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Spin forming development

Description: Bendix product applications require the capability of fabricating heavy gage, high strength materials. Five commercial sources have been identified that have the capability of spin forming metal thicknesses greater than 9.5 mm and four equiment manufacturers produce machines with this capability. Twelve assemblies selected as candidates for spin forming applications require spin forming of titanium, 250 maraging steel, 17-4 pH stainless steel, Nitronic 40 steel, 304 L stainless steel, and 6061 aluminum. Twelve parts have been cold spin formed from a 250 maraging steel 8.1 mm wall thickness machine preform, and six have been hot spin formed directly from 31.8-mm-thick flat plate. Thirty-three Ti-6Al-4V titanium alloy parts and 26 17-4 pH stainless steel parts have been hot spin formed directly from 31.8-mm-thick plate. Hot spin forming directly from plate has demonstrated the feasibility and favorable economics of this fabrication technique for Bendix applications.
Date: May 1, 1982
Creator: Gates, W.G.
Partner: UNT Libraries Government Documents Department

Stress relief of ceramic components in high voltage assemblies. Final report

Description: Two types of ceramic packages were evaluated to determine the effectiveness of encapsulating the ceramic components in beta eucryptite filled epoxy. The requirements (no high voltage breakdown, no ceramic cracking, and no encapsulant cracking) were met by the spark gap assembly, but the sprytron assembly had cracking in the encapsulant after thermal cycling. The encapsulation of the ceramic component in beta eucryptite filled epoxy with a stress decoupling material selectively applied in the stress concentrated areas were used to prevent cracking in the sprytron encapsulant. This method is proposed as the standard encapsulation process for high voltage ceramic components.
Date: February 1, 1979
Creator: Heinen, R.J.
Partner: UNT Libraries Government Documents Department

Thermal fatigue evaluation of solder alloys. Final report

Description: An evaluation was made of the relative thermal fatigue resistance of 29 solder alloys. A number of these alloys were found to be less susceptible to thermal fatigue cracking in encapsulated printed wiring board applications than the commonly used tin-lead eutectic (63Sn-37Pb). Three alloys, 95Sn-5Ag, 96.5Sn-3.5Ag, and 95Sn-5Sb offered the greatest resistance to thermal fatigue. The selection of the encapsulation materials was confirmed to be a significant factor in thermal fatigue of solder joints, regardless of the solder alloy used.
Date: February 1, 1980
Creator: Jarboe, D.M.
Partner: UNT Libraries Government Documents Department

Thin film gold etchant formulation and rinse removal. Final report

Description: The chemistry of gold etchant solutions used in photolithography of thin film networks (TFNs) for hybrid microcircuits was reviewed. The formulation and operating limits were revised to ensure that the initial solution makeup is always within required values for iodine concentration and specific gravity and that the etchant will not be used for an extended period of time. Rinsing procedures for removal of the gold etchant from the TFNs were evaluated. Increasing the rinse time beyond 15 seconds in deionized water does not significantly improve the removal of iodine. Nitrogen bubble burst, increased temperature of the rinse water, methyl alcohol rinse, and potassium iodide solution prerinse were shown to be effective in improving the rinse removal of iodine. Production requirements for stripping time for wet photoresist were shown to be more than three times longer than necessary to ensure that the photoresist was completely removed.
Date: July 1, 1980
Creator: Raut, M.K.
Partner: UNT Libraries Government Documents Department

Training manual for precision hand deburring, Part 1

Description: Part 1 is presented of 4 parts of a training manual to be used by machinist trainees, production workers, and others removing burrs from precision miniature parts. The manuals are written to be self-teaching and are intended to be used with two hours of training each day and are intended to be used with two hours of training each day along with another six hours of bench work in deburring.
Date: May 1, 1980
Creator: Gillespie, L.K.
Partner: UNT Libraries Government Documents Department

Uniform aluminum deposits on large nonplanar and planar polyimide substrates by physical vapor deposition

Description: The capability to deposit 10- to 12-..mu..m-thick aluminum films with less than 2 percent thickness uniformity (defined as standard deviation/average thickness) on large nonplanar and planar polyimide substrates has been developed using physical vapor deposition (PVD). A technique called shadow masking was developed to provide this consistent deposit uniformity over the entire substrate surfaces (greater than 2000 cm/sup 2/). The specific dimensions of a shadow mask for each substrate are generated from a computer-reduced plot of beta-backscatter thickness measurements of a previous deposit. With this developed method, initial thickness uniformities of 9.7 and 24.7 percent obtained for the nonplanar and planar deposits were improved to 1.07 and 1.80 percent, respectively.
Date: July 1, 1980
Creator: Hale, G.J.
Partner: UNT Libraries Government Documents Department

