REG NASA-LLIS-0846-2000 Lessons Learned Wear Particle Analysis Using Ferrography.pdf

1、Best Practices Entry: Best Practice Info:a71 Committee Approval Date: 2000-04-20a71 Center Point of Contact: KSCa71 Submitted by: Wil HarkinsSubject: Wear Particle Analysis Using Ferrography Practice: Use Ferrography to diagnose equipment problems and predict equipment failure before it occurs.Progr

2、ams that Certify Usage: This practice has been used on KSC Payload Facility Crane Gear Reducers.Center to Contact for Information: KSCImplementation Method: This Lesson Learned is based on Maintainability Technique number AT-6 from NASA Technical Memorandum 4628, Recommended Techniques for Effective

3、 Maintainability.Benefit:Ferrography provides early detection of abnormal wear of the lubricated critical internal components of mechanical systems. Analyzes the debris in system lubricants. Shows particle size, shape and color as well as quantity. Reveals which system component is wearing, and to w

4、hat degree, and pinpoints the cause of the wear.Implementation Method:Ferrography is a very useful and comprehensive analysis for trending and reporting. At a minimum, Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-the user can obtain an analytical

5、means of monitoring the wear condition; and, at the same time, accrue the necessary sample points required to establish a wear particle concentration baseline and retain the presence of non-magnetic particles for visual inspection and evaluation.The advantage of Ferrography over other preventive mai

6、ntenance systems is its capacity to detect a broader range of types and sizes (0.1-500 microns) of wear particles. A micron is one millionth of a meter. Ferrographic analysis encompasses wear (metallic and non-metallic), contaminant (crystals, water, and organic and inorganic compounds), and lubrica

7、nt (friction polymers) monitoring.Typical wear problems identified by Ferrography; gear teeth wear through excessive load or speed, misalignments, fractures, rolling contact failure, water in the oil or poor lubricant condition, oil additive depletion, outside contaminants such as sand or dust, cam

8、shaft and cylinder wall failure, oil filter failure. There are many others.Industrial application of Ferrography entails the non-interruptive machine condition monitoring of heavily used lubricated mechanical systems. Hence, an operational baseline can easily be established by sampling every 50-500

9、hours of operation (approximately every one to three months, depending on system criticality), and used for quantitative trending analysis. Any anomalies in the wear particle concentration, especially in the generation rate of large particles (20 microns), is symptomatic of the onset of failure. For

10、 consistent results and accurate trending, lubricant samples are taken from the same places in the system each time. The method of sample extraction assures that the lubricant samples contain a representative selection of wear particles. The samples are then ferrographically analyzed both quantitati

11、vely and qualitatively.The Direct Reading Ferrograph (DRIII) classifies metallic wear particles as either large (20 microns) or small (20 microns) and calculates the large to small wear concentration. These values are entered into the personal computer based Ferrotrend database, which compiles the d

12、ata points for wear trending analysis. This process determines the existence of a malfunctioning component in the system.The Dual Ferrograph Analyzer prepares the ferrogram (slide) for analysis through the Ferroscope IV Microscope. The qualitative analysis is documented in the Ferrogram Analysis Rep

13、ort Sheet which documents the severity concentration of specific normal and abnormal wear particles.The ferromagnetic particles are sorted by gravity according to relative size, with larger particles appearing at the leading entry of the ferrogram. Non-magnetic particles (including contaminants and

14、friction polymers) are distributed throughout the ferrogram. This process indicates the presence of contaminants, the condition of the lubricant, and the material composition of the abnormal wear particles being generated, from which the source of the wear may be deduced.Ferrography is just one of t

15、he methods used at KSC. Ferrographic, viscosity, total acid number and vibration analysis are cooperative elements of the predictive maintenance program.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-refer to D descriptionProvided by IHSNot for Resa

16、leNo reproduction or networking permitted without license from IHS-,-,-D References:1. GSE Health Trend Analysis - RT-ENG-2/ 90-2182. P/PM Technology - March/April - 19913. Standard Oil Engineered Materials -Technical Bulletin 1014. Predictive Maintenance Engineering Lab, USA/KSC.Impact of Non-Pract

17、ice: Ferrography is a wear particle analysis utilizing diagnostic and predictive techniques to evaluate the on-line condition of interacting lubricated or fluid powered parts or components. The use of Ferrography to evaluate a systems condition is to avoid time-consuming and potentially damaging har

18、dware teardown and other destructive or interfering inspections. Ferrography can analyze a systems fluid to determine the type of wear it is experiencing; and, hence, predict the type of system failure and when the failure may occur. Ferrography can provide an established and easily performed inspec

19、tion method for determining the health of a system and providing an early failure detection method.Related Practices: N/AAdditional Info: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Approval Info: a71 Approval Date: 2000-04-20a71 Approval Name: Eric Raynora71 Approval Organization: QSa71 Approval Phone Number: 202-358-4738Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-