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Technical Paper

An Investigation into the Use of Small, Flexible, Machine Tools to Support the Lean Manufacturing Environment

Drilling fastener holes in large assemblies is traditionally accomplished through the use of large machine tools in order to obtain the accuracies required for the assembled part. Given recent advances of machine design and machine controller compensation, the accuracy of the motion platform can be corrected if the machine is repeatable. This coupled with the use of a vision system or touch probe to compensate for assembly variations, permit the use of smaller, more portable drilling systems. These smaller, more portable machine tools allow for lean manufacturing techniques to be incorporated into build processes, utilize less floor space, and in many cases are less costly than larger, permanent machine tools. This paper examines the feasibility of utilizing a small 5-axis, portable, drilling system for drilling the side panel skins on the F/A-18 E/F forward fuselage.
Technical Paper

Specification Reform of Avionics Thermal Design Criteria – An F-15 Case Study

Traditional thermal design criteria for avionics equipment are reviewed. Several studies have recently been conducted on the F-15 to assess accuracy of these design criteria. An overview of the study approach and results are presented. Specific topics investigated include: emergency cooling air provisions, cold start-up, hot start-up, normal and transient bay temperatures, and altitude design. The results indicate that many existing design criteria are overly conservative. The study findings suggest that reform of the existing thermal specification process is needed. Many of these reforms are applicable to the general aerospace industry and may result in significant acquisition cost savings as a result of the trend toward usage of commercial electronic parts. The reforms suggested include a new performance based thermal specification approach that increases emphasis on aircraft usage and frequency of occurrence. New transient design criteria are also recommended.
Technical Paper

Machine Readable Coding of 777 Wing Fastening Systems Tooling

This paper presents a detailed overview of the advantages and benefits of using 2-D barcodes, called Data Matrix codes, on Wing Fastening System (WFS) Tooling. This project was conducted on, but not limited to, the 777 Wing Fastening System (GEMCOR) tooling including the drills, fingers, and button dies. This paper will show how using Data Matrix codes to identify tooling will: Eliminate excessive downtime due to the operator using the incorrect tooling for a given tool setup. Reduce the cost associated with panel rework due to the use of incorrect tooling. Reduce the cost associated with excessive tool inventory or last minute ordering to keep up with production needs. Track tool life information for each specific tool. Provide operators with an easy to use tool setup reference document. And provide the factory with the ability to trace panel damage or defects back to the specific machine and exact tooling used.
Technical Paper

Gaugeless Tooling

At The Boeing Company, the advent of a Determinant Assembly (DA) program and the subsequent production of accurate fuselage subpanels created a need to be able to position subpanels accurately and repeatably during fuselage assembly. The tool engineering organization of The Boeing Company and Advanced Integration Technology, Inc. (AIT) as the prime contractor, are developing and installing automated positioning and alignment systems throughout major 747 fuselage assembly areas which enable DA techniques. The benefits of this assembly approach and this automated precision tooling are flexibility, assembly accuracy, ease of assembly and associated speed, reduced downtime for tool maintenance, and improved shop-floor ergonomics.
Technical Paper

Airplane Flow-Field Measurements

The utility of airplane flow-field measurements for wind-tunnel testing is reviewed. The methods and equipment developed at Boeing for these measurements are also described. The details of the latest system are presented along with typical results from recent wind-tunnel tests. Using the latest system, flow-field surveys of airplane configurations in industrial low-speed and transonic wind tunnels provide spatial distributions of lift and drag (profile and induced) with good repeatability. In addition, the probe speed and survey region is optimized so that typical full-wake surveys take 20-30 minutes to complete. Final data, displayed as total pressure, velocity vectors, vorticity contours, and distributions of lift and drag (profile and induced) are available approximately 10 minutes after survey completion.
Technical Paper

Process Automation Through-Reality Graphics, Kitting, and Automated Panel Protection

This paper addresses process improvements through reality graphics (RG) aided by automated panel protection (APP) and tool kitting pertaining to automated wing riveting and fastening. This system provides an integrated display of numerical controlled media, automatic tool identification, and image files, combined with automated panel protection. Reality graphics (image files) within the NC program allow the machine operator to access portions of the NC program while attaching a support graphic. This would include safety hazards, unique panel differences, program start, and tool change information. Automated panel protection (APP) analyze process key characteristics, and perishable tool kits, and it monitors the installation of fasteners using multiple cameras mounted in strategic positions, taking real-time images. The APP detects incorrect tooling and possible panel damage, with little or no impact to the operational cycle time of the automated fastening equipment.
Technical Paper

