CNC Machining of Propeller to Better than Class Tolerances

2015 ◽  
Author(s):  
Slobodan (Bodo) Gospodnetic
Keyword(s):  
High Precision ◽  
Integrated Approach ◽  
Water Jet ◽  
Cnc Machining ◽  
Extreme Surface ◽  
Computer Numerically Controlled ◽  
Surface Blending ◽  
Propeller Blades ◽  
Better Than

Producing class S propellers and water jet impellers presents serious challenges for propeller manufacturers. To overcome these challenges and consistently manufacture propellers with superior quality, an integrated approach was adopted when developing and implementing a process for Computer Numerically Controlled (CNC) machining of propeller surfaces. Highlights of this process are: (1) CNC machining of all blade surfaces; extreme surface blending, (2) CNC machining to final form & finish without hand grinding and (3) high precision, better than class S. This paper will describe various challenges encountered in the production of CP propeller blades and how these challenges were overcome in order to produce accurate CP propeller blades which exceed class S tolerances.

Design for X Approach to Optimise a Formula SAE Car

Volume 2 ◽  
2004 ◽  
Author(s):  
Renzo Capitani ◽  
Tommaso Iacomelli ◽  
Daniele G. Rosti ◽  
Pierluigi Tozzi
Keyword(s):  
Experimental Data ◽  
Integrated Approach ◽  
Design For Manufacturing ◽  
Cnc Machining ◽  
Recursive Method ◽  
Multibody Simulation ◽  
Design For X ◽  
Formula Sae ◽  
Class 1

The Universita` degli Studi di Firenze joined the Formula Student competition (organised by SAE and IMechE) in 2002 competing in Class 3, the following year the first car was ready to compete in Class 1. In order to build this car, an integrated approach was adopted to obtain the best solution in every aspect. The purpose of the design was to optimise the car handling, fulfilling the Formula SAE rules. All the design phases were based on the Design for X approach, with the aim to optimise all the aspects of the Formula SAE project, like performance, design and cost. A Design for Manufacturing approach was added to the FEA to design all the components, like uprights and wheel spindles, in order to simplify the CNC machining. The suspensions layout was defined using a recursive method based on the Multibody Simulation and the components design. Some experimentations were conducted to verify the simulations. The experimental data were used to start the redesign, to improve the performance of the new car that will compete in the 2004 events.

scholarly journals HIPPI-2: A versatile high-precision polarimeter

2020 ◽  
Vol 37 ◽  
Author(s):  
Jeremy Bailey ◽  
Daniel V. Cotton ◽  
Lucyna Kedziora-Chudczer ◽  
Ain De Horta ◽  
Darren Maybour
Keyword(s):  
High Precision ◽  
New South ◽  
New South Wales ◽  
South Wales ◽  
The University ◽  
Better Than

Abstract We describe the High-Precision Polarimetric Instrument-2 (HIPPI-2) a highly versatile stellar polarimeter developed at the University of New South Wales. Two copies of HIPPI-2 have been built and used on the 60-cm telescope at Western Sydney University’s (WSU) Penrith Observatory, the 8.1-m Gemini North Telescope at Mauna Kea and extensively on the 3.9-m Anglo-Australian Telescope (AAT). The precision of polarimetry, measured from repeat observations of bright stars in the SDSS g′band, is better than 3.5 ppm (parts per million) on the 3.9-m AAT and better than 11 ppm on the 60-cm WSU telescope. The precision is better at redder wavelengths and poorer in the blue. On the Gemini North 8-m telescope, the performance is limited by a very large and strongly wavelength-dependent TP that reached 1000’s of ppm at blue wavelengths and is much larger than we have seen on any other telescope.

A New Integrated Design and Fabrication Process for Profiled Edge Laminae (PEL) Tooling

2005 ◽  
Author(s):  
Daniel F. Walczyk ◽  
Seungryeol Yoo
Keyword(s):  
Large Scale ◽  
Integrated Design ◽  
Thick Layer ◽  
Integrated Approach ◽  
Cnc Machining ◽  
Abrasive Waterjet ◽  
Surface Finishing ◽  
Small Scale ◽  
Extensive Surface ◽  
Critical Components

Profiled Edge Laminae (PEL) tooling is a thick-layer Rapid Tooling (RT) method that was developed a decade ago. Even with demonstrable advantages for large-scale tool applications over conventional CNC-machining of a solid billet and other commercially available RT methods, PEL tooling has not seen widespread use by industry because prior research related to laminated tooling has (1) focused on small-scale tools and perpendicular laser-cutting that required extensive surface finishing, and (2) there is no integrated and practical design and fabrication approach to tooling development. This paper describes a more streamlined and integrated approach to PEL tooling development, called the PEL Process, that builds upon prior work in this area. Critical components of the process that are described in detail include how to obtain lamina slicing information directly from a CAD model of the intended tool surface, how to measure dimensional errors between the PEL and CAD tool surfaces, and improved Abrasive Waterjet cutting trajectory and laminae slicing algorithms. The PEL Process is then demonstrated for the design and fabrication of aluminum PEL tooling used for hydroforming aircraft sheet metal components.

