Grease particle counting ASTM 2015
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The document discusses advancements in particle counting methods for greases, emphasizing the importance of monitoring particulate contamination in lubrication systems. It critiques current testing methods as labor-intensive and subjective while introducing a new ASTM D7718-based approach that reliably sizes and counts grease particles down to 10 microns. Additionally, it outlines potential sources of error and future work for improving particle counting in various grease formulations.
Grease particle counting ASTM 2015
- 1. 1© 2015 MRG Laboratories. All rights reserved. Automatic Particle Sizing and Counting in Greases Rich Wurzbach MRG Labs York, Pennsylvania, USA
- 2. 2© 2015 MRG Laboratories. All rights reserved. Background • Particle counting is very important part of oil analysis programs. • Filtration and online contamination monitoring are used to maintain lubricant cleanliness. • No commercial-scale contamination tests for grease as exists for oil, such as laser scattering particle counting. • Abrasive contamination can be just as destructive in grease applications. • Monitoring can allow for intervention through improved handling and manufacturing practices, grease flushing, and changes to relubrication frequency, volume.
- 3. 3© 2015 MRG Laboratories. All rights reserved. Current Methods • Direct – Analytical Ferrography – Labor intensive, difficult preparation – Federal Standard 791D, Method 3005.4, Dirt Content of Grease, microscopic evaluation – DIN 51813, Solid Matter Content of Lubricating Greases • Indirect – Elemental Spectroscopy – Elemental concentration don’t tell the whole story – P-Q testing with Hall Effect sensor – Only Ferrous debris – Hegman Gage – Semi-quantitiative based on size – ASTM D1404 "Deleterious Particles" - effect of particles on scratching plates
- 4. 4© 2015 MRG Laboratories. All rights reserved. Current Methods • DIN 51813, Solid Matter Content of Lubricating Greases • Federal Standard 791D, Method 3005.4 • Hegman Gage, ASTM D1210Source: “Deleterious Particles in Lubricating Greases”, C. Coe, STLE Online
- 5. 5© 2015 MRG Laboratories. All rights reserved. Current Methods • Analytical Ferrography • ASTM D1404, Estimation of Deleterious Particles in Lubricating Grease
- 6. 6© 2015 MRG Laboratories. All rights reserved. Limitations of current methods • Subjective interpretation of results • Selection of solvent critical to some tests, may be more difficult when evaluating inservice lubricants to get complete dissolution • Time consuming and some expertise may be required • None would be considered production lab ready
- 7. 7© 2015 MRG Laboratories. All rights reserved. New Method: Particle Counting • New method uses ASTM D7718 sampling standard capture device for presentation of 1 gram representative sample • Samples can be obtained from: – new grease in manufacturing process – packaged new greases upon opening – stored greases in opened packages – grease guns and auto-lubers – inservice samples in the machine • Method sizes and counts particles reliably down to 10 micron in major axis, and provides aspect ratio and other characterization information
- 8. 8© 2015 MRG Laboratories. All rights reserved. Grease Sampling ToolsGrease Sampling Tools
- 9. 9© 2015 MRG Laboratories. All rights reserved. Grease Thief Analyzer for Die Extrusion
- 10. 10© 2015 MRG Laboratories. All rights reserved. Analysis Techniques Sample is received. fdM+ is run Die extrusion is performed and substrate is made Two strips are used to make a dilution to run RDE/ICP. One Strip is used for FT-IR. One Strip is Dissolved in Green RULER solution to run RULER.
