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Technical Paper

An Aerospace Manufacturing Improvement Process

1991-11-01
912644
Abstract: The two basic methods of process improvement are discussed. The continuous and methodical Japanese system for improvement called KAIZEN is presented along with the typical U.S. approach to improvement called Innovation. The two contrasting methodologies are discussed individually and then are combined to form a strategy for improving the aerospace manufacturing process. The Kaizen of continuous improvements in part fixturing and the innovations of new automatic riveting techniques are combined to provide a tool for survival in the ever increasing competitive aerospace fastening business. The process of transition from today to the future not only means changes in equipment and methods but also changes in people and management. An integrated approach to managing the elements of change is presented. The paper tries the “what is necessary” and the “how to implement” strategies into one comprehensive concept called PROGRESS.
Technical Paper

Project-5 Axis CNC Auto-Riveting

1991-11-01
912647
In the last decade the field of auto riveting has appeared to have lagged behind in its application of computer technology. To move this process into the world referred to as CNC, many traditional concepts need challenged. The manufacturing engineering environment must take the position that riveting can be a machine tool process capable of utilizing the latest in CNC technology. The ability to assemble components with a wide range of tolerances via the accuracy of computers is a reality if proper concepts are employed.
Technical Paper

K-Fast Auto Nut Feeder

1991-11-01
912645
Changes in fastener dimensions & envelop design combined with distance to send fasteners new update torque requirements added to hard copy torque computation & joint historical review has given us, Microdot Aerospace, the opportunity to design, build & sell a new & varied brand of automatic riveter nut running units. We started by changing some of our units from magazine to vibratingbowl feeding & in the process sending fastener up to 150 feet. After this original change we were asked to set up tools with electronic torque control & the ability to store & print each separate nut & hole torque. This machine also acts as its own quality control & gives an instant readng of an out of spec fastener combination. This machine has also been set up to shut off unit if nut is not in place.
Technical Paper

Production Automation Support Advantage's of a Specilized Team

1991-11-01
912637
A new department has been formed called Production Automation Support (PAS). The team will support operations enterprise wide. Their first priority is to concentrate initial efforts on concerns and issues of the automatic fastening machines and their support equipment. The charter for the organization will be directed towards an immediate effect on Douglas Aircraft Company products, through automated fastening systems and their support equipment. The group will be responsible for effecting repairs, design improvements and responsible recommendations that will increase the quality and productivity of these machines.
Technical Paper

Development of a Semi-Automated Fastening Subsystem

1991-11-01
912641
As part of an ongoing effort to automate air-frame assembly at the McDonnell Aircraft Company, an Automated Drilling System has been implemented to perform outer mold-line fastener hole preparation for the AV-8B, Harrier, wing assembly. The skin must be secured to the substructure as the hole preparation progresses in order to assure consistent hole quality and skin to structure fit-up. The development of this capability posed a challenging production engineering problem for McDonnell Aircraft manufacturing engineers to solve. Ultimately, a semi-automatic fastening subsystem was developed to temporarily secure the skin to the structure. This paper outlines the engineering studies and decisions that led to the development of this technology and those that determined its final form.
Technical Paper

Mechanical Joining Characteristics of Aluminum-Lithium in a Production Environment

1991-11-01
912640
Aluminum-lithium (Al-Li) alloys have been developed with reduced weight and increased durability characteristics. The application of these new alloys as primary aircraft structure has created the need for refinements in the mechanical joining and stress-coining processes currently employed throughout the aerospace industry. These processes deal specifically with fastener hole preparation, installation processes, and fatigue enhancement techniques associated with stress-coin cold-working methods for mechanical joints. This paper attempts to dispel the myths associated with such processing of 2090 Al-Li alloy sheet and extrusions. Presented are some lessons learned during assembly of the USAF's new C-17A STOL transport airlifter when utilizing Al-Li material.
Technical Paper

Update of Composite Fastener Technology at BHTI

1991-11-01
912648
Composite fasteners are of great interest to the aircraft industry as an improved method for joining composite structure. Current metal-fastener technology does not adequately address all the relevant concerns, problems that contribute to increased costs, weight, and radar signature. Emerging composite fastener technology offers the potential of alleviating some of these problems. Preliminary data on polyetheretherketone (PEEK) continuous carbon fiber fasteners were developed, coupons were tested, data were analyzed, and preliminary design criteria were established to facilitate application to design. These criteria were then utilized to select potential structural elements and components for fastener installation. A test element was identified, fasteners were installed, a static test performed, and fasteners evaluated in aircraft structure. A component was identified, the fasteners were installed in a secondary composite structure, and flight tests were conducted.
Technical Paper