scholarly journals Multiplicity of Galactic Cepheids from long-baseline interferometry

2019 ◽  
Vol 622 ◽  
pp. A164 ◽  
Author(s):  
A. Gallenne ◽  
P. Kervella ◽  
S. Borgniet ◽  
A. Mérand ◽  
G. Pietrzyński ◽  
...  
Keyword(s):  
High Precision ◽  
Radial Velocities ◽  
Single Line ◽  
Radial Pulsation ◽  
Mass Measurements ◽  
Long Baseline ◽  
Car T ◽  
Term Objective ◽  
Better Than

Aims. We aim at detecting and characterizing the main-sequence companions of a sample of known and suspected Galactic binary Cepheids. The long-term objective is to accurately and independently measure the Cepheid masses and distances. Methods. We used the multi-telescope interferometric combiners CHARA/MIRC and VLTI/PIONIER to detect and measure the astrometric positions of the high-contrast companions orbiting 16 bright Galactic Cepheids. We made use of the CANDID algorithm to search for the companions and set detection limits from interferometric observations. We also present new high-precision radial velocity measurements which were used to fit radial pulsation and orbital velocities. Results. We report the detection of the companions orbiting the Cepheids U Aql, BP Cir, and S Mus, possible detections for FF Aql, Y Car, BG Cru, X Sgr, V350 Sgr, and V636 Sco, while no component is detected around U Car, YZ Car, T Mon, R Mus, S Nor, W Sgr, and AH Vel. For U Aql and S Mus, we performed a preliminary orbital fit combining their astrometric measurements with newly obtained high-precision single-line radial velocities, providing the full set of orbital elements and pulsation parameters. Assuming the distance from a period-luminosity (P-L) relation for both Cepheids, we estimated preliminary masses of MU Aql = 4.97 ± 0.62 M⊙ and MS Mus = 4.63 ± 0.99 M⊙. For YZ Car, W Sgr, V350 Sgr, and V636 Sco, we revised the spectroscopic orbits using new high-precision radial velocities, while we updated the pulsation parameters for BP Cir, BG Cru, S Nor, and AH Vel. Our interferometric observations also provide measurements of the angular diameters, which can be used in a Baade-Wesselink type analysis. Conclusions. We now have several astrometric detections of Cepheid companions. When radial velocities of the companions are available, such systems will provide accurate and independent masses and distances. Orbital parallaxes with an accuracy better than 5% will be particularly useful for a better calibration of the P-L relation. The final Gaia parallaxes will also be particularly helpful for single-line spectroscopic systems, where mass and distance are degenerate. Mass measurements are necessary for a better understanding of the age and evolution of Cepheids.

scholarly journals A Multi-Counter System for High Precision Carbon-14 Measurements

Radiocarbon ◽  
1980 ◽  
Vol 22 (2) ◽  
pp. 442-447 ◽  
Author(s):  
Hildegard Schoch ◽  
Michael Bruns ◽  
Karl Otto Münnich ◽  
Marianne Münnich
Keyword(s):  
Data Acquisition ◽  
High Precision ◽  
Counting Rate ◽  
Standard Samples ◽  
Carbon 14 ◽  
Laboratory Techniques ◽  
Counting Time ◽  
Precision Level ◽  
Recent Developments ◽  
Better Than

A new 14C detector system containing nine, independently working, CO2 proportional counters is described. The system is designed for a sufficient measuring capacity at a precision level better than σ = ± 2‰, which requires a counting time of about one week per sample. The size of the installation requires a simple and economic design of counters and electronics. A single anticoincidence shield for all counters consists of five newly developed flat counters. The modern counting rate (52cpm) is sensitively checked by running Heidelberg sodium carbonate standard samples wth a counting rate of about 10 times modern. A microcomputer (DEC PDP-11 /03) is used for data acquisition. Recent developments in laboratory techniques (preparation and gaschromatographic purification of samples) are also reported.

Towards a Standards-Based Methodology for Extending Manufacturing Process Models for Sustainability Assessment

2018 ◽  
Author(s):  
Arvind Shankar Raman ◽  
Karl R. Haapala ◽  
K. C. Morris
Keyword(s):  
Manufacturing Process ◽  
Sustainability Assessment ◽  
Building Blocks ◽  
Cnc Machining ◽  
Process Models ◽  
Machining Processes ◽  
Complex Processes ◽  
Information Models ◽  
Computer Numerically Controlled ◽  
Application Specific

Over the past decade, several efforts have characterized manufacturing processes from a sustainability perspective. In addition, frameworks, methodologies, and standards development for characterizing and linking unit manufacturing process (UMP) models to construct manufacturing system models for supporting sustainability assessment have been pursued. In this paper these research efforts are first briefly reviewed, and then, ASTM standards derived from this work are described and built upon. The contribution of this research is to demonstrate how more formalization of these prior efforts will facilitate systematic reuse of developed models by encapsulating different aspects of complex processes into reusable building blocks. The research proposes a methodology to define template UMP information models, which can further be abstracted and customized to represent an application-specific, upgraded manufacturing process. The methodology developed is based on the ASTM standards of characterizing manufacturing process for sustainability characterization. The approach is demonstrated for analyzing manual and computer numerically controlled (CNC) machining processes.