- 11. 11© 2015 MRG Laboratories. All rights reserved. Die Extrusion prior to Particle Counting
- 12. 12© 2015 MRG Laboratories. All rights reserved. Oil Particle Counter Principle Adapted • WK29409 Standard Test Method for Automatic Particle Counting and Particle Shape Classification of Oils Using a Direct Imaging Integrated Tester (D02.96.7) • Use of camera and particle identification and sizing software originally used for flow-through oil particle characterization • Modification of platform and use of alternate lighting methods
- 13. 13© 2015 MRG Laboratories. All rights reserved. Camera Set-up • Thin Film extrusion sample preparation • Lens magnification to achieve 10 micron particle resolution • Backlit with synchronized high-intensity LED lighting
- 14. 14© 2015 MRG Laboratories. All rights reserved. Modification of Grease Thief Analyzer
- 15. 15© 2015 MRG Laboratories. All rights reserved. Challenges • Strobing backlight solved 2 problems – Testing with frontlight set-ups were unsuccessful due to the glare produced by the grease surface – Samples were too dark and the film was too thick to employ a traditional backlight – improvement achieved with synchronized LED. • Thin film preparation – Provides a consistent gap thickness – Allows for volumetric calculations
- 16. 16© 2015 MRG Laboratories. All rights reserved. Particle Mask
- 17. 17© 2015 MRG Laboratories. All rights reserved. Case Study • Chiller Motor ODE Bearing sample • Relatively low wear levels • Slightly elevated concentrations of elements the could be environmental contamination • Also showed signs of grease product mixing • Elemental Spectroscopy doesn’t show the whole picture Fe Al Si Mg Zn FdM 3.1 2.4 9.5 34 645 99
- 18. 18© 2015 MRG Laboratories. All rights reserved. Particle Counting Sample Image Image with filter and particles highlighted
- 19. 19© 2015 MRG Laboratories. All rights reserved. Particle Counting - Results Particle Count: 327 Mean Area: 1564.2 Mean Major Axis: 45.0 Min Major Axis: 14.6 Max Major Axis: 184.2
- 20. 20© 2015 MRG Laboratories. All rights reserved. Particle Counting - Results
- 21. 21© 2015 MRG Laboratories. All rights reserved. Backlight arrangement
- 22. 22© 2015 MRG Laboratories. All rights reserved. Die Extrusion of Hegman samples • Samples A, B, E, and H could be processed without dilution • Other samples have excessive attenuation of light signal at current thickness and content
- 23. 23© 2015 MRG Laboratories. All rights reserved. Samples sent out in June 2014-Kaperick GR-193-A PTFE containing GR-193-B Lithium complex GR-193-C Li-Cx w/MoS2 & polyethylene GR-193-D Li-12 w/MoS2 & graphite GR-193-E Lithium complex GR-193-F Lithium w/white solids (ZnO, TiO2) GR-193-G Polyurea GR-193-H Calcium Sulfonate Permis sion L (mm) W (mm) D (mm) Volume (mm^3) Lab A Afton Chemical Yes 165.1 25.4 0.100 419 Lab B ExxonMobil Yes 155.58 50.8 0.100 790 Lab C University of Akron Yes 127.5 33 0.100 161 Lab D Axel Christiernsson Yes 127.5 33 0.250 1052 Lab E SKF Yes 127 50.8 0.050 323 Lab F Chemtura Yes 165 11 0.100 182 Lab G Summit Yes 165.1 25.4 0.100 419
