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leading to increased wear, higher temperatures, and decreased equipment longevity.
Tests and Case Study – Effectiveness of copper filming technology A comprehensive case study was conducted in the mining industry to validate the effectiveness of copper filming technology. Mining is an ideal test case as it is known for its demanding operating conditions. The test focused on a ball mill with a useful load of 500 tons, equipped with a centralised lubrication system and utilising a standard EP, NLGI 0 open gear grease manufactured by a major European brand. Gear width was 1050 mm, and the module of the tooth was 45 (ratio of reference diameter to number of teeth). Throughout the gearbox’s operation, temperature was recorded via three sensors positioned at the ends and middle of the gear face.
A standard lithium grease of EP0/00 grade with a synthetic base (viscosity of 220 cSt at 40 °C) and a fully oil-soluble CFT additive package was used for the test.
Before the start of the test, the mill had been in operation for over 40,000 hours, displaying a slight misalignment between gears. Temperature readings highlighted significant differences. The temperature
readings were as follows: 42.1 °C; 54.5 °C; 63.2 °C, with a delta of 21.0 °C across the face.
After replacing the standard grease with a one with CFT in it, an initial temperature increase was observed. It has been determined that this was associated with the removal of the molybdenum disulfide (MoS2
) solid
lubricant film formed by the incumbent product. The maximum temperature regime recorded after 5 hours of operation with CFT grease was: 42.8 °C; 55.8 °C; 64.7 °C, with maximum delta reaching 26.0 °C in the first 24 hours.
Based on previous experience with CFT greases, it is understood that around this time the MoS2
layer was
completely removed, and the CFT additive begins to work. At this point the processes of hydrogen smoothing in the friction zone and the formation of a protective copper coating begins.
After one and a half months of running on the new grease (over 1000 hours), the temperature regime recorded a remarkable improvement. The temperature regime recorded on CFT was 38.0 °C; 40.6 °C; 44.3 °C with a delta of 6.2 °C.
CFT significantly improved reliability of the ball mill, reducing temperatures at respective points and
Figure 1: Temperatures across the gear face. 22 LUBE MAGAZINE NO.180 APRIL 2024
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