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Shanmugaraj, V.
- On-Line Detection and Identification of Faults and Abnormalities in Sensors for Ultra Precision Process Monitoring
Abstract Views :157 |
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Authors
Affiliations
1 Central Manufacturing Technology Institute, Bangalore, IN
1 Central Manufacturing Technology Institute, Bangalore, IN
Source
Manufacturing Technology Today, Vol 13, No 7 (2014), Pagination: 13-19Abstract
In Ultra precision machining best results are obtained with on-line monitoring and adaptive control of various process parameters during machining. For a reliable on-line process monitoring and error compensation system, it is necessary to have accurate sensor readings. However, sometimes sensors may become faulty and due to failure it gives erroneous or constant values throughout the process. The problem of sensor validation is therefore a critical part of effective process monitoring. The objective of this study is to develop a sensor fault detection module which will be useful for different error compensation /diagnostic techniques needed for the ultra precision machine. A procedure based on Principal Component Analysis (PCA) is developed, which enables to perform detection and identification of sensor failures. PCA is a data driven modelling that transforms a set of correlated variables into a smaller set of new variables (principal components) that are uncorrelated and retain most of the original information. This new index is proposed in order to detect simple and multiple faults affecting the process and diagnose abnormalities in the original system in a robust way. The PCA model maps the sensor variables into a lower dimensional space and tracks their behaviour using Hot teling T2 and Q statistics.Keywords
PCA, Scores, Faulty Sensor, HottelingT2, Artificial Drifts, Q Statistics.- Measurement of Straightness of High Aspect Ratio Thick Walled Cylinder-A Concept
Abstract Views :173 |
PDF Views:0
Authors
Affiliations
1 Central Manufacturing Technology Institute, Bangalore, IN
1 Central Manufacturing Technology Institute, Bangalore, IN
Source
Manufacturing Technology Today, Vol 11, No 1-2 (2012), Pagination: 5-10Abstract
Productivity in manufacture of high aspect ratio cylinders depends on how quickly the inspection parameters are measured and corrective actions are token. Long cylinders undergo a series of processes including bend removal and machining. These processes undergo a series of iterations consuming considerable amount of time for the measurement of straightness of cylinder. In this paper, a concept is proposed, where, the straightness of the bore of a cylinder (barrel) is measured in-situ on the machine. In this method, the barrel diameter and thickness are measured at number of planes using touch trigger probe and ultrasonic transducer respectively. Ultrasonic transducer assembly and the touch trigger probe are mounted on the turret of the CNC Turn Mill Centre. The setup for ultrasonic based measurement includes a nozzle for the supply of stream of liquid on the work piece, an ultrasonic transducer and a data capturing unit. Echo from ultrasonic waves is obtained back from the stream enabling the measurement of the relative position from the outer profile of the work piece to its internal profile. By orienting (rotating) the work piece at different locations in the same plane, thickness and diameters are measured. Straightness is measured by continuing to measure along the length of the cylinder. The thickness and diameters obtained are then used for the evaluation of straightness of the bore.Keywords
Straightness, Cylinder, Touch Trigger Probe, Ultrasonic Transducer.- Study of Thermal Behaviour in a Machine Tool using Ansys
Abstract Views :161 |
PDF Views:0
Authors
Affiliations
1 Karunya Institute of Technology and Science, Karunya Nagar, Coimbatore, IN
2 Central Manufacturing Technology Institute, Bangalore, IN
1 Karunya Institute of Technology and Science, Karunya Nagar, Coimbatore, IN
2 Central Manufacturing Technology Institute, Bangalore, IN