- 24. 24© 2015 MRG Laboratories. All rights reserved. Proposed ratings-Kaperick/Afton PTFE containing Lithium complex Li-Cx w/MoS2 & polyethylene Li-12 w/MoS2 & graphite GR-193-A GR-193-B GR-193-C GR-193-D Lab A Lab B Lab C Lab D Lab E Lab F Lab G Lab A Lab B Lab C Lab D Lab E Lab F Lab G Lab A Lab B Lab C Lab D Lab E Lab F Lab G Lab A Lab B Lab C Lab D Lab E Lab F Lab G <26 C C A C A C A A A A A A B C C C C C B B A C A C 26-80 B C A B A C A A A B A A B C A B C C A B A A B C >80 A B A A C A A A A A A B A B C A A A A C D1404 3 3 1 3 1 1 1 1 1 1 1 3 3 2 1 2 24 Lithium complex Lithium w/white solids (ZnO, TiO2) Polyurea Calcium Sulfonate GR-193-E GR-193-F GR-193-G GR-193-H Lab A Lab B Lab C Lab D Lab E Lab F Lab G Lab A Lab B Lab C Lab D Lab E Lab F Lab G Lab A Lab B Lab C Lab D Lab E Lab F Lab G Lab A Lab B Lab C Lab D Lab E Lab F Lab G <26 A A A C A A B B A C A C A C A C C C A C C C C C 26-80 A A A A A A A B A A A A B A A B C C B A B B C C >80 A A A A A A A A A A A A A A A A A A A A D1404 1 1 1 2 1 1 1 2 2 3 1 2 3 2 1 3 L (mm) W (mm) D (mm) Volume (mm^3) Lab A Afton Chemical 165.1 25.4 0.100 419 Lab B ExxonMobil 155.58 50.8 0.100 790 Lab C University of Akron ` 127.5 33 0.100 161 Lab D Axel Christiernsson 127.5 33 0.250 1052 Lab E SKF 127 50.8 0.050 323 Lab F Chemtura 165 11 0.100 182 Lab G Summit 165.1 25.4 0.100 419
- 25. 25© 2015 MRG Laboratories. All rights reserved. Sample A
- 26. 26© 2015 MRG Laboratories. All rights reserved. Sample A Thresholding
- 27. 27© 2015 MRG Laboratories. All rights reserved. Particle Sizing – Grease A PTFE containing Lithium complex Li-Cx w/MoS2 & polyethylene Li-12 w/MoS2 & graphite GR-193-A GR-193-B GR-193-C GR-193-D Lab A Lab B Lab C Lab D Lab E Lab F Lab G Lab A Lab B Lab C Lab D Lab E Lab F Lab G Lab A Lab B Lab C Lab D Lab E Lab F Lab G Lab A Lab B Lab C Lab D Lab E Lab F Lab G <26 C C A C A C A A A A A A B C C C C C B B A C A C 26-80 B C A B A C A A A B A A B C A B C C A B A A B C >80 A B A A C A A A A A A B A B C A A A A C D1404 3 3 1 3 1 1 1 1 1 1 1 3 3 2 1 2 Table: Grease A Size (microns) Sieve # Vol% Population% Population -------------------------------------------------------------------------------------------------------------------------------- ---------- 0 - 10 pan 0 0 0 10-25 Custom 2.4 31.681362 3126 25 - 75 Custom 41.3 63.190433 6235 75 - inf 200 USS 56.1 5.128205 506
- 28. 28© 2015 MRG Laboratories. All rights reserved. Sample B
- 29. 29© 2015 MRG Laboratories. All rights reserved. Sample B Thresholding
- 30. 30© 2015 MRG Laboratories. All rights reserved. Particle Sizing – Grease B PTFE containing Lithium complex Li-Cx w/MoS2 & polyethylene Li-12 w/MoS2 & graphite GR-193-A GR-193-B GR-193-C GR-193-D Lab A Lab B Lab C Lab D Lab E Lab F Lab G Lab A Lab B Lab C Lab D Lab E Lab F Lab G Lab A Lab B Lab C Lab D Lab E Lab F Lab G Lab A Lab B Lab C Lab D Lab E Lab F Lab G <26 C C A C A C A A A A A A B C C C C C B B A C A C 26-80 B C A B A C A A A B A A B C A B C C A B A A B C >80 A B A A C A A A A A A B A B C A A A A C D1404 3 3 1 3 1 1 1 1 1 1 1 3 3 2 1 2 Table: Grease B Size (microns) Sieve # Vol% Population% Population -------------------------------------------------------------------------------------------------------------------------------- ---------- 0 - 10 pan 0 0 0 10-25 Custom 0.12127 2 40.289855 1251 25 - 75 Custom 1.16758 6 45.120773 1401 75 - inf 200 USS 98.7111 4 14.589372 453
- 31. 31© 2015 MRG Laboratories. All rights reserved. Sample E
- 32. 32© 2015 MRG Laboratories. All rights reserved. Sample E Thresholding
