Comparing the Effects of Ultrasonic System of the EDM Process on Machining Cemented Carbide

2019 ◽  
Vol 950 ◽  
pp. 195-199
Author(s):  
Boonsong Chongkolnee ◽  
Chaiya Praneetpongrung
Keyword(s):  
Ultrasonic Vibration ◽  
High Frequency ◽  
Small Amplitude ◽  
Vibration Amplitude ◽  
Low Frequency ◽  
Cemented Carbide ◽  
Tool Electrode ◽  
Vibration Technique ◽  
Machining Properties ◽  
Large Vibration Amplitude

This research aim to improve the machining properties of the EDM for cemented carbide. The new methods were designed and proposed to use the ultrasonic vibration technique. Two types of USEDM systems were produced. One had a low frequency of 29 kHz with a large vibration amplitude, while the other had a high frequency of 59 kHz with a small amplitude. The Cu-W tool electrode was synchronized with the devised vibration system, and several discharge generation conditions were carried out on the cemented carbide material. The results showed that the highest machining efficiencies were obtained from the ultrasonic low frequency of 29 kHz with a large vibration amplitude. The MRR, TWR and surface roughness of the ultrasonic low frequency with the large vibration amplitude were better than the high frequency system with the small amplitude system. It was clarified that the ultrasonic vibration with the large amplitude could assist the material removal behavior of the discharge.

Design and Research on the New Combining Vibrating Screen

2011 ◽  
Vol 201-203 ◽  
pp. 504-509 ◽  
Author(s):  
Nian Qin Guo ◽  
Hong Min Lou ◽  
Wei Ping Huang
Keyword(s):  
High Frequency ◽  
Large Amplitude ◽  
Small Amplitude ◽  
Low Frequency ◽  
The Other ◽  
Vibration Exciter ◽  
Vibrating Screen ◽  
Screening Efficiency ◽  
New Type ◽  
Equal Thickness

Basing on the traditional vibrating screen with double amplitudes and different frequency, a new type vibrating screen called combining vibrating screen is developed. It consists of two vibrating screen units. Each unit has an independent vibration exciter, realizing that one screen unit has a parameter of high-frequency with small-amplitude while the other screen unit has a parameter of low-frequency with large-amplitude. The two screen units are installed at different obliquities, so that the equal thickness screening principle can be realized. And comparing with the traditional vibrating screen, its screening efficiency and capacity are greatly improved. This new kind vibrating screen is especially suitable for the dry screening to moist particles.

Research on the Performance of Ultrasonic Vibration Assisted Electrical Discharge Surface Modification Layer

2010 ◽  
Vol 171-172 ◽  
pp. 408-411
Author(s):  
Chun Jie Dong ◽  
Jian Hua Zhang ◽  
Xi Chao Song
Keyword(s):  
Surface Roughness ◽  
Wear Resistance ◽  
Surface Modification ◽  
Ultrasonic Vibration ◽  
Electrical Discharge ◽  
Vibration Amplitude ◽  
Experimental Results ◽  
Tool Electrode ◽  
Micro Hardness ◽  
Melting Material

Ultrasonic vibration assisted electrical discharge surface modification was studied in the paper. The influence of ultrasonic vibration amplitude and frequency on the modification layer performance, such as surface roughness, sectional morphology, micro hardness and wear resistance was investigated. Experimental results show that ultrasonic vibration assisted electrical discharge surface modification can improve surface roughness and make the melting material well-distributed. The surfaces have higher micro hardness and wear resistance when the tool electrode is assisted with ultrasonic vibration.

Effects of Combined Ultrasonic Vibration during the Sinking EDM Process for Cemented Carbide

2009 ◽  
Vol 76-78 ◽  
pp. 657-663 ◽  
Author(s):  
Chaiya Praneetpongrung ◽  
Yasushi Fukuzawa ◽  
Shigeru Nagasawa
Keyword(s):  
Surface Roughness ◽  
Ultrasonic Vibration ◽  
Material Removal Rate ◽  
Electrical Discharge ◽  
Material Removal ◽  
Removal Rate ◽  
Cemented Carbide ◽  
Electrode Wear ◽  
Machining Properties ◽  
Edm Process

In recent years, to improve the electrical discharge machining properties, several trials have been applied with the ultrasonic vibration system which was combined on the sinking electrical discharge machine. In this paper, the effects of the ultrasonic vibration were investigated with the designed sinking EDM machine. Some experimental parameters of tool electrode polarity, rotational workpiece speed and directions were examined during the sinking EDM process on the cemented carbide material of G5. Material removal rate, electrode wear ratio and surface roughness were estimated as the machining properties under finishing machining conditions. The experiments were carried out on ultrasonic longitudinal frequency 59 kHz and electrode spindle till 1,000 rpm. Two rotational apparatuses were used simultaneously on the opposite rotational direction during discharge machining. The discharge conditions were estimated with the waveforms analysis. As the results, the EDM device system which was combined ultrasonic vibration, improved the material removal rate and surface roughness of the EDMed workpiece.

