Welcome High Speed Video for Spin Testers
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ExamplesHigh Speed VideoStandard spin pit burst testing is primarily done to establish a speed, above the operating and over-speeds, at which point the rotating assembly fails due to centrifugal stress. Customers need the failure speed to determine the safety margin during normal operation. A standard burst test provides only the failure speed and does not supply any additional information about which section of the test article initiated the failure or how it failed. Test Devices offers customers the option of a high speed video recording of the failure event, to provide additional data. These videos can often be critically important to designers in determining what failed first in the rotating assembly. Often, within the first slow motion play back of the burst event, customers are able to determine if the rim or bore section of the test rotor began the burst event. TDI high speed videos also benefit the failure analysis process, following burst tests. Metallurgical engineers are able to quickly hone in on the critical pieces of the burst fragments to direct their examination. As part of the high speed video process Test Devices offers an optional coating scheme which can accentuate the clarity of the video. A patterned coating applied to the disk surface provides reference points, which are visible on the video, benefiting the post-test analysis process. This process is particularly useful for burst testing disks which are homogeneous, by providing landmarks for correlation between burst video and post-test analysis. EquipmentTest Devices uses a Kodak Motion Analyzer System to capture the high-speed burst events that occur during spin testing. The Motion Analyzer System is a digital video camera that uses a laser illuminator to take pictures at rates up to 40,000 frames/sec. Unlike a film camera (stop action photography), the digital camera takes pictures continuously, overwriting its memory when it gets to the end of the picture buffer. In addition, the test engineer can trigger the system anywhere in memory, instructing the camera to save the last N frames before continuing to the end of the picture buffer. This allows the test engineer to capture and save visual history PRIOR to the trigger event. Test Devices uses an Oxford Laser system as an illuminator for high-speed photography, instead of relying on a mechanical shutter. Resolution of the camera ranges from 256 x 256 (8-bit pixels) to 64 x 64, depending on the frame rate. The camera is positioned below the bottom of the spin chamber, using a bullet-proof glass view-port to provide a clear view of the spinning rotor inside the chamber. The laser light source is also introduced through the bottom of the spin chamber through a view-port. In Example 1, a series of photos taken from High Speed Video was taken of a Burst Test performed on a cast part. The test casting was spinning at 5,000 rpm. Example 2 shows a similar series of photos taken from High Speed Video performed on a molded fan spinning at 6,000 rpm. Example 3 shows a Burst Test performed on an aluminum impeller spinning at 40,000 rpm. Note: These photos have been intentionally degraded to protect customer detail. (Full size sample [Internet Explorer only])
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Example 1
Example 2
Example 3 Note: These photos have been intentionally degraded to protect customer detail. |
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