- 33. 33© 2015 MRG Laboratories. All rights reserved. Particle Sizing – Grease E Lithium complex Lithium w/white solids (ZnO, TiO2) Polyurea Calcium Sulfonate GR-193-E GR-193-F GR-193-G GR-193-H Lab A Lab B Lab C Lab D Lab E Lab F Lab G Lab A Lab B Lab C Lab D Lab E Lab F Lab G Lab A Lab B Lab C Lab D Lab E Lab F Lab G Lab A Lab B Lab C Lab D Lab E Lab F Lab G <26 A A A C A A B B A C A C A C A C C C A C C C C C 26-80 A A A A A A A B A A A A B A A B C C B A B B C C >80 A A A A A A A A A A A A A A A A A A A A D1404 1 1 1 2 1 1 1 2 2 3 1 2 3 2 1 3 Table: Grease E Size (microns) Sieve # Vol% Population% Population ------------------------------------------------------------------------------------------------------------------------------- ----------- 0 - 10 pan 0 0 0 10-25 Custom 0.05 33.3 356 25 - 75 Custom 0.69 39.1 418 75 - inf 200 USS 99.2 27.4 293
- 34. 34© 2015 MRG Laboratories. All rights reserved. Sample H
- 35. 35© 2015 MRG Laboratories. All rights reserved. Sample H Thresholding
- 36. 36© 2015 MRG Laboratories. All rights reserved. Particle Sizing – Grease H Table: Grease H Size (microns) Sieve # Vol% Population % Population ------------------------------------------------------------------------------------------------------------------------------ ------------ 0 - 10 pan 0 0 0 10-25 Custom 1.9 56.9 5044 25 - 75 Custom 7.2 41.9 3711 75 - inf 200 USS 90.8 1.1 98 Lithium complex Lithium w/white solids (ZnO, TiO2) Polyurea Calcium Sulfonate GR-193-E GR-193-F GR-193-G GR-193-H Lab A Lab B Lab C Lab D Lab E Lab F Lab G Lab A Lab B Lab C Lab D Lab E Lab F Lab G Lab A Lab B Lab C Lab D Lab E Lab F Lab G Lab A Lab B Lab C Lab D Lab E Lab F Lab G <26 A A A C A A B B A C A C A C A C C C A C C C C C 26-80 A A A A A A A B A A A A B A A B C C B A B B C C >80 A A A A A A A A A A A A A A A A A A A A D1404 1 1 1 2 1 1 1 2 2 3 1 2 3 2 1 3
- 37. 37© 2015 MRG Laboratories. All rights reserved. Sources of Error • Spurious dirt on substrate – Maintain cleanliness of substrates, as in Analytical Ferrography • Optical artifacts such as bubbles, grease thickness variations – Algorithm to eliminate non-particle features • Highly attenuating matrix – Only applicable presently to high-transmittance samples • Some greases with distributed solid lubricants – Moly, graphite, ZnO, TiO2 greases not good candidates with current method due to attenuation
- 38. 38© 2015 MRG Laboratories. All rights reserved. Future Work-Particle Counting 1. Screening D7718 Grease Thieves for opacity and dilution prior to D7918 Die Extrusion 2. Evaluation of clear Extrusion Die for thin grease stream 3. Integration of technology to take video during extrusion for count averaging across a video instead of an image 4. Automation of the data collection process 5. Particle identification and characterization – Differentiating severe wear modes from normal rubbing wear 1. Establishing target limits and evaluation criteria for different applications
Editor's Notes
- #11: fdM+ ferrous debris analyzer Determines the amount of ferrous debris in a sample Grease Thief Analyzer Measures the consistency of the grease FT-IR Tests for mixing, contamination, and oxidation RULER Tests for amount of useful antioxidant life remaining RDE Spectroscopy metals spectroscopy Rheometer Tests the consistency, pumpability, and likeliness of tunneling