Ablation threshold and etch rate measurements in high-speed ultra-violet (uv) micro-machining of polymers with uv-copper vapour lasers

1995 ◽  
Author(s):  
Alison C. J. Glover ◽  
Elizabeth K. Llly ◽  
Michael J. Withford ◽  
James A. Piper
Keyword(s):  
High Speed ◽  
Etch Rate ◽  
Ablation Threshold ◽  
Ultra Violet ◽  
Micro Machining

scholarly journals Micro-Machining Characteristics in High-Speed Magnetic Abrasive Finishing for Fine Ceramic Bar

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 464 ◽  
Author(s):  
Joonhyuk Song ◽  
Takeo Shinmura ◽  
Sang Don Mun ◽  
Minyoung Sun
Keyword(s):  
Surface Roughness ◽  
High Speed ◽  
High Surface ◽  
Stable Region ◽  
Micro Machining ◽  
Fine Ceramic ◽  
Magnetic Abrasive Finishing ◽  
Abrasive Finishing ◽  
Machining Characteristics ◽  
Diameter Change

The research aims to describe the micro-machining characteristics in a high-speed magnetic abrasive finishing, which is applicable for achieving the high surface accuracy and dimensional accuracy of fine ceramic bars that are typically characterized by strong hardness and brittle susceptibility. In this paper, the high-speed magnetic abrasive finishing was applied to investigate how the finishing parameters would have effects on such output parameters as surface roughness, variation of diameters, roundness, and removed weight. The results showed that, under variants of diamond abrasives sizing between (1, 3 and 9 µm), 1 µm showed comparatively good values as for surface roughness and roundness within shortest processing time. When the optimal condition was used, the surface roughness Ra and roundness (LSC) were improved to 0.01 µm and 0.14 µm, respectively. The tendency of diameter change could be categorized into two regions—stable and unstable. The finding from the study was that the performance of ultra-precision processing linear controlling was possibly achievable for the stable region of diameter change, while linearly controlling diameters in the workpiece.

Experimental Investigation of Mechanical Micro Machining for AL6061-T6 Material

2012 ◽  
Vol 217-219 ◽  
pp. 1880-1884 ◽  
Author(s):  
Chun Jiang Zhou ◽  
Jian Cheng Liu ◽  
Adrian Avila
Keyword(s):  
Surface Quality ◽  
High Speed ◽  
Cutting Temperature ◽  
Cnc Machining ◽  
Micro Milling ◽  
Geometric Feature ◽  
Depth Of Cut ◽  
Micro Machining ◽  
End Mills ◽  
Machining Properties

This paper is to experimentally investigate the mechanical micro machining properties of AL6061-T6 using tungsten-carbide micro end mills. The cutting simulation based on Finite Element Analysis (FEA) method is also conducted to estimate cutting forces, cutting temperature, and minimum chip thicknesses. The simulation results are used for the determination of experimental machining conditions such as depth of cut, feed rates and cutting speeds. A number of slot micro-milling experiments were performed using 400um diameter micro end mills on a 3 Axis CNC machining center attached with a high precision and high speed spindle unit. The machined surface quality, geometric feature shape, cutting burr generation as well as build-up edges are observed in the cutting experiments. Optimum cutting parameters for a better surface quality and smaller burr sizes are suggested.

Micro-Hole Machined by Electrochemical Discharge Machining (ECDM) with High Speed Rotating Cathode

2011 ◽  
Vol 295-297 ◽  
pp. 1794-1799 ◽  
Author(s):  
Shao Fu Huang ◽  
Di Zhu ◽  
Yong Bin Zeng ◽  
Wei Wang ◽  
Yong Liu
Keyword(s):  
High Speed ◽  
Electrochemical Machining ◽  
304 Stainless Steel ◽  
Machining Accuracy ◽  
Micro Machining ◽  
Rotating Speed ◽  
Electrochemical Discharge Machining ◽  
Electrochemical Discharge ◽  
Micro Holes ◽  
Micro Hole

Electrochemical discharge machining (ECDM), based on electrochemical machining (ECM) and electrodischarge machining (EDM), is an unconventional micro-machining technology. In this paper, with the use of water, the process of micro hole on ANSI 304 stainless steel machined by micro-ECDM with high speed rotating cathode is studied. The effects of machining conditions such as the cathode rotating speed and cathode diameter on the surface quality and accuracy of the shape are investigated. The results indicate that a relatively higher electrode rotating speed can improve the machining accuracy of the micro-holes and reduce the electrodes wear.

scholarly journals Planetary nebulae with UVIT: Far ultra-violet halo around the Bow Tie nebula (NGC 40)

2018 ◽  
Vol 609 ◽  
pp. L1 ◽  
Author(s):  
N. Kameswara Rao ◽  
F. Sutaria ◽  
J. Murthy ◽  
S. Krishna ◽  
R. Mohan ◽  
...  
Keyword(s):  
High Speed ◽  
Broad Band ◽  
Fluorescence Emission ◽  
Ultra Violet ◽  
Central Star ◽  
Thermal Processes ◽  
Motion Direction ◽  
X Ray ◽  
The Core ◽  
Bow Tie

