Tribology

Tribology is the science and study that involves understanding the principles of friction, lubrication and wear in engines, turbine, and gear boxes.  Evaluating the composition, size distribution, and shape of foreign particles is the primary goal in control contamination.

 

From a knowledge of the elemental composition of the steels, lubricants, and coating materials present within the wear environment, one can better evaluate and understand from what internal parts the various particle are being generated, confidently leading one on course with the best available diagnostic data! Having the ability to monitor such quantities over time can guide insight on the rapidity of wear, how and when to intervene, and through better documentable findings, pinpoint the changes in question to better evaluate part replacement, overall engine, gearbox or turbine health, and the assumptions to liability.

 

Automating the analysis and report writing for such processes, through the use of the ASPEX technology, can lead to great costs savings, while simultaneously increasing routine to complex failure mode assessments, leading to better recommendation, confidence and feed back for your clients. 


 

The ASPEX Systems use a surprisingly compact single hardware control configuration for both the SEM and EDX components resulting in faster integrated analysis times. Unlike frame-based systems, the dynamic scan control in the ASPEX Systems use "stage fields" that are further subdivided into “mag fields". The "mag fields” represent individually subdivided array regions that are defined purely by deflection of the electron beam.  As a result, movement between fields is done electronically, as opposed to slower frame-based system movements that mechanically advance the stage. Instead of capturing a high resolution image of the frame, the ASPEX moves the beam across the full field through a sequential array of fairly coarse steps. The smaller electron beam focal spot then scans rigorously across each "mag field" and a particle is detected when the BSE intensity level of the particle exceeds the predefined threshold background set for each analysis activity (pre-set or and/or user defined at install).  This particle-sizing sequence initiates a "rotating chord" algorithm to measure the particle.  At a 2048 pixel resolution, a series of chords are drawn through the center of the particle at equal angular spacing's. Particle size and shape measurements are derived from the chords.  All variables are collected for each particle. Figure 1 illustrates the dynamic scan and rotating chord algorithm sequence along with the flow and output expectation.

 

 

After the particle is detected and measured, an energy dispersive X-ray spectrum is acquired at the center perimeter, or along each chord for every particle detection event.  Once the particle is characterized (size, shape and elemental composition) user­ defined rules place them into a "class". If needed, the particles can be relocated and further examined by the operator. The ASPEX System further provides a customizable reporting tool that automatically generates reports of the analyses targets.  In addition, a database stores all results of analyses for use in monitoring long term processing trends and comparative post processing data mining.  All previous analyses can be reanalyzed with new rule classification and elemental vector sets at any future point.

 

 

SYSTEM DESCRIPTION:

The ASPEX System is a compact, rugged, cost effective, and fully integrated automated scanning electron microscope (SEM) designed for high speed particle analysis in any environment.  The ASPEX Explorer TM includes a secondary electron detector (SED) and a backscattered electron (BSE) detector for imaging, integrated with a silicon drift detector (SDD) for energy dispersive X-ray spectroscopy (EDX). The system provides both high vacuum and variable pressure modes for characterization and assessment of a variety of oil particle analysis profiles and elemental composition patterns.  The chamber has a stage that accommodates a choice of removable, interchangeable, and customizable sample holders.  The built in vibration isolation system and the standard 110V operation allows for operation at diverse locations without modification.

 

System Operation and Functionality - How does it work?

The ASPEX Systems use a surprisingly compact single hardware control configuration for both the SEM and EDX components resulting in faster integrated analysis times.  Unlike frame-based systems, the dynamic scan control in the ASPEX Systems use “stage fields” that are further subdivided into “mag fields”.  The “mag fields” represent individually subdivided array regions that are defined purely by deflection of the electron beam.  As a result, movement between fields is done electronically, as opposed to slower frame-based system movements that mechanically advance the stage.  Instead of capturing a high resolution image of the frame, the ASPEX moves the beam across the full field through a sequential array of fairly coarse steps. The smaller electron beam focal spot then scans rigorously across each “mag field” and a particle is detected when the BSE intensity level of the particle exceeds the predefined threshold background set for each analysis activity (pre-set or and/or user defined at install).  This particle-sizing sequence initiates a “rotating chord” algorithm to measure the particle.  At a 2048 pixel resolution, a series of chords are drawn through the center of the particle at equal angular spacing’s.  Particle size and shape measurements are derived from the chords.  All variables are collected for each particle.  Figure 1 illustrates the dynamic scan and rotating chord algorithm sequence along with the flow and output expectation.


After the particle is detected and measured, an energy dispersive X-ray spectrum is acquired at the center, perimeter, or along each chord for every particle detection event.  Once the particle is characterized (size, shape and elemental composition) user-defined rules place them into a “class”.  If needed, the particles can be relocated and further examined by the operator.  The ASPEX System further provides a customizable reporting tool that automatically generates reports of the analyses targets.  In addition, a database stores all results of analyses for use in monitoring long term processing trends and comparative post processing data mining. All previous analyses can be reanalyzed with new rule classification and elemental vector sets at any future point.


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