Simulations of high-resolution images of amorphous silicon films

1986 ◽  
Vol 44 ◽  
pp. 544-545
Author(s):  
G. Y. Fan ◽  
J. M. Cowley
Keyword(s):  
Electron Microscope ◽  
High Frequency ◽  
Fourier Transformation ◽  
Amorphous Materials ◽  
Low Frequency ◽  
Chromatic Aberration ◽  
Structure Information ◽  
Frequency Components ◽  
High Resolution Images ◽  
Spatial Frequency Spectrum

It is well known that the structure information on the specimen is not always faithfully transferred through the electron microscope. Firstly, the spatial frequency spectrum is modulated by the transfer function (TF) at the focal plane. Secondly, the spectrum suffers high frequency cut-off by the aperture (or effectively damping terms such as chromatic aberration). While these do not have essential effect on imaging crystal periodicity as long as the low order Bragg spots are inside the aperture, although the contrast may be reversed, they may change the appearance of images of amorphous materials completely. Because the spectrum of amorphous materials is continuous, modulation of it emphasizes some components while weakening others. Especially the cut-off of high frequency components, which contribute to amorphous image just as strongly as low frequency components can have a fundamental effect. This can be illustrated through computer simulation. Imaging of a whitenoise object with an electron microscope without TF limitation gives Fig. 1a, which is obtained by Fourier transformation of a constant amplitude combined with random phases generated by computer.

SEM image sharpness analysis

1996 ◽  
Vol 54 ◽  
pp. 142-143
Author(s):  
M. T. Postek ◽  
A. E. Vladar
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Quantitative Information ◽  
Primary Electron ◽  
Image Sharpness ◽  
Critical Dimensions ◽  
Sem Image ◽  
Frequency Changes ◽  
Electron Microscopes ◽  
Scanning Electron

Fully automated or semi-automated scanning electron microscopes (SEM) are now commonly used in semiconductor production and other forms of manufacturing. The industry requires that an automated instrument must be routinely capable of 5 nm resolution (or better) at 1.0 kV accelerating voltage for the measurement of nominal 0.25-0.35 micrometer semiconductor critical dimensions. Testing and proving that the instrument is performing at this level on a day-by-day basis is an industry need and concern which has been the object of a study at NIST and the fundamentals and results are discussed in this paper.In scanning electron microscopy, two of the most important instrument parameters are the size and shape of the primary electron beam and any image taken in a scanning electron microscope is the result of the sample and electron probe interaction. The low frequency changes in the video signal, collected from the sample, contains information about the larger features and the high frequency changes carry information of finer details. The sharper the image, the larger the number of high frequency components making up that image. Fast Fourier Transform (FFT) analysis of an SEM image can be employed to provide qualitiative and ultimately quantitative information regarding the SEM image quality.

Real Ear Sound Pressure Levels Developed by Three Portable Stereo System Earphones

1992 ◽  
Vol 1 (4) ◽  
pp. 52-55 ◽  
Author(s):  
Gail L. MacLean ◽  
Andrew Stuart ◽  
Robert Stenstrom
Keyword(s):  
High Frequency ◽  
Sound Pressure ◽  
Low Frequency ◽  
Test System ◽  
Output Frequency ◽  
Frequency Effects ◽  
Adult Men ◽  
Frequency Responses ◽  
Significant Difference ◽  
Sound Pressure Levels

Differences in real ear sound pressure levels (SPLs) with three portable stereo system (PSS) earphones (supraaural [Sony Model MDR-44], semiaural [Sony Model MDR-A15L], and insert [Sony Model MDR-E225]) were investigated. Twelve adult men served as subjects. Frequency response, high frequency average (HFA) output, peak output, peak output frequency, and overall RMS output for each PSS earphone were obtained with a probe tube microphone system (Fonix 6500 Hearing Aid Test System). Results indicated a significant difference in mean RMS outputs with nonsignificant differences in mean HFA outputs, peak outputs, and peak output frequencies among PSS earphones. Differences in mean overall RMS outputs were attributed to differences in low-frequency effects that were observed among the frequency responses of the three PSS earphones. It is suggested that one cannot assume equivalent real ear SPLs, with equivalent inputs, among different styles of PSS earphones.