Graticule Ruling in Australia

1949 ◽  
Vol 160 (1) ◽  
pp. 145-153
Author(s):  
Mansergh Shaw
Keyword(s):  
High Precision ◽  
Etching Process ◽  
The Other ◽  
Geographic Isolation ◽  
Precision Machines ◽  
Glass Blank ◽  
Complete Process ◽  
Better Than ◽  
Made In

The problems of precision manufacture in Australia, arising chiefly from her geographic isolation, are first discussed. The paper then takes one particular problem from the field of optical manufacture and shows how it was solved for the conditions prevailing in the Dominion. The problem discussed is the production of graticules, or reticles, for range-finders, predictors, gun sights, telescopes, binoculars, microscopes, collimators, and many other such instruments. The first part of the paper deals briefly with methods used in reproducing the pattern, particularly the ruling and etching process. The second, and much the larger, part of the paper deals with the design of the high precision machines which were made for ruling the glass disks preparatory to etching the pattern into the glass. Two such machines were developed, one generating the pattern from the movements of the machine itself, the other, a pantograph, by copying the pattern from master plates. A series of self-checking tests is described by which the accuracy of the generating machine could rapidly be tested to an accuracy of much better than 0·0001 inch. A brief survey of the complete process, from glass blank to finished graticule, is made in the Appendix.

scholarly journals Generating approximate halo catalogues for blind challenges in precision cosmology

2019 ◽  
Vol 485 (2) ◽  
pp. 2407-2416 ◽  
Author(s):  
Lehman H Garrison ◽  
Daniel J Eisenstein
Keyword(s):  
Dark Matter ◽  
Transfer Function ◽  
Power Spectrum ◽  
High Precision ◽  
Real Space ◽  
Dark Matter Halo ◽  
The Real ◽  
The Galaxy ◽  
Similar Accuracy ◽  
Better Than

ABSTRACT We present a method for generating suites of dark matter halo catalogues with only a few N-body simulations, focusing on making small changes to the underlying cosmology of a simulation with high precision. In the context of blind challenges, this allows us to re-use a simulation by giving it a new cosmology after the original cosmology is revealed. Starting with full N-body realizations of an original cosmology and a target cosmology, we fit a transfer function that displaces haloes in the original so that the galaxy/HOD power spectrum matches that of the target cosmology. This measured transfer function can then be applied to a new realization of the original cosmology to create a new realization of the target cosmology. For a 1 per cent change in σ8, we achieve 0.1 per cent accuracy to $k = 1\, h\, \mathrm{Mpc}^{-1}$ in the real-space power spectrum; this degrades to 0.3 per cent when the transfer function is applied to a new realization. We achieve similar accuracy in the redshift-space monopole and quadrupole. In all cases, the result is better than the sample variance of our $1.1\, h^{-1}\, \mathrm{Gpc}$ simulation boxes.

scholarly journals The Asteroid Mass Determination Project at The U.S. Naval Observatory

1999 ◽  
Vol 172 ◽  
pp. 361-362
Author(s):  
James L. Hilton ◽  
Ronald C. Stone
Keyword(s):  
High Precision ◽  
Mass Determination ◽  
Mean Motion ◽  
Naval Observatory ◽  
Before And After ◽  
Change In The Mean ◽  
The Mean ◽  
The Masses ◽  
The U.S ◽  
Better Than

Asteroid masses are the largest source of unmodeled forces in current planetary ephemerides research. Williams (1984) showed that the asteroids produce km size perturbations in the position of Mars. However, the masses of only three asteroids are known to better than 10%, and only six other asteroid masses have been determined at all.Detecting the mass of an asteroid is difficult because the observed quantity is the change in the mean motion of a second, perturbed asteroid. Asteroid masses are small, so the change in the mean motion is typically on the order of 0."015 yr−1. Thus, excellent orbit determinations are needed both before and after the perturbing encounter. This requires high precision observations over as many oppositions as possible.Hilton (1997) determined the mass of 15 Eunomia to within 25% by detecting perturbations of 1313 Berna. The greatest source of uncertainty in determining the mass of Eunomia was the very poor coverage and accuracy of pre-encounter observations. Hilton (1998) has determined the masses of 1 Ceres, 2 Pallas and 4 Vesta, all based on mutual interactions. The uncertainties in the masses are 1% for Ceres, 3% for Pallas, and 7% for Vesta. The masses of Ceres and Pallas are the best so far, and the mass for Vesta corroborates previous determinations of its mass.

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