Shelf life determination of an epoxy resin by accelerated aging

Description: The objectives of the study reported were to first define the rate and mode of degradation of an epoxy resin at two storage conditions, 4.4/sup 0/C and 25/sup 0/C, by means of a thermally accelerated aging experiment. Then, samples which had been aged the equivalent of at least 10 years at each storage condition would be tested for conformance to the material specifications. The study's results demonstrate that the commercial resin could be acquired and stored for the required 10 to 11 years without concern over degradation. The expected changes at the two storage temperatures have been defined. Aged resin samples are shown to yield an acceptable product. Sufficient data exist to predict the changes in viscosity and epoxide equivalent of the resin at any other storage temperature of interest. (LEW)
Date: November 1, 1983
Creator: Smith, H.M.
Partner: UNT Libraries Government Documents Department

Stress relaxation of cellular silicone material

Description: Stress relaxation information for cellular silicone materials formed with urea leachable filler is being gathered. Two types of polymers are used in the test: equilibrium type (random copolymer) and condensation type (block copolymer). Each of these was compounded to provide finished materials with nominal apparent densities of 0.34 and 0.52 g/cm/sup 3/. Three sample variations of 1.17, 1.52, and 2.54 mm nominal thickness were prepared from the lower density product, and two sample variations higher density product. Each of the material/thickness combinations was compressed to nominal compressions of 20 and 40% with nine replicates at each condition. A compression fixture for aging is used to maintain a specific compression on the cellular sample at room temperature, and a test machine is used to acquire the load data. The load was recorded at initial assembly and at selected times thereafter. A total of 180 specimens are in test, 90 equilibrium type material samples that have been stored 4 years and 90 condensation type material samples that have been stored for 3 years. Each condition for each material type has nine replicates. Of these nine samples, two are 3 year controls, two more are 10 year controls, and five are tested regularly. Current data supports the statement that the time dependent loss of load bearing properties is approximately log-linear, with the major differences found to be between the material types and the two densities of each material type. Extrapolation indicates that at the end of the planned 10-year study, the load retention of all samples will be between 58 and 68% of original; the condensation type material is expected to be superior.
Date: May 1, 1980
Creator: Schneider, J.W.
Partner: UNT Libraries Government Documents Department

Syntactic foam supports. Final report

Description: Foams consisting of blends of a polyimide resin and glass microbubbles were prepared to provide thermal protection and energy absorption. With the selected type of glass microbubble, tests wre conducted to measure the effect of foam formulation, microbubble strength, and molding pressure on certain mechanical, thermal, and environmental properties.
Date: June 1, 1980
Creator: McIlroy, H.M.
Partner: UNT Libraries Government Documents Department

Thermistor mount efficiency calibration

Description: Thermistor mount efficiency calibration is accomplished by use of the power equation concept and by complex signal-ratio measurements. A comparison of thermistor mounts at microwave frequencies is made by mixing the reference and the reflected signals to produce a frequency at which the amplitude and phase difference may be readily measured.
Date: May 1, 1980
Creator: Cable, J.W.
Partner: UNT Libraries Government Documents Department

Metrology data reduction system: PDP-11/34 computer system. [MOUNT, for thermistor mount data acquisition, in FORTRAN IV]

Description: A PDP-11/34 computer system was installed to acquire, correct, scale, display, store, and process data obtained by microwave and dc area coupler controllers. The system is used to calibrate power sensors and impedance and dc measurement standards on a real-time basis. The microwave data input is from a digital voltmeter and scanner arrangement, which also may be controlled from a P-ROM control board. The dc data input is from a passive device interface or from a terminal keyboard. 5 figures, 8 tables.
Date: April 1, 1980
Creator: Cable, J.W.
Partner: UNT Libraries Government Documents Department

Moisture penetration evaluation of polystyrene bead foam as an encapsulant for electronic packages

Description: Discs of polystyrene bead foam were used to measure resistance to high-pressure moisture penetration. Densities of 0.2, 0.3, 0.4, 0.5, and 0.6 g/cm/sup 3/ processed at various fusion times and temperatures were tested. Only three fusion conditions for 0.6 g/cm/sup 3/ density were impervious to moisture penetration at 1724 kPa for 24 hours or more.
Date: June 1, 1980
Creator: Swanson, G.D.
Partner: UNT Libraries Government Documents Department

Multilayer printed wiring board lamination

Description: The relationship of delamination resistance of multilayer PWBs made from GF material to manufacturing process variables was investigated. A unique quantitative test method developed during this project shows that delamination resistance is highly sensitive to material conditioning, to innerlayer surface treatment, and to post-lamination storage conditions, but is relatively insensitive to cure cycle variations.
Date: June 1, 1980
Creator: Lula, J.W.
Partner: UNT Libraries Government Documents Department