Process Development for Use of AERAC

1991-11-01
912650
Abstract Two Automated Electromagnetic Riveting Assembly Cells (AERAC) were manufactured for Textron Aerostructures by Electroimpact, Inc. The AERAC installs the final rivets in the A330/A340 upper wing panel in the floor assembly jig. At Textron for each wing the corresponding floor assembly jigs for each wing are lined up end to end. An operating procedure in which the formboards are removed in bays allows efficient operation of an in the jig riveter such as the AERAC. Specialized machine codes developed for the AERAC allows quick fully programmed stringer to stringer jumps of the stringer side offset tooling. The AERAC is programmed entirely from a CATIA drawing of the part. Of the 5 axes of rivet data available only two are retained for use by the AERAC.
Technical Paper

The High Strength Cold Forging Applications of a New Low Carbon Multi-Phase Steel

1992-02-01
920531
A new microalloyed, multi-phase low carbon steel has been developed as an alternative to the QT steels which have traditionally been used in the fabrication of high strength cold forged products. The benefits of this new steel include: (1) the elimination of spheroidize annealing prior to cold forming; (2) the elimination of the QT heat treatment after the deformation; and (3) the ability to achieve in the final component yield strengths of desired levels, high fatigue resistance and very high notch toughness. The excellent properties exhibited by this steel are a direct result of the advanced thermomechanical or controlled processing of the austenite during bar and/or rod rolling. This paper will first briefly review the physical metallurgy of this steel as it pertains to cold forming. This will be followed by a review of industrial trials where various components have been cold forged from this steel.
Technical Paper

Advanced Concepts for Modular Glazings

1992-02-01
920201
To continue the evolution of concepts for modular glazing, a rational new technique has been developed, providing ready-to-install glass modules, which feature an extruded vendor-applied functional urethane basic profile on the inside glass edge, which incorporates a custom shaped dam, and a spacer lip, which serves as retainer and weatherstrip. The only assembly operation is the addition of the adhesive bead, and installation in the car body. The featured benefits are: perfect, attractive, flush glazed design instant integration into today's robotic and automated assembly systems maximum assembly efficiency at minimum cost increased reliability improved quality of adhesive process reproducable design and process parameters
Technical Paper

Design Guidelines for Torque Controlled Tightening of Bolted Joints

1993-03-01
930578
This paper proposes a set of design guidelines to assist the Engineer when torque tightening of threaded fasteners is to be used for product assembly. Discussed are the factors which affect the bolt preload (tension) such as frictional scatter, the accuracy of the torque tightening method, and the effect of fasteners having a prevailing torque characteristic. The consequence which the use of special bolts, such as those having flange heads or reduced bolt shanks, have on the tightening torque and preload is also considered. It is shown that as the variation in the coefficient of friction increases, the correct tightening torque to specify to avoid bolt failure, and the maximum preload which can be ensured based upon this torque, both reduce in magnitude. An improvement in the reliability of products using bolted joints assembled by the torque tightening method can be assisted by use of the proposed guidelines.
Technical Paper

CNC Fastening of Large Aircraft Structures

1993-11-01
931772
Abstract: The use of CNC automatic fastening on large aircraft structures requires a process-oriented approach. Included in that process are factors related to the parts and assemblies, tooling, machine control data, as well as the automated fastening machine itself. This paper summarizes some challenges and solutions that occurred during the production implementation of such a CNC assembly process for very large aircraft structures.
Technical Paper

Measurement of Fastener Head Protrusion in Automated Systems with a Capacitive Sensor

1993-09-01
931771
A capacitance sensor has been developed for measuring the protrusion of fastener heads. The capacitance sensor is easily integrated into an automated rivet installation system. The sensor is capable of measuring the protrusion of a fastener head relative to the skin surface, even in the presence of corrosion protective films used on the aircraft skin surface during manufacture. This paper presents a brief review of the capacitance measurement method. The mechanical design and operation of the sensor are presented as well as information regarding the integration of the sensor within an automated riveting system. Another novel capacitance-based inspection system has been developed for characterization of critical fastener dimensions. Design, capabilities, and inspection data obtained with the fastener measurement system are presented.
Technical Paper

