Real-time parameterization of electrochemical machining by ultrasound measurement of the interelectrode gap

2007 ◽  
Vol 221 (4) ◽  
pp. 551-558 ◽  
Author(s):  
R N Muir ◽  
D R Curry ◽  
F Mill ◽  
A Sherlock ◽  
A R Mount
Keyword(s):  
Real Time ◽  
Electrochemical Machining ◽  
Ultrasound Measurement ◽  
Interelectrode Gap

scholarly journals Real-time non-invasive intracranial state estimation using unscented Kalman filter

2018 ◽  
Author(s):  
Chanki Park ◽  
Seungjun Ryu ◽  
Bonghyun Jung ◽  
Sangpyong Lee ◽  
Changkie Hong ◽  
...  
Keyword(s):  
Real Time ◽  
Unscented Kalman Filter ◽  
Transcranial Doppler Ultrasound ◽  
Ultrasound Measurement ◽  
Icp Monitoring ◽  
Non Invasive ◽  
Severance Hospital ◽  
Arterial Blood ◽  
Clinical Conditions ◽  
Increased Icp

AbstractIntracranial pressure (ICP) monitoring is desirable as a first-line measure to assist decision-making in cases of increased ICP. Clinically, non-invasive ICP monitoring is also required to avoid infection and hemorrhage in patients. The relationships among the arterial blood pressure (Pa), ICP, cerebral blood flow, and its velocity (QCBFv) measured by transcranial Doppler ultrasound measurement have been reported. However, real-time non-invasive ICP estimation using these modalities is less well documented. Here, we present a novel algorithm for real-time and non-invasive ICP monitoring with QCBFv and Pa, called direct-current (DC)-ICP. This technique is compared with invasive ICP for 11 traumatic-brain-injury patients admitted to Cheju Halla Hospital and Gangnam Severance Hospital from July 2017 to June 2018. The inter-subject correlation coefficient between true and estimate was 0.70. The AUCs of the ROCs for prediction of increased ICP for the DC-ICP methods are 0.816. Thus, QCBFv monitoring can facilitate reliable real-time ICP tracking with our novel DC-ICP algorithm, which can provide valuable information under clinical conditions.

scholarly journals Dynamic Observer Modeling and Minimum-Variance Self-Tuning Control of EDM Interelectrode Gap

2018 ◽  
Vol 8 (9) ◽  
pp. 1443 ◽  
Author(s):  
Bin Xin ◽  
Shujuan Li ◽  
Xincheng Yin ◽  
Xiong Lu
Keyword(s):  
Real Time ◽  
Physical Model ◽  
Short Circuit ◽  
Single Crystal Silicon ◽  
Minimum Variance ◽  
Machining Process ◽  
Crystal Silicon ◽  
Interelectrode Gap ◽  
Self Tuning ◽  
The Time Domain

The electric discharge machining (EDM) interelectrode gap directly determines the discharge state, which affects the machining efficiency, workpiece surface quality, and the tool wear rate. The measurement of the real-time varying interelectrode gap during machining is extremely difficult, and so obtaining an accurate mathematical model of the dynamic interelectrode gap will make EDM gap control possible. Based on p-type single-crystal silicon EDM, a flat-plate capacitance model is introduced to analyze the time-domain characteristics of the inter-electrode voltage in the breakdown delay phase. Further, we theoretically established a physical model of the interelectrode spacing d and the charging time constant τ of the plate capacitor. The least-squares fitting of the experimental data was used to determine the model coefficients, and in combination with the actual machining process, a minimum-variance self-tuning controller was designed to control the interelectrode gap in real time. The experimental verification results show that the established physical model can correctly predict the interelectrode gap in the actual machining process. The minimum-variance self-tuning controller improves machining stability, and eliminates the occurrence of the short-circuit state.

scholarly journals Reliability of Diaphragmatic Mobility Assessment Using a Real Time Ultrasound Among Non-Specific Low Back Pain.

2017 ◽  
Vol 16 (3) ◽  
pp. 443-447 ◽  
Author(s):  
Vikram Mohan ◽  
Ummi Farhana Hashim ◽  
Sulaiman Md Dom ◽  
Patraporn Sitilerpisan ◽  
Aatit Paungmali
Keyword(s):  
Low Back Pain ◽  
Back Pain ◽  
Real Time ◽  
Medical Science ◽  
Ultrasound Measurement ◽  
Measurement Tool ◽  
Low Back ◽  
Rater Reliability ◽  
Mobility Assessment ◽  
The Right

Background and Objective: Ultrasound measurement of Diaphragmatic Mobility (DM) has been shown to be a reliable measurement tool among healthy subjects. However, the measures of reliability are needed prior to clinical use of this device among Non-Specific Low Back Pain (NS-LBP). Therefore, the aim of the study was to investigate the relative and absolute reliability of DM using Real Time Ultrasound (RTUS) among subjects with NS-LBP.Materials and Methods: Nine subjects with NS-LBP (23.33 ± 1.58) years old were recruited. A qualified examiner performed measurement of DM using RTUS by placing transducer on the right subcostal region in semi-fowler’s position with 30 degree elevation of the trunk. The test-retest measures were re-assessed with 24 hour interval between sessions.Results: There was no systematic errors between the test-retest measures (p>0.05). Intra rater reliability showed ICC value of 0.92, which indicates an excellent reliability. The SEMs of the measurement was 2.56 mm and the MDC of 7.09mm.Conclusion:The RTUS for assessing DM provides an excellent intra-rater reliability which may be used as an assessment technique for clinical evaluation of DM in adults with NS-LBP. The SEMs and MDC reported may also allow for accurate interpretation of DM assessments in NS-LBP.Bangladesh Journal of Medical Science Vol.16(3) 2017 p.443-447