Plasma etchback of multilayer printed wiring boards

Description: Removal of epoxy smear and glass fiber protrusions in multilayer printed wiring board holes was investigated. Gas plasma techniques, using a mixture of carbon tetrafluoride and oxygen, removed the eposies; however, the glass fibers were not affected.
Date: June 1, 1980
Creator: Gentry, F.L.
Partner: UNT Libraries Government Documents Department

precision deburring using NC and robot equipment. Final report

Description: Deburring precision miniature components is often time consuming and inconsistent. Although robots are available for deburring parts, they are not precise enough for precision miniature parts. Numerical control (NC) machining can provide edge break consistencies to meet requirements such as 76.2-..mu..m maximum edge break (chamfer). Although NC machining has a number of technical limitations which prohibits its use on many geometries, it can be an effective approach to features that are particularly difficult to deburr.
Date: May 1, 1980
Creator: Gillespie, L.K.
Partner: UNT Libraries Government Documents Department

Producing miniature threads. Final report

Description: Miniature precision actuators, timers, and switches typically utilize miniature threads to provide convenient assembly, disassembly and adjustment. Thread rolling provides high-quality external threads with greater strength and lower cost than other thread-producing techniques. Tap breakage is a significant problem when 0.5 and 0.6 Unified National Miniature (UNM) threads must be produced in hard materials such as SAE K95100 high-permeability magnetic steel. Aluminum parts can be tapped with no difficulty in these sizes. Stainless steel 0.5 UNM screws break at loads of 21 lb (53 N). Thread failure occurs at thread heights of 62% full thread or lower.
Date: November 1, 1981
Creator: Gillespie, L.K. & Robb, J.M.
Partner: UNT Libraries Government Documents Department

Pulse plating of hard gold electrodeposits

Description: The conventional and pulse plated, cobalt hardened gold deposits were evaluated and differences in cobalt chemical composition, morphology, and microstructure were determined. Cobalt hardened gold samples were plated on polished brass substrates for morphology study. For microstructure and chemical composition the substrate was stainless steel-304.
Date: February 1, 1979
Creator: Stimetz, C.J. & Hren, J.J.
Partner: UNT Libraries Government Documents Department

Resistance spot welding of Ti-6A1-4V alloy

Description: The effects of weld power, electrode force, electrode tip radius, and elapsed time between cleaning and welding on resistance spot welds in Ti-6Al-4V alloy were evaluated. The alloy is weldable by this technique, and a wide latitude can be taken in processing variables.
Date: June 1, 1980
Creator: Jarboe, D.M.
Partner: UNT Libraries Government Documents Department

Simultaneous measurement of multilayered composites. Milestone report

Description: A theoretical treatment of the eddy current problem involving a two-layered conductor laminate is presented for a rectangular cross section coil, with experimental eddy current measurements indicating that a frequency of 1.5 MHz should be used to measure a 6.45 ..mu..m aluminum conductor, a 0.5 MHz frequency should be used to measure a 50.8 ..mu..m aluminum conductor, and a frequency of 30 MHz should be used to measure lift-off. The schematic and the basic design of a two-frequency microprocessor controlled eddy current system is also presented.
Date: June 1, 1980
Creator: Heckman, R.V.
Partner: UNT Libraries Government Documents Department

Stress relaxation of cellular silicone material: 1980

Description: Bendix Kansas City currently is evaluating the long-term (10 years) stress relaxation properties of cellular silicone materials at room temperature. The cellular structure is formed by using urea as a leachable filler. Both equilibrium (random copolymer) and condensation (block copolymer) type base polymers are included. Each material was compounded to yield two different densities for several thickness combinations. These density-thickness combinations then were compressed to nominal compressions of 20 and 40 percent with nine replicates at each condition. Five are tested regularly, two are 3 year controls, and two are 10 year controls.
Date: September 1, 1980
Creator: Schneider, J.W.
Partner: UNT Libraries Government Documents Department

Power ratings of rf thin film resistive attenuators

Description: Most radio frequency (rf) assemblies built using hybrid microcircuit technology employ thin film attenuators. These attenuators are subject to moderate rf peak power and to moderate average power. Because of intracircuit mismatch, extra considerations of power requirements must be given. To meet these requirements, selected thin film resistive attenuators operated under large rf power conditions were investigated, and the power margin in which these attenuators can be used was defined.
Date: June 1, 1980
Creator: Smith, F.R.
Partner: UNT Libraries Government Documents Department