Formulating grease is often referred to as an art, but what sometimes gets overlooked is the work behind the art. A successful formulation requires tremendous resources, expertise and grease of the elbow variety. Like a successful artist, the grease formulator needs to have the proper tools of the trade: a broad palette of additive chemistry, a well-lit (and ventilated) studio and a wide range of tools to create and evaluate potential masterpieces. As many professional artists will attest, the creative process is a painstaking route that can involve a huge amount of effort to create a single finished piece and the toolkit can be a critical factor in both the timing and quality of the final product. Afton’s Grease Team has assembled an exceptional array of instruments and techniques to help drive innovative development and to increase the formulator’s understanding of the science behind the art.

A newer accessory for the rheometer is the Anton Paar Bearing Attachment, see Figure 4, which allows testing of grease characteristics in actual bearings of interest. It can be operated under the same conditions as the Tribology Cell to generate friction data at various loads, speeds and temperatures which can be more directly applied to predict field performance of specific grease formulations.


Figure 4. Rheometer with Bearing Attachment.

Rig tests
The workhorses of the grease industry are rig tests designed to measure extreme pressure, friction and wear properties under various conditions. Afton’s rigs are kept busy evaluating various customer grease formulations and new component research.

• Timken Extreme Pressure Tester fitted with a Falex grease delivery device allows determination of Timken OK load values using ASTM D 2509.
• The Four Ball Wear tester measures the average wear scar worn into the fixed balls by rotating one ball against them under various conditions as outlined in ASTM D 2266.
• The Four Ball Weld tester rotates one ball against three fixed balls for 10 second intervals at each load level under standard conditions as described in ASTM D 2596.
• The Fafnir Fretting Wear test rig employs two ball thrust bearings oscillated under standard test conditions with the fretting wear reported according ASTM D 4170.
• An Optimol SRV, see Figure 5, uses a ball-on-disk method to measure both the wear scar generated on the test disk and the coefficient of friction during the test run. A wide variety of loads, temperatures, stroke lengths and frequencies can be used to study performance aspects of grease formulations including but not limited to those outlined in ASTM standards D 5707 (friction and wear) and D 5706 (extreme pressure).
• Forschungsstelle fur Zahnrader und Getriebebau (FZG) rig assesses the relative load-carrying capacity of greases and oils used to lubricate steel gears; can be used for wear testing especially for open gear applications.


Figure 5. Optimol SRV tester.

Physical characterization
A state-of-the-art analytical lab is the Swiss Army knife in any formulator’s toolbox and Afton’s lab is no exception. From elemental analysis (including digestion techniques for those hard to dissolve grease samples) to spectroscopic techniques (NMR, FTIR) to chromatography (HPLC and GC, with or without mass spec, and a host of other detectors) to oxidation and thermal testing (PDSC, TGA) to a broad range of physical characterization methods, this tool is indispensable to the grease formulator.

As for the “well-lit (and ventilated)” workspace, Afton’s recent 30,000 square foot expansion includes a brand-new grease “studio” with plenty of bench space for modeling new formulations. The $10 MM expansion allows plenty of room to spread out the expanding industrial business testing needs. This new lab now contains a wide variety of blending and testing equipment to support Afton’s grease customers including:

• Hobart mixers for blending up to 10 gallons finished grease formulation
• Speedmixer for quickly blending and deaerating up to 500 g grease formulations; allows easy blending of design matrices for performance evaluation
• Standard grease equipment for measuring penetration, dropping point, copper corrosion
• EMCOR dynamic corrosion test rigs as well as standard bearing corrosion tests (and humidity cabinet, as needed)
• Shell Roll Stability for testing stability of greases under low shear conditions at a range of temperatures with or without the presence of water
• Various test rigs to measure separation of oil from grease at test temperatures
• Hegman gauge and D 1404 apparatus to measure grease cleanliness
• Lab-scale grease pilot plant allows production of specific grease thickener formulations, as well as evaluation of polymer and additive effects on finished greases

This array of tools complements our line of innovative componentry that is essential in supporting the creative process of developing successful grease formulations. This line includes components offering AW/EP, rust and corrosion protection, friction modification, thickening, as well as additive packages serving needs from core building blocks to customized applications.