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Total cleanliness control (TCC) is defined as a comprehensive wear control strategy for reducing hydraulic and lubricating system operational and maintenance costs in the primary metals industry. TCC establishes fluid cleanliness standards and defines how to apply and specify filtration technology to achieve these cleanliness targets while using oil analysis to monitor results. TCC also requires the filter vendor to provide a full range of application, technical, and scientific support services to maximize cost savings and productivity gains obtained through improved hydraulic and lube oil cleanliness.
Key Words
Cleanliness, Hydraulic System Components
Introduction
Oil contamination poses a serious threat to the performance and reliability of hydraulic and lube systems in the primary metals industry. This paper examines the nature of mechanical wear caused by particulate contaminants in hydraulic and lubricating fluids and introduces the concept of total cleanliness control (TCC) as a means for controlling it. Mills that aggressively implement TCC wear control programs can achieve a competitive advantage over those who choose to ignore the effects of mechanical wear. A relatively small investment in TCC training and technology can reap dividends of thousands of dollars in reduced replacement component costs, maintenance labor savings, and reduced equipment downtime.
Sources of Contaminants
There are four primary sources of particulate contaminants in mill hydraulic and lubricating systems. Built-in contaminants come from components, fluids, hoses, reservoirs, etc. Generated contaminants result from the assembly of a system, break-in of a system, operation of a system, and fluid breakdown.
Externally ingressed contaminants enter a system through reservoir breathing, cylinder rod seals and bearing seals, while maintenance-related contaminants are introduced when equipment is disassembled/assembled and makeup oil is added.
Effective on-board filtration and conscientious maintenance practices will slow the ingression of contaminants from built-in, generated and maintenance-related sources. External ingression, however, is often far more difficult to control in a mill environment. Consider, for example, the tremendous amounts of metallic fines and roll coolant which continuously flow into a Morgoil lube system through roll neck bearing seals.
Mill engineers must consider such uncontrollable ingression points to establish fluid cleanliness goals that are both realistic and costeffective to reach.
Factors that Cause Equipment Failures
A study by Dr. E. Rabinowicz at M.I.T. investigated the reasons for component replacements or "loss of...