Original Date: 03/01/1993
Revision Date: 01/18/2007
Information : Replacement for Replication Metallography
Naval Aviation Depot (NADEP), Jacksonville successfully applied an old technology to today's high technology environment with outstanding results, while providing an example of technology transfer from one industry to another. NADEP, Jacksonville purchased a small portable microscope - or Rollscope - manufactured by Unitron for use in aerospace maintenance. The microscope, with an initial cost of approximately $1,500, was originally designed for in-situ metallographic examination of large diameter printing rolls.
Conventional replication metallography is normally used to address problems requiring metallographic examination where the item is too large or heavy for an ordinary microscope, or where NDI is required. Replication metallography involves careful polishing of the area, etching to reveal the structure, and replication of the microstructure by applying acetate film or tape that has been softened with acetone. After drying, the replica is carefully peeled away and transferred to a conventional microscope for examination. This process is tedious and time consuming.
The Rollscope portable microscope can be used for parts requiring non-destructive microstructural analysis. Examination involves preparation (polishing) of the area, then etching followed by direct microscopic inspection. The Rollscope uses an attached camera for photographing items. In-situ metallographic examination with the Rollscope is easier and faster than conventional replication techniques and produces better images, allowing for more precise analysis.
NADEP, Jacksonville has successfully applied use of this microscope to a variety of aerospace maintenance issues including grain size measurements of the TF-34 fan shaft, grain size measurements of the J-52 second stage turbine outer air seal, and for defect interpretation on P-3 landing gear pistons. In most instances, Rollscope metallography can be used in lieu of replication.
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