Performing grease analysis on a routine or as-needed basis provides useful information about the condition of the grease and bearing, while gauging the effectiveness of your maintenance strategy.
Grease is the preferred choice of lubricant for a variety of situations including:
- low-speed, back and forth, or minimal bearing rotation (i.e. oil circulation doesn’t work very well)
- high risk of shock loading / bearing deflection
- Concerns with sealing or leakage control
- Concerns with oil incompatibility or mixtures (i.e. zinc-based oils in an electric motor bearing)
- Serviceability concerns (i.e. restricted access, remote access)
These issues are carefully considered during design of the system and are just as important during operation. These conditions are often the exact failure modes that need to be monitored and controlled.
Common Grease Applications
The following are common applications for grease lubrication:
- Ball, Roller, Plain Bearings
- Electric Motor Bearings
- Large Caster Bearings / Slew Rings
- Wind Turbine Bearings: Main, Yaw, Generator, Pitch Adjustment
- Couplings / Linkages
- Robotic Arms
- Automatic Lubrication Systems
Grease Testing Options & Resources
Screening Test Package
Routine Tests: Color, Total Magnetic Iron (TMI), FTIR Identification
Sampling Frequency: As needed
- Small Electric Motors
- Chain Grease
- Mobile Joints
- Wheel Bearings
Standard Test Package
Routine Tests: Color, Total Magnetic Iron (TMI), FTIR Identification, Penetration Test (unworked), ICP Spectrometry
Sampling Frequency: 2x per year or as needed
- Large Electric Motors
- Automatic Greasing Systems
- Robot Arms
Advanced Test Package
Routine Tests: Color, Total Magnetic Iron (TMI), FTIR Identification, Penetration Test (unworked), ICP Spectrometry, RULER (Remaining Useful Life) of Grease, Analytical Ferrography
Sampling Frequency: 2x per year or as needed
- Large Diameter Bearings
- Rolling Element
- Troubleshooting Bearing Failures*
- Condition-based Grease Program*
- Confirmation Of
- Grease Quality*
- Grease Stability*
- Grease Compatibility*
*May require additional, triggered, or custom tests. Contact Fluid Life for more information.
When deciding to make a lubricant change, grease compatibility must be taken into consideration. Whether two greases are compatible depends on:
- Thickener type
- Base fluid
- Resulting grease properties after mixing
While the compatibility chart provides a general guideline to determining the basic compatibility between two greases, a grease compatibility test is recommended when critical applications are involved.
As with any lubricant, we recommend that you consult the equipment service manual or contact your machinery manufacturer to see what they recommend when determining what grease to use in your specific application. The safest practice is to avoid mixing of greases.
Fluid Life can also conduct grease compatibility tests – contact us to find out more.
(Preferred for In-Service Grease)
- Open bearing cap (preferred) or grease nipple
- Insert syringe + extender tube
- Pull plunger to extract grease into the extender tube
(Purged Grease / Disassembled Bearings)
- Identify the used grease to collect
- Used grease darker than new grease
- Outer layer of purged grease may not be representative
- Scrape used grease from the desired location
- Cage bars / raceways / roller set
- Collect the grease in a baggy or container
- Repeat process until you have enough grease for testing
The following list of best practices will help to improve the overall quality of your grease lubrication program:
- Dedicate a grease gun to a grease type and tag it using a unique color or shape coding and clear lettering.
- Avoid mixing greases with incompatible base oils, additives, and thickeners – always consider grease compatibility when changing grease.
- Regularly calibrate your grease application guns in case the gun’s output per shot changes.
- Keep guns clean and avoid laying them on dirty surfaces. Repack on a clean bench using a gun loader fitting. Keep covered when not in use.
For additional best practices, read our 6-Step Guide to an Improved Greasing Procedure.
Take the next step
Depend on over 30 years of experience in fluid testing and analysis to improve your predictive maintenance programs and reduce unplanned downtime.
Contact Fluid Life to develop and implement a grease analysis program that fits your needs.
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