Forming tool improves quality of tubing flares

Punch and die set improves the quality of tubing flares for use with standard flared-tube fittings in high-pressure systems. It forges a dimensionally accurate flare in the tubing and forces more tubing material into the high-stress areas to improve the strength and tightness of the tubing connection

Optimisation of the shear forming process by means of multivariate statistical methods

Shear forming is a versatile process for manufacturing complex lightweight components which are required in increasing numbers by many different industries. Inherent advantages of the process are simple tooling, low tool costs, good external and internal surface quality, close dimensional accuracy, and good mechanical properties of the components. In times of free market economy, it is necessary to on the one hand fulfill the increasing demands toward the quality characteristics and on the other hand to reduce the development time needed to manufacture such a high quality component. Since shear forming is a complex and sensitive process in terms of deformation characteristics this is not an easy task. To assess the overall quality of a component several, mutually contradictory, quality characteristics have to be considered simultaneously. While conventionally each characteristic is considered separately, in this paper, a statistical approach is presented which copes with the above mentioned demands and provides the opportunity for an efficient, multivariate optimisation of the process. With a minimum of statistically planned experiments, mathematical models are derived which describe the influence of the machine parameters and their interactions on quantitative as well as qualitative component characteristics. A multivariate optimisation procedure based on the concept of desirabilities is used to find the best compromise between the mutually contradictory quality characteristics. With this statistical approach a workpiece for electrical industry is manufactured which requires a very good surface quality and close geometrical tolerances. --Shear forming,experimental design,multivariate optimisation,high voltage divider

Fabrication and repair of graphite/epoxy laminates

New forming and patching methods have been developed for high-quality graphite/epoxy laminates. Laminates range in thickness from 0.012 to 0.018 in. (0.31 to 0.46 mm)

INEL Spray-forming Research

Spray forming is a near-net-shape fabrication technology in which a spray of finely atomized liquid droplets is deposited onto a suitably shaped substrate or mold to produce a coherent solid. The technology offers unique opportunities for simplifying materials processing without sacrificing, and oftentimes substantially improving, product quality. Spray forming can be performed with a wide range of metals and nonmetals, and offers property improvements resulting from rapid solidification (e.g., refined microstructures, extended solid solubilities and reduced segregation). Economic benefits result from process simplification and the elimination of unit operations. Researchers at the Idaho National Engineering Laboratory (INEL) are developing spray-forming technology for producing near-net-shape solids and coatings of a variety of metals, polymers, and composite materials. Results from several spray forming programs are presented to illustrate the range of capabilities of the technique as well as the accompanying technical and economic benefits. Low-carbon steel strip greater than 0.75 mm thick and polymer membranes for gas/gas and liquid/liquid separations that were spray formed are discussed; recent advances in spray forming molds, dies, and other tooling using low-melting-point metals are described

Spectral classification of emission-line galaxies from the Sloan Digital Sky Survey. I. An improved classification for high redshift galaxies

We study the spectral classification of emission-line galaxies as star-forming galaxies or Active Galactic Nuclei (AGNs). From the Sloan Digital Sky Survey (SDSS) high quality data, we define an improved classification to be used for high redshift galaxies. We classify emission-line galaxies of the SDSS according to the latest standard recipe using [Oiii]5007, [Nii]6584, [Sii]6717+6731, H, and H emission lines. We obtain four classes: star-forming galaxies, Seyfert 2, LINERs, and composites. We then examine where these galaxies fall in the blue diagram used at high redshift (i.e. log([Oiii]5007/H) vs. log([Oii]3726+3729/H).We define new improved boundaries in the blue diagram for star-forming galaxies, Seyfert 2, LINERs, SF/Sy2, and SF-LIN/comp classes. We maximize the success rate to 99.7% for the detection of star-forming galaxies, to 86% for the Seyfert 2 (including the SF/Sy2 region), and to 91% for the LINERs. We also minimize the contamination to 16% in the region of star-forming galaxies. We cannot reliably separate composites from star-forming galaxies and LINERs, but we define a SF/LIN/comp region where most of them fall (64%).Comment: 6 pages, accepted for publication in A&

A Robust Optimisation Strategy for Metal Forming Processes

Robustness, reliability, optimisation and Finite Element simulations are of major importance to improve product\ud quality and reduce costs in the metal forming industry. In this paper, we propose a robust optimisation strategy for metal\ud forming processes. The importance of including robustness during optimisation is demonstrated by applying the robust\ud optimisation strategy to an analytical test function and an industrial hydroforming process, and comparing it to deterministic\ud optimisation methods. Applying the robust optimisation strategy significantly reduces the scrap rate for both the analytical\ud test function and the hydroforming proces

Controlling the Microstructure of Arc Sprayed Shells

Techniques for controlling the microstructure of sprayed steel structures are discussed in this paper. Steel is arc sprayed onto shaped substrates to form tooling. The quality of the tool is greatly influenced by the microstructure of the material and the interlamella regions of the deposit. This work is focused on characterizing the microstructure, improving the state of the inter-lamella regions, and discusses our success in forming pseudo-alloys and graded shells by mixing sprayed materials. Microstructure control has interesting implications for other research as well, such as the MASK & DEPOSITS approach of forming objects.Mechanical Engineerin