Context. NGC 40 is a planetary nebula with diffuse X-ray emission, suggesting an interaction of the high-speed wind from WC8 central star (CS) with the nebula. It shows strong C IV 1550 Å emission that cannot be explained by thermal processes alone. We present here the first map of this nebula in C IV emission using broad band filters on the Ultra-Violet Imaging Telescope (UVIT). Aim. We aim to map the hot C IV-emitting gas and its correspondence with soft X-ray (0.3–8 keV) emitting regions in order to study the shock interaction between the nebula and the ISM. We also aim to illustrate the potential of UVIT for nebular studies. Methods. We carry out a morphological study of images of the nebula obtained at an angular resolution of about 1.3″ in four UVIT filter bands that include C IV 1550 Å and [C II] 2326 Å lines as well as UV continuum. We also make comparisons with X-ray, optical, and IR images from the literature. Results. The [C II] 2326 Å images show the core of the nebula with two lobes on either side of CS similar to [N II]. The C IV emission in the core shows similar morphology and extent to that of diffuse X-ray emission concentrated in nebular condensations. A surprising UVIT discovery is the presence of a large faint far UV (FUV) halo in an FUV filter with λeff of 1608 Å. The UV halo is not present in any other UV filter. The FUV halo is most likely due to UV fluorescence emission from the Lyman bands of H2 molecules. Unlike the optical and IR halo, the FUV halo trails predominantly towards the south-east side of the nebular core, opposite to the CS’s proper motion direction. Conclusions. Morphological similarity of C IV 1550 Å and X-ray emission in the core suggests that it results mostly from the interaction of strong CS wind with the nebula. The FUV halo in NGC 40 highlights the extensive existence of H2 molecules in the regions even beyond the optical and IR halos. Thus UV studies are important to estimate the amount of H2, which is probably the most dominant molecule and significant for mass-loss studies.

MEMS Based Transducer Designs for Monitoring High Speed Impacts

2012 ◽  
Vol 2012 (DPC) ◽  
pp. 000616-000632
Author(s):  
Philip Reiner ◽  
Arthur Jenkins ◽  
Sharon Sanchez ◽  
Tracy D. Hudson ◽  
Michael Kranz
Keyword(s):  
Short Duration ◽  
High Speed ◽  
Response Times ◽  
Signal Strength ◽  
Stress And Strain ◽  
Vibrational Modes ◽  
Micro Machining ◽  
Performance Parameters ◽  
Mems Sensors ◽  
Sensing Applications

MEMS based technologies provide a unique opportunity to develop micro-machined mechanical transducers for a variety of sensing applications. The micro-machining techniques that have been widely used for MEMS sensors provide a viable path for developing miniature sensors required for monitoring stress and strain for high speed impacts. Moreover, this technology allows sensors to be tailored to respond to specific vibrational modes and mode types. In particular, the electro-mechnical properties must be able to support very short response times without compromising signal strength. In this paper, we present the design and fabrication of micro-miniature PNZT based transducers for short duration mechanical impacts. Comparisons of their performance with conventional PZT transducers are presented. A discussion is also given of key performance parameters and the effects of post-fabrication processing and packaging on transducer performance.

Measurement of Air-Fuel Mixing in a Diesel Spray at Engine Relevant Conditions Using UV-VIS DBI Diagnostic

2021 ◽  
Author(s):  
Conner Godbold ◽  
Farzad Poursadegh ◽  
Oleksandr Bibik ◽  
Caroline Genzale
Keyword(s):  
Visible Light ◽  
High Speed ◽  
Liquid Droplet ◽  
Ultra Violet ◽  
Orifice Diameter ◽  
Diesel Spray ◽  
Vapor Concentration ◽  
Fuel Vapor ◽  
Diesel Combustion ◽  
Concentration Data

Abstract Due to the non-premixed nature of diesel combustion, mixing prior to the reaction zone has proven to be one of the primary factors in emissions formation. Therefore, the advancement of diagnostics used to measure mixing fields in diesel applications is imperative for a greater understanding of how in-cylinder emissions mitigation techniques operate. Towards this goal, we have recently demonstrated the use of a high-speed two-wavelength extinction imaging measurement, UV-VIS DBI, for time-resolved measurements of mixing in a diesel spray. This diagnostic operates by back-lighting the spray with ultra-violet and visible illumination. The visible illumination is selected at a non-absorbing wavelength, such that the visible light is only attenuated by liquid droplet scattering, enabling discrete detection of the liquid-vapor mixture and pure vapor phases of the spray. For this work, Ultraviolet and visible light are generated using a ND:YAG pumped frequency-doubled tunable dye laser operating at 9.9 kHz . The simultaneous UV-Visible illumination is used to back-illuminate a vaporizing diesel spray, and the resulting extinction of each signal is recorded by a pair of high-speed cameras. Using an aromatic tracer (naphthalene, BP = 218 °C) in a base fuel of dodecane (BP = 215–217 °C), the UV illumination (280 nm) is absorbed along the illumination path through the spray, yielding a projected image of line-of-sight optical depth that is proportional to the projected fuel vapor concentration in the pure vapor region of the spray. In this paper, a new method of determining the absorption coefficient for the pure-vapor phase of the spray will be discussed, along with showing how an Inverse-Abel transform can be used to compute planar concentration data from the projected concentration data yielded by the diagnostic. This diagnostic and data processing is applied to diesel sprays from two Bosch CRI3-20 ks1.5 single-orifice injectors (140 μm and 90 μm orifice diameters) injecting into a nonreacting high-pressure and temperature nitrogen environment using a constant-flow, optically-accessible spray chamber operating at 60 bar and 900 K. The mixing data produced agrees well with previously existing mixing data, which further instills confidence in the diagnostic, and gives the diesel combustion community access to mixing field data for a 140 μm orifice diameter injector at a 60 bar and 900 K condition.

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