ICML CERTIFICATION SERIES
Fig. 2. A simple depiction of 2- and 3-body abrasive wear (Source: ENGTECH Industries)
The Stribeck Curve clearly demonstrates that a hydrodynamic film regime—of the correct viscosity and Lambda thickness—results in the lowest coefficient of friction and least wear. Common wear mechanisms There are four common wear mechanisms that cause surface degradation and eventual loss of usefulness in bearing surfaces. 1. Abrasive wear occurs when bearing surfaces run in a MF or BL regime. Abrasive wear can occur as a result of a 2-body or 3-body surface interaction. In the 2-body example shown in Fig. 2, we see two surface points that touch and cut into the opposing sliding surface, resulting in a scratched, grooved or furrowed surface and a thirdbody metal cutting being released into the lubricant.
As reflected in the 3-body diagram, that third body is now free to get caught between two surface points and add to the surface degradation. A 3-body abrasion can also occur due to large particles (dirt) in the lubricant (introduced by the lubrication process or machine operation). Erosive wear is a form of abrasive wear caused by particles impacting a surface. 2. Adhesive wear typically occurs under highly loaded sliding friction, when an incorrect viscosity lubricant is used, EP and AW additives have been depleted or under heavy shock loading. As the surfaces come together, they weld under the heat and load pressure, and metal is transferred and torn apart under movement, leaving discreet, often jagged or smeared, surfaces. Adhesive wear is also described as scuffing, shearing or galling wear.
Update On Lubrication Certification Opportunities Today, there are two main certifying programs for lubrication professionals: STLE (Society of Tribologists and Lubrication Engineers); and ICML (International Council for Machinery Lubrication). Originally designed for engineers, STLE's Certified Lubrication Specialist (CLS) program has been offered since 1993. ICML’s certification program was the basis for and is in accordance with ISO’s 18436 standard series, as it relates to lubricantbased condition monitoring professionals. ICML offers two certification paths for “hands-on” lubrication practitioners: MLT (Machine Lubrication Technician) and MLA (Machine Lubrication Analyst) designations. ICML also separates field functions from laboratory functions, with lab practitioners served by the LLA (Laboratory Lubricant Analyst) designation. ICML programs have been offered since 2001. In 2008, its MLT and MLA certifications were pioneered into
ISO 18436-4 for field practitioners. In 2012, its LLA certification became the basis of ISO 18436-5, for lab-based practitioners. Participants who attend the requisite formal preparatory training associated with ICML certification are also eligible to take exams as per the corresponding ISO standard (upon payment of the appropriate examination fee). Of these all these programs, ICML’s (currently offered in 10 languages) has issued the most certificates around the world (over 9500 to date, with presence in more than 95 countries). One of the most recent ICML certification preparatory-training and exam opportunities in the U.S. was offered at the 2013 Maintenance & Reliability Technology Summit (MARTS) conference, in Chicago (Rosemont), IL. For more information on ICML certification, please visit: www.lubecouncil.org.
EDITOR’S NOTE: This information is a corrected version of previous sidebars on certification opportunities that ran in the January/February and March/April issues of LMT. 22 | LUBRICATION MANAGEMENT & TECHNOLOGY
MAY/JUNE 2013