Terms frequently used in Circular Geometry Inspection
BS-3730, ISO-1101, and ISO-6318 - These are the British and International standards for "Measurement of departures from roundness." Turbine Metrology's Paragon system conforms to these standards.
16 bit analog to digital conversion - Any analog-to-digital (A-D) converter's accuracy rating is based on taking an average of several thousand samples for each conversion. "16 bit" systems which have the speed to take only one or two samples prior to conversion cannot achieve true 16 bit accuracy (1 part in 65,536). Paragon's Data Acquisition System can take up to 153,600 readings per channel per second, allowing sufficient oversampling to achieve rated accuracy and beyond.
Anti-aliasing filters - Digital filtering algorithms will create errors in the data ("alias") if the sampling speed of the DAS is less than 2.5 times (approximately) the frequency of the signal being filtered. This is referred to as the "Nyquist" frequency. Paragon's DAS can sample at up to 153,600 readings per second, allowing its on-board digital signal processors to filter frequencies far above the reach of other systems without creating errors in the data. This is one reason why Paragon can achieve such high accuracy in shop floor environments of high ambient noise and vibration. These filters have even proven effective in eliminating RFI from radio controlled overhead cranes.
Concentricity - In the relationship of two diameters, the deviation of the mean center of one surface from the mean center of the reference surface (datum).
Digital Signal Processing (DSP) - The easiest way to keep anomolous data from skewing the results is to keep the bad readings from entering the data stream in the first place. Due to the tremendous speed of the Paragon data acquisition hardware, and computer-within-a-computer design, DSP is used to insure the integrity of the incoming signals. Removal of anomolous readings data from the data set is not required as errors were not allowed into the data from the beginning.
Eccentricity - The deviation of one diameter from circular.
Flatness - The deviation of one face from a plane.
Internal database - The stand-alone (non-networked) version of Paragon contains an Oracle database for the storage of data. Paragon stores 3600 points of data on each measured surface of each part. This data may be retrieved at any later date for comparison, re-analysis, plotting, or display.
Inspection Table - The mechanical stage on which the tested part is rotated to obtain measurements. Inspectation tables usually have air bearing thrust surfaces and either an air or mechanical radial bearing. Inspection tables must rotate with extreme accuracy and stability to avoid influincing the measurement of the part being tested. TM's Paragon systems use tables purpose built by Eimeldingen technology.
Network capability - Users with multiple Paragon installations may choose to network the systems through a server to a common Oracle database.
Off-centeredness - No matter how carefully a part is placed on the inspection table, the part's center can never be exactly in line with the table's rotational axis. This off-centeredness will show up as runout of the part diameters unless a mathematical algorithm is available to recognize and remove the off-centeredness. Other systems use algorithms which do not remove this error accurately due to distortion of the data during sampling. Paragon uses a unique combination of algorithms which removes the off-centeredness without distorting the data.
Oversampling - The number of readings taken at one location on a part. These readings are averaged to obtain the final value. the higher number of readings the more representative the result will be as the effects of noise, vibration, Analog-to-Digital conversion aperature jitter and quantizing errors and other extraneous errors are minimized.
Parallelism - In the relationship of two faces, the deviation of the mean plane of one surface from the mean plane of the reference surface (datum). Similar to Concentricity.
Runout - In either faces or diameters, the maximum excursion of the surface.
Simultaneous sampling - Due to the rotation of the inspection table, the relationship of the part surfaces can be accurately analyzed only if the measurements of the surfaces are taken at exactly the same time. Paragon uses simultaneous sampling; many systems do not.
Windows 2000/XP - Paragon uses standard familar Microsoft Windows operating systems, allowing other Customer software packages to run in conjunction with Paragon.
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