Factors affecting the rheological properties of gels made from hoki (Macruronus novaezelandiae) : a thesis presented in partial fulfillment of the requirements for the degree of Master of Technology at Massey University /

Hoki (Macruronus novaezelandiae) is an important commercial fish in the New Zealand Exclusive Economic Zone. The resource remains underutilized with only a small proportion of the 250,000 tonnes Total Allowable Catch presently being made into added value products. There is interest in producing surimi, a refined, stabilized form of fish mince, from hoki. Surimi is an intermediate raw material used for the production of a range of fabricated foods. The rheological properties of these gel-based foods are of key importance for their consumer acceptability. The quality of surimi is determined predominantly by the gel-forming ability of the myofibrillar protein of the raw material fish used in the process. These properties change with chilled and frozen storage of the fish. The objectives of this study are to develop methodology to test the gel-forming ability of surimi; to investigate the changes in gel-forming ability of hoki with chilled and frozen storage, and to evaluate the rheological methods used in these studies. The implications with respect to a domestic surimi industry are discussed. The rheological properties of gels made from hoki stored for various times, chilled or frozen, were determined using two failure tests, namely the puncture test and the torsion test. The puncture test is an empirical method commonly used in the surimi industry, where a 5 mm diameter spherical probe is driven into the gel at constant plunger speed. The force and deformation at failure are used to describe the mechanical properties of the gels. The torsion test is a fundamental method whereby a pure shear state is obtained by applying a twisting moment about a central axis. The shear stress and true strain at failure are calculated and used to follow the changes in gel properties with time. The strength of gels decreased as the fish spoiled on chilled storage. The decline appears to be slower than that reported for other fish such as Alaska pollock. Even after 10 days storage the gel strength was such that hoki would still have excellent gelling properties based on Japanese classification systems. The storage of headed and gutted hoki at -29°C resulted in a significant loss of gel-forming properties over time. The strength of gels were less than the minimum for Japanese ship-processed surimi after about 100 days storage. Hoki appears to lose gel-forming ability with frozen storage at a similar rate to that of Alaska pollock. Measurement of the pH and formaldehyde concentration of the flesh were good indicators of the gel-forming ability of frozen stored hoki. The true strain at failure showed the highest correlation with storage time. Finally, the puncture and torsion tests were evaluated with respect to their use for specifying surimi quality. Specifically their precision, cost, convenience and correlation with a sensory method, were assessed. The results of the storage studies were pooled to provide data covering a wide range of gel textures. Parameters from both tests showed significant correlations with the sensory method, with the puncture force showing the greatest overall correlation. Both methods showed good response to changes in fish quality. There was a large error associated with the puncture force value when firm gels were tested. Standard deviations of up to 25% of the mean were measured. The other parameters for both tests gave standard deviations of about 10%. This demonstrated the high error normally associated with failure testing, and the difference between a point test where the applied force is concentrated over a small area and the torsion test where the stress is applied over a larger area hence averaging the effect small defects may have on failure of the sample. It was concluded that the puncture test is suitable for routine quality testing of surimi, however both the force and deformation results should be reported. For research and when more accurate specification of quality is needed then the torsion test would be more appropriate. Whichever method is used, it is imperative that the preparation and testing of surimi be carried out in a consistent and uniform manner to allow comparison and communication of results. There is a need for a standard industry-wide method for testing the gel-forming ability of surimi. To make consistent surimi an on-shore operation would require strict control of fish quality. Measurement of fish freshness based on organoleptic assessment and the K value may be a useful basis for a hoki surimi quality assessment program. It is probable that the loss of functional gel-forming ability of hoki during frozen storage at -29°C would be too fast to allow the use of frozen hoki for making surimi over an extended period in a commercial operation. Decreasing the storage temperature may extend the useful storage life, but this would have to be balanced against the increased capital and running costs of storage at these lower temperatures

Superplastic forming of Al-Li alloys for lightweight, low-cost structures

Superplastic forming of advanced aluminum alloys is being evaluated as an approach for fabricating low-cost, light-weight, cryogenic propellant tanks. Built-up structure concepts (with inherent reduced scrap rate) are under investigation to offset the additional raw material expenses incurred by using aluminum lithium alloys. This approach to fabrication offers the potential for significant improvements in both structural efficiency and overall manufacturing costs. Superplasticity is the ability of specially processed material to sustain very large forming strains without failure at elevated temperatures under controlled deformation conditions. It was demonstrated that superplastic forming technology can be used to fabricate complex structural components in a single operation and increase structural efficiency by as much as 60 percent compared to conventional configurations in skin-stiffened structures. Details involved in the application of this technology to commercial grade superplastic aluminum lithium material are presented. Included are identification of optimum forming parameters, development of forming procedures, and assessment of final part quality in terms of cavitation volume and thickness variation