Torque Reactionless Differential Hand Held Rotary Power Tools

1993-09-01
931774
The heavy financial burden that workers compensation and health insurance place on the aircraft industry is of crisis proportion. One of the leading contributors to this crisis is Cumulative Trauma Disorders (CTD's) that result from the use of hand held rotary power tools. The use of ergonomically designed power tools will greatly reduce the risk of developing CTD's and offers the aircraft industry a long term solution to reducing this cost. This paper presents a hand held fastener installation tooling system based upon a revolutionary concept eliminating 100% of the reaction torque, that until now, the users of conventional tools have had to endure.
Technical Paper

A Complete Approach to Automated Assembly

1993-09-01
931768
Technological advances have made it possible to advance assembly of aircraft from the days of “Rosie the Riveter” to automated manufacturing facilities of the future. Improvements in CNC controlled machines, called Positioners, and tooling, called End Effectors, have enabled the assembly process to pass from, two people, to robots working on opposite sides of a panel. Further developments with Multi-functioning End Effectors and stiffer more accurate Positioners have reduced the station to station cycle times of completely assembled panels. New generation systems show even greater promise for, not only lower cycle times, but lower investment costs and higher reliability.
Technical Paper

Open Communication to Satisfy Cost Effective Automation Objectives

1993-09-01
931766
Each automation project begins with the desire to perform an established task, or never before performed task in the most technically feasible and cost effective manner. The desire to automate is typically accompanied by anticipated improvements in quality, throughput, and reductions in production cost. The ideal situation would involve supplier evaluation of a project in its infancy, and recommendation of an approach before any bias by the project implementation team can take hold. Unfortunately, today's practices usually invite suppliers of automation technology to participate and provide input long after key (early) decisions are made, which significantly hamper the supplier's offering and in turn limit the technical feasibility and cost effectiveness of the approach.
Technical Paper

The “Aerolock” Rivet's Contribution to Automated Fastening

1993-09-01
931775
The development of improved fastening systems has made a substantial contribution to the consistency and repeatability of the rivet installation process in the Aerospace Industry. In order to take maximum advantage of the fatigue life improvement that this repeatability makes possible, the industry has expended substantial effort in identifying those parameters that govern the hole fill that can be achieved. A rivet has been designed which expands in a more predictable and controllable fashion than rivets currently in use, and which therefore is more “forgiving to the hole”. This new rivet's superior ability to adapt, in combination with automated systems capability to limit the deviation in hole size, has provided the industry with the means of achieving substantially higher fatigue life. The rivet, originally developed by Lockheed, is called the Aerolock and its introduction has made a substantial contribution to the enhancement of manually and automatically installed rivets.
Technical Paper

FACAI - A Flexible Assembly Cell for Aeronautical Industry

1993-09-01
931770
The Flexible Assembly Cell for Aeronautical Industry (FACAI) is described. The cell was developed in order to take advantage of the benefit of hard automation while retaining the flexibility of the manual assembly system it replaces. A description of both the generic equipment, selected to be non-specific to both the process and the assemblies intended to be built, is provided. In addition, all specific hardware, including end-effectors and fastener distribution systems are described, along with the rationale for their choice. The reasons for the modular design are explained. The means by which the flexibility goal was achieved are outlined. The demonstrated ability of the cell to install a wide range of fasteners (solid rivets, lockbolts, Hilocks) without the need for manual reconfiguration is detailed. The means by which both the quality and safety goals were attained are explained.
Technical Paper

Today's Changing Process Development Environment

1993-09-01
931762
The concept of Concurrent Engineering as it applies to the design and development of new fixtures, tools and automated machinery is discussed. The communication paths that are necessary to allow ideas and data to flow freely and creatively throughout the process development cycle are defined. The technical, financial and legal aspects of a concurrent engineering process development cycle involving a final customer and several vendors is presented. The paper provides a model for other Aerospace Companies to follow in planning their current and future automation requirements.
Technical Paper

Giddings & Lewis Mechanized Fastening System

1993-09-01
931764
The general goal of this paper is to show how an integrated approach to simultaneous engineering can reduce lead times from conception to reality, improve quality, reduce variations, and cut costs. The correct framework for simultaneous engineering establishes quality goals, determines manufacturing needs, develops product features, and defines process characteristics.
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