Space Station THC/IMV Development Test/Analysis Correlations and Flight Predictions

The International Space Station (ISS) Temperature and Humidity Control/Intermodule Ventilation (THC/IMV) system for the U.S. Lab provides required cooling air for the U.S. Lab and also provides “parasitic” cooling air for Node 1 and its attached elements. This scheme provides cooled air from the Lab THC directly to Node 1 and also to elements attached to Node 1, at different stages of Space Station assembly. A development test of the U.S. Lab and Node 1/attached elements' integrated THC/IMV ducting system was performed in the summer of 1995. This test included the U.S. Lab's development level Common Cabin Air Assembly (CCAA), which removes sensible and latent heat from the circulated and ducted cabin air. A referenced 1996 ICES Paper contains the initial correlation results. An analytical model has been developed, which has been used to predict flow and pressure drop performance of the system for several potential and actual changes from the Development Test configuration.
Technical Paper

Temperature Control Analysis for the U.S. Lab, Node 1, and Elements Attached to Node 1

The International Space Station (ISS) Temperature and Humidity Control (THC) system has been designed with the intent of supplying the air cooling needs of various elements from the U.S. Lab heat exchanger assembly. Elements without independent air cooling capability are known as “parasitic” elements; these are Node 1, the Cupola, and the Mini Pressurized Logistics Module (MPLM). Analysis results are presented which show expected temperatures in the MPLM, and Node 1, as various heat loads are present in the respective elements. Analyses within this paper are coordinated with the results obtained from the Development Test of the complex USL/Node 1 integrated ducting system. This test was conducted in the summer of 1995, at the McDonnell Douglas test facility in Huntington Beach, California.
Technical Paper

Evolution to Lean Manufacturing A Case Study of Boeing of Spokane

The evolution of a manufacturing organization toward “Lean” manufacturing does not necessarily come cheaply or quickly. It is the experience at Boeing that technology and different visions can dramatically impact the evolutionary process-consuming great amounts of time and resources. The Boeing of Spokane case study, where aircraft floor panels are manufactured1, is but one of several case studies that suggests moving to “Lean” manufacturing is usually done in large steps, not small ones. These initial steps can be costly unless the systems (equipment and workforce) are flexible. Workforce flexibility is dependent on the attitude in the workforce as both touch and support labor move from their comfort zone to try new approaches and job descriptions. The workforce must be properly motivated to make the change. The equipment must also be flexible in adapting to new line layouts, product mixes, and process change or large cost penalties will be incurred.
Technical Paper

Incipient Failure Detection - The Detection of Certain Contaminating Processes

Three separate and distinct electrolytic and one galvanic process were identified by visual inspection, metallographic, electron microprobe, and x-ray diffraction analysis in a clocked, flip-flop integrated circuit flat pack and/or the associated printed circuit test jig (two on flat pack and two on circuit board). These four processes were all found to be detectable by the use of noise measurements in microvolts per root cycle at 1000 Hz (cycles per second). The direct current applied for noise measurement to the integrated circuit devices was 100 micro-amperes, as compared to the 6-8 milliamperes required for normal operation. After initial experimentation, the devices were caused to fail in a laboratory ambient environment, followed by an acceleration of the rate of electrolytic reaction through the use of essentially 100 percent relative humidity, versus the upper specification limit of 80 to 98% relative humidity.
Technical Paper

Problems of Maintaining Equipment Containing Integrated Circuits

This paper discusses some of the problems of developing and maintaining equipment containing integrated circuits. The problems discussed fall into three categories: (1)Processing, (2) Fault Isolation, and (3) Human Error. Quantitative study of these problems shows the highest number were experienced during preliminary-manufacturing and testing (screening and burn-in), with a decrease during final manufacturing checkout (board assembly and final testing) and a minimum during the system operational period. The paper concludes that maintainability is still the necessity it was even with the advent of reliable integrated circuits. This is substantiated by the many failures and defects encountered during manufacturing and development phases. Manufacturing economics force the consideration of maintainability in integrated circuit design.
Technical Paper

Radar Detection of Turbulence in the Upper Troposphere

Encounters of jet aircraft with high altitude turbulence prompted the investigation of various techniques to probe and locate turbulence in areas lacking particles (rain drops, hailstones). A promising technique is to measure the radio refractive eddies and gradients by radar backscatter. Radio refractive index eddies can, in principle, be found where an atmosphere characterized by a nonadiabatic lapse rate of refractive index is stirred up by turbulence. A sequence of VHF backscatter experiments which will hopefully lead up to an airborne CAT detector are presented in this paper.