Evaluation of Special Hearing Aids for Deaf Children

1971 ◽  
Vol 36 (4) ◽  
pp. 527-537 ◽  
Author(s):  
Norman P. Erber
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Hearing Aid ◽  
Low Frequency ◽  
Acoustic Stimulation ◽  
Deaf Children ◽  
Frequency Range ◽  
Frequency Limit ◽  
Unpublished Studies ◽  
Published Research

Two types of special hearing aid have been developed recently to improve the reception of speech by profoundly deaf children. In a different way, each special system provides greater low-frequency acoustic stimulation to deaf ears than does a conventional hearing aid. One of the devices extends the low-frequency limit of amplification; the other shifts high-frequency energy to a lower frequency range. In general, previous evaluations of these special hearing aids have obtained inconsistent or inconclusive results. This paper reviews most of the published research on the use of special hearing aids by deaf children, summarizes several unpublished studies, and suggests a set of guidelines for future evaluations of special and conventional amplification systems.

Efeitos do Método Pilates sobre a variabilidade da frequência cardíaca, flexibilidade e variáveis antropométricas em indivíduos sedentários

2016 ◽  
Vol 17 (1) ◽  
pp. 66
Author(s):  
Maria Lina Silva Leite
Keyword(s):  
High Frequency ◽  
Low Frequency

O objetivo deste estudo foi avaliar os efeitos do Método Pilates sobre a variabilidade da frequência cardíaca, na flexibilidade e nas variáveis antropométricas em indivíduos sedentários. O presente estudo contou com 14 voluntárias do sexo feminino, na faixa etária entre 40 e 55 anos, que realizaram 20 sessões de exercícios do Método Pilates, duas vezes por semana, com duração de 45 minutos cada sessão, dividida em três fases: repouso, exercício e recuperação. As variáveis estudadas foram: os dados antropométricos, flexibilidade avaliada utilizando o teste de sentar-e-alcançar com o Banco de Wells, e intervalos R-R usando um cardiotacômetro. O processamento dos sinais da frequência cardíaca foi efetuado em ambiente MatLab 6.1®, utilizando a TWC. Os dados coletados foram submetidos ao teste de normalidade de Shapiro Wilk e foi utilizado o teste de Wilcoxon e Anova One Way (α = 0,05). Nos resultados, observou-se que não houve diferenças significativas entre os valores antropométricos e de frequência cardíaca, porém houve aumento da flexibilidade com o treinamento. Comparando a primeira e a vigésima sessão com relação aos parâmetros low frequency (LF), high frequency (HF), e relação LF/HF, não houve diferença na fase de repouso e foram constatadas diferenças significativas de LF (p = 0,04) e HF (p = 0,04) na fase de exercício e diferença significativa de LF/HF (p = 0,05) na fase de recuperação. Comparando os parâmetros nos períodos de repouso, exercícios e recuperação durante a primeira sessão e durante a vigésima sessão, não houve diferença significativa nos parâmetros LF, HF e LF/HF. Pode-se concluir que, em relação à flexibilidade, foi observada uma melhora significativa, enquanto a análise da frequência cardíaca caracterizou a intensidade do exercício de 50% da capacidade funcional das voluntárias. Em relação aos parâmetros LF, HF e LF/HF foram observados um aumento da variabilidade da frequência cardíaca, provavelmente produto da atividade do Método Pilates. A Transformada Wavelet (TWC) mostrou-se um Método adequado para as análises da variabilidade da frequência cardíaca.Palavras-chave: frequência cardíaca, Transformada Wavelet, Pilates.

Dynamics of the processes in metal machining

1998 ◽  
Vol 2 ◽  
pp. 115-122
Author(s):  
Donatas Švitra ◽  
Jolanta Janutėnienė
Keyword(s):  
High Frequency ◽  
Machine Tools ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Low Frequency ◽  
Metal Cutting Machine ◽  
Cutting Machine ◽  
Metal Machining

In the practice of processing of metals by cutting it is necessary to overcome the vibration of the cutting tool, the processed detail and units of the machine tool. These vibrations in many cases are an obstacle to increase the productivity and quality of treatment of details on metal-cutting machine tools. Vibration at cutting of metals is a very diverse phenomenon due to both it’s nature and the form of oscillatory motion. The most general classification of vibrations at cutting is a division them into forced vibration and autovibrations. The most difficult to remove and poorly investigated are the autovibrations, i.e. vibrations arising at the absence of external periodic forces. The autovibrations, stipulated by the process of cutting on metalcutting machine are of two types: the low-frequency autovibrations and high-frequency autovibrations. When the low-frequency autovibration there appear, the cutting process ought to be terminated and the cause of the vibrations eliminated. Otherwise, there is a danger of a break of both machine and tool. In the case of high-frequency vibration the machine operates apparently quiently, but the processed surface feature small-sized roughness. The frequency of autovibrations can reach 5000 Hz and more.

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