheets in order to achieve optimum setting conditions. The joint strength was also affected by sheet coatings. However, whether the joints with coated sheet had higher strength was dependent on joint setting conditions. Different coatings had different effects on joint quality and behaviour and different setting conditions led to different behaviour of the joints with or without coatings.

Friction Stir Welding (FSW) of skin stiffened structures is being developed as a rivet replacement technology in the aerospace industry. Preliminary research was done on compressive strength and deformation characteristics of FSW aluminum skin stiffened panels. 7075-T6 aluminum sheets were bent to form stiffeners and friction stir welded to 7075-T6 aluminum sheets to fabricate two FSW panels. Another stiffened panel of similar dimensions was made by using traditional riveting. The compression test results and the failure modes of the panels are presented in this paper. The tests revealed that the FSW panels failed at approximately 17% higher load than the riveted panel. The failure loads of the FSW test panels were within 3 to 10% of the predicted load obtained by using two existing theoretical methods, and the failure load of the rivet panel was within 11 to 20% of the predicted load.

Friction Stir Welding (FSW) is being developed as a rivet and resistance spot welding replacement technology for aerospace and aircraft structures. While the FSW process is at a high Technology Readiness Level (TRL) and is being implemented on selected DOD and NASA hardware components, it has not seen extensive application due to limitations in the understanding of the design constraints and fixturing issues associated with a producible design. This paper describes the preferred FSW joint types and designs for beam structures which facilitate production implementation. The effects of fixturing and tooling on the FSW process development needs and resultant joint properties are discussed along with examples of fixturing and tooling approaches for fabrication of aluminum stiffened beam assemblies.

The General Motors (GM) Corvette design team was challenged with providing a C6 Z06 vehicle spaceframe that maintained the structural performance of its C5 predecessor while reducing mass by at least 56 kg. An additional requirement inherent to the project was that the design must be integrated into the C6 assembly processes with minimal disruption, i.e. seamless integration. In response to this challenge, a collaborative team was formed, consisting of design engineers from General Motors, Alcoa and Dana Corporation. The result of this collaborative effort is an aluminum Z06 spaceframe that satisfies the high performance expectations of the vehicle while reducing the mass by approximately 62 kg. The frame consists of aluminum extrusions, castings and sheets joined by MIG welding, laser welding and self-piercing rivets. The extrusions are 6XXX series alloys, the castings are permanent mold A356 while the sheet panels are formed from the 5XXX series of alloys. Of particular note are the hydroformed aluminum rails, designed to match the steel rails of the base C6 vehicle. Extensive FEA verification, combined with Alcoa's aluminum material processing knowledge, was utilized during the design phase of the program to place mass where it would best serve the structural needs of the vehicle. Performance, mass and cost were balanced to provide an optimized aluminum Z06 spaceframe design that enables the seamless integration of the Z06 into the C6 assembly processes at Corvette Assembly Plant in Bowling Green, Kentucky.