System Design and Experiments of Tool Setting Detection in Micro-Electrochemical Machining Based on LabVIEW

2016 ◽  
Vol 693 ◽  
pp. 1693-1697
Author(s):  
P.Y. Dong ◽  
Zhi Yong Li ◽  
Hong Bin Cui ◽  
J.J. Sun
Keyword(s):  
System Design ◽  
Real Time ◽  
Detection System ◽  
Electrochemical Machining ◽  
Workpiece Material ◽  
Positioning Accuracy ◽  
Erosion Rates ◽  
Micro Ecm ◽  
Tool Setting ◽  
Accuracy And Repeatability

The initial gap in electrochemical machining (ECM) is a significant affection parameter for ECM process and machining stability. A tool setting detection system based on LabVIEW technology has been designed to realize the rapid and accurate pinpoint between two electrodes since the initial gap of micro-ECM is usually only a few microns to tens of microns. The system can not only efficiently complete tool setting detection in micro-ECM, but also real-time monitor the change of processing current. 120 comparative experiments have been conducted to evaluate the erosion amount of workpiece material, the reliability, repeatability and positioning accuracy of micro-ECM process in the conditions of wet tool setting compared with dry tool setting. The experimental results have shown that adopting the tool setting detection system designed in this paper, the erosion rates of cathode and anode after 120 repeated wet tool setting experiments were only 0.21% and 0.02%, the positioning accuracy and repeatability can completely meet the requirements of tool setting in micro-ECM, and greatly improve the efficiency of the micro-ECM.

Modelling and Analysis of Pulse Electrochemical Machining (PECM)

1994 ◽  
Vol 116 (3) ◽  
pp. 316-323 ◽  
Author(s):  
J. Kozak ◽  
K. P. Rajurkar ◽  
B. Wei
Keyword(s):  
Anodic Dissolution ◽  
Experimental Studies ◽  
Electrochemical Machining ◽  
Dimensional Accuracy ◽  
Tool Design ◽  
Machining Parameters ◽  
Electrolyte Flow ◽  
Pulse Electrochemical Machining ◽  
Interelectrode Gap ◽  
Continuous Current

A small interelectrode gap in Electrochemical Machining (ECM) results in improved dimensional accuracy control and simplified tool design. However, using a small gap with conventional ECM equipment adversely affects the electrolyte flow or mass transport conditions in the gap, leading to process instability. The most remarkable breakthrough in this regard is the development of ECM using pulsed current. Pulse Electrochemical Machining (PECM) involves the application of a voltage pulse at high current density in the anodic dissolution process. PECM allows for more precise monitoring and control of machining parameters than ECM using continuous current. Small interelectrode gap, low electrolyte flow rate, gap state recovery during the pulse-off times and improved anodic dissolution efficiency features encountered in PECM lead to improved workpiece precision and surface finish when compared with ECM using continuous current. This paper presents mathematical models for the PECM process which take into consideration the nonsteady physical phenomena in the gap between the electrodes, including the conjugate fields of electrolyte flow velocities, pressure, temperature, gas concentrations, current densities and anodic material removal rates. The principles underlying higher dimensional accuracy and simpler tool design attainable with optimum pulse parameters are also discussed. Experimental studies indicate the validity of the proposed PECM models.

A theoretical analysis of electrochemical arc machining

1990 ◽  
Vol 429 (1877) ◽  
pp. 429-447 ◽  
Keyword(s):  
Current Efficiency ◽  
Current Density ◽  
Electrochemical Machining ◽  
Approximate Solutions ◽  
Hole Drilling ◽  
Metal Loss ◽  
Interelectrode Gap ◽  
Surface Irregularities ◽  
Gap Width ◽  
Lower Loss

Electrochemical arc machining (ECAM) involves the removal of metal from an anodically polarized workpiece by both erosion arising from discharges produced in an aqueous electrolyte and electrolytic dissolution. A theoretical model is derived for the process and analysed for two specific applications, fine-hole drilling and the finishing of components by smoothing of their initially rough surfaces. In the second of these examples, a perturbation procedure for obtaining approximate solutions is used; the model so developed encorporates the effects of current density on current efficiency which are known from experimental electrochemical machining (ECM) studies to influence the rate and mode of smoothing. For fine-hole drilling by ECAM, the analysis predicts that the interelectrode gap width increases with the applied voltage and inversely with the square root of the mechanically driven anode. In the case of smoothing, ECAM is found to remove the surface irregularities at a much faster rate and with lower loss of stock metal than ECM alone, when electrolytes such as sodium chloride solution yielding 100% current efficiency are used for the latter process. The analysis shows that an electrolyte solution with a current density-dependent current efficiency is needed if parent metal loss by ECM is to approach that of ECAM, and even then, machining by the latter is still much faster. Attention is drawn to experimental evidence in support of these predictions of ECAM behaviour. Finally, results from the model are used to verify the practical use of ECM for rapid finishing of the surfaces of components left rough by electrodischarge machining.

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