Six common misconceptions about equipment lubrication

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In enterprise equipment management, equipment lubrication is an unavoidable issue, yet many employees do not pay enough attention to it, which leads to various misunderstandings. This not only fails to benefit equipment management but also causes significant damage to the equipment. Experts point out that in daily work, many people have various misconceptions regarding equipment lubrication, or rather, they make empiricist mistakes. Myth 1 – Equipment lubrication means just adding oil. Lubrication is not that simple; it is a science that makes use of fundamental theories such as fluid mechanics, solid mechanics, materials science, applied mathematics, and physical chemistry to study lubrication principles, lubricant materials, and lubrication methods, with the aim of controlling harmful friction and wear. Adding oil is merely one aspect of lubrication. The lubrication of a device actually begins at its design stage and continues throughout the entire lifespan of the device. Myth 2 – The more oil, the better. This is not true. Simply put, lubricant is applied between two friction surfaces in order to create a thin layer of oil there, preventing direct contact and thus reducing wear. However, considering some side effects of adding lubricant, it is necessary to strictly control the amount of oil used. For example, in reducers, in order to reduce friction during gear movement and the rise in oil temperature, the depth of the gears submerged in the oil should be 1 to 2 tooth heights; less oil should be used at higher rotation speeds. Similarly, when lubricating the rolling bearings of the wet end rollers in the paper feed machine, care must be taken not to fill the bearing chambers completely, as this will increase resistance during rotation and lead to overheating; generally, filling 1/3 to 2/3 of the chamber is sufficient. Myth 3 – All lubricants can be used interchangeably. The choice of lubricant for equipment depends on the machine’s operating conditions, working environment, specific characteristics of the friction surfaces, as well as the lubrication method; as a result, the type and grade of lubricant used vary accordingly. For equipment with high rotational speeds and a strong capacity to create an oil wedge effect, lubricants with low viscosity should be used ； When the load per unit area on the friction surfaces of the equipment is high, lubricants with high viscosity and good oiliness should be used ； When the operating temperature of the equipment is high, lubricants with higher viscosity, higher flash point, better oiliness, and greater stability, or greases with a higher drip point, should be used ； The smaller the gap between the friction surfaces of the equipment, the lower the viscosity of the lubricating oil that should be chosen ； The rougher the friction surface, the higher the viscosity of the lubricant that should be chosen; if grease is used, the working taper should be smaller ； In pressure cycle lubrication, where the oil temperature is high, lubricants with higher viscosity should be used. The lubricants for different equipment are selected strictly in accordance with the aforementioned principles and experimental results. Under normal circumstances, they cannot be used as substitutes; any attempt to do so will disrupt the lubrication environment of the equipment, leading to wear and damage to the machinery and resulting in financial losses. Myth 4 – It’s okay to mix lubricants. Lubricants are petroleum products derived from oil and refined through various processes; different types and brands of lubricants contain different components in varying proportions. Generally speaking, lubricants should not be mixed together. To improve the physical and chemical properties of lubricating oil, a certain amount of additives must be added to it. The additives in various lubricants differ from one another; they include antioxidants, viscosity enhancers, oil-based additives, and extreme pressure additives. When lubricants of different types and grades are mixed together, chemical reactions may occur between the additives in the oil, resulting in the loss of their effectiveness and compromising the performance of the lubricant. Myth 5 – Changing oil frequently in equipment prevents major problems. Frequent oil changes are a waste and can also hide equipment faults. To determine whether lubricant loses its usability over time, it can be assessed from the following aspects. (1) Viscosity test. Typically, the lubricant already in use in the equipment and a lubricant of the standard viscosity required for that equipment are tested using a comparative method to determine whether oil change is necessary. (2) For testing for moisture, clean, dry cotton yarn is dipped into the oil to be tested and then set on fire; if there is water in the oil, an explosive sound and a flash will occur. (3) Inspection for mechanical impurities. Lubricants with low viscosity can be directly poured into a test tube, heated slightly, and then observed at rest. Oils with high viscosity can be diluted 5 to 10 times with clean gasoline, and the above method can be used to observe and determine whether oil replacement is necessary. (4) Identification of whether oxidation and deterioration have occurred. To determine whether the lubricant has suffered severe oxidation and degradation, take the sludge at the bottom of the oil tank and rub it between the index finger and thumb. If a high amount of gum-like substance is felt and strong adhesion is observed, it indicates that the lubricant in question has undergone severe oxidation and degradation. This method can be used to decide whether it is necessary to change the oil. (5) During equipment maintenance, the quality of grease is assessed by checking for any changes in its properties and the presence of impurities, which helps determine whether it is necessary to replace the grease. Myth 6 – Equipment lubrication necessarily implies leaks. Leaks in equipment refer to abnormal conditions where leaks are not allowed according to the technical specifications of the equipment, or when the amount of leakage exceeds the limits specified by those technical standards. Severe oil leakage not only causes oil shortages or outages, affecting the smooth progress of production, but also pollutes the surrounding environment. This not only undermines civilized production but also wastes lubricant. People use lubricants to lubricate equipment, but this introduces the problem of oil leakage. However, people are not at a loss when it comes to equipment oil leaks; there are many methods and ways to prevent them. As long as proper attention is given in terms of mindset and technical measures are put in place, it is possible to achieve both equipment lubrication and leak prevention.