In the industrial production process, equipment is both a vital vehicle for production and the material basis for the company's survival. The quality of equipment operation directly affects the company's production, operations and profits.
Therefore, lubrication and maintenance of the equipment are of crucial importance. Lubrication and maintenance are the foundation of equipment use and management and are essential methods for keeping equipment running smoothly and in good condition.
They are also an objective requirement for equipment operation. The ability of equipment to maintain long-term operation largely depends on the level of lubrication and maintenance.
Proper lubrication and maintenance can promptly detect and resolve many problems that may arise, create a conducive environment for equipment operation, and prevent problems before they occur.
Therefore, rational, scientific and effective lubrication maintenance management can ensure the normal operation of equipment, reduce equipment wear, lower maintenance costs and extend equipment life.
I. Meaning and role of mechanical equipment lubrication maintenance
1. Importance of Lubrication Maintenance of Mechanical Equipment
Equipment lubrication management is an essential method to ensure the normal operation of equipment, reducing wear on equipment parts, increasing production efficiency, improving equipment use efficiency, reducing equipment failure rates and decreasing equipment maintenance costs.
During the equipment operation and management process, it is based on the principle of “three-part treatment, seven-part maintenance”. Therefore, maintaining equipment lubrication is a crucial part of managing the complete equipment cycle.
It is necessary to do a good job of managing equipment lubrication, promptly inspect and deal with various problems with the equipment itself, eliminate unnecessary wear and tear on equipment, improve equipment operating conditions, and prevent problems before they occur.
Lubrication maintenance must be established based on scientific management. It has an extremely important meaning in ensuring normal production in companies, maintaining the good condition of equipment, demonstrating its efficiency, reducing equipment failures and increasing economic benefits.
2. Functions of Equipment Lubrication Maintenance
The functions of equipment lubrication maintenance include reducing friction, reducing wear, cooling and reducing temperature, cleaning and sealing.
(1) Reducing friction
Reducing frictional resistance to save energy, reduce wear, extend equipment operating cycle and improve economic efficiency.
(2) Reduced wear
The oil film formed between relatively moving friction pairs can reduce friction, reduce surface wear and scratches, and maintain the fitting accuracy of parts.
(3) Cooling and Temperature Reduction
The circulating lubrication system that uses liquid lubricants can remove the heat generated by friction.
(4) Corrosion prevention
The oil film formed between relatively movable friction pairs, when covered on the friction surface, can isolate air and corrosive gases and prevent the friction surface from being corroded or rusted.
(5) Transmission Force
Some lubricants can act as means of transmitting force, such as hydraulic oil.
(6) Shock absorption
Disperse load, alleviate impact and play a role in shock absorption and cushioning.
(7) Insulating
Mineral oils and other lubricants have high electrical resistance and can therefore serve as electrical insulating oils and transformer oils.
(8) Cleaning
With the circulation of lubricating oil, pollutants and debris on the friction surface can be transported and then filtered through a filter.
(9) Sealing
Lubricants form a seal on certain exposed parts, preventing the entry of condensed water, dust and other impurities and maintaining a sealed state between the cylinder and piston.
II. Selection of Lubricants for Mechanical Equipment
Lubricants are used to reduce frictional resistance between equipment parts and slow their wear. In mechanical equipment failures, 60% of equipment failures are caused by inadequate lubrication.
Therefore, lubricant selection is also of crucial importance and is the main link in lubrication management.
1. Classification of Lubricants
There are many types of lubricants and the classification varies according to different criteria. They are generally divided into four categories according to the state of the substance:
(1) Liquid Lubricants
In industrial and mining companies, the use and variety of liquid lubricants are greater, such as hydraulic oil, mechanical oil, etc.
(2) Semisolid lubricants (lubricating grease)
For example, lithium grease in soap-based grease has a wide range of uses and wide usage, and has excellent performance in many aspects.
(3) Solid Lubricants
The most commonly used solid lubricants are molybdenum disulfide, graphite and polytetrafluoroethylene.
(4) Gaseous Lubricants
Under certain conditions, the gas can also become a lubricant like a liquid.
2. Selection of Key Performance Indicators for Lubricants
Table 1: Selection of Main Lubricant Performance Indicators
| No. | Performance indicators | Meaning | Selection method |
| 1 | Viscosity | Viscosity is the internal resistance of a liquid when it flows, also known as internal oil friction. It is an indicator of the oiliness and fluidity of the oil. The higher the viscosity, the stronger the oil film, but the worse the fluidity. Viscosity is the most important performance indicator of lubricating oil and is the main basis for lubricating oil selection. | Determined by querying relevant graphs based on design or calculation data. |
| two | Pour point and cloud point | The pour point indirectly represents the low-temperature fluidity index of the lubricating oil during storage and use: the cloud point is approximately the highest temperature at which the oil loses its fluidity. | The usage temperature has been found to be 5-10°C higher than the pour point. |
| 3 | Flash point | The safety performance index of lubricating oil during storage and use. | Leave a safety factor of 1/2 according to safety regulations, which is 1/2 higher than the actual use temperature. |
3. Simple inspection methods for lubricants
Table 2: Simple Inspection Methods for Lubricants
| Project | Inspection method | Identification content |
| Appearance | Pour the oil sample into a clear glass container and observe the color for haze, turbidity, or dust | Air bubbles, moisture, dust, oil degradation |
| Smell | Compare with new oil, unpleasant or burning smell | Oil degradation |
| Acidity value | PH Test Strips | Oil degradation |
| Point method | Drop a drop of oil onto filter paper and let it act for 1 hour, observe the moistening situation | If the center of the oil-soaked spot appears as a thick, clear spot, this means wear dust, indicating that the oil has degraded. |
| Hot blast test | Drop oil onto a hot steel plate, check for a popping sound | Moisture |
| Fast viscosity detection | Use a simple viscometer | Viscosity |
4. Principles for Lubricant Selection
Generally speaking, the main indicator of lubricating oil is viscosity, while the main indicator of grease is its penetration rate.
(1) Principles for Lubricating Oil Selection
1) Workload
The workload of the movement pairs is directly related to the fluidity and anti-wear properties of the lubricating oil used.
Normally, when the workload is large, the viscosity of the lubricating oil used is higher, and its oiliness and resistance to extreme pressure must be excellent. When the workload is small, the viscosity of the oil used must be lower, with lower oiliness requirements and extreme resistance to pressure.
2) Speed
Normally, when the speed of the movement pair is high, a low viscosity lubricating oil must be used to reduce friction resistance, thus reducing the power consumed and the heat generated. For low speeds, a higher viscosity oil can be used.
3) Operating temperature
Operating temperature affects viscosity changes and the oxidation rate of the lubricating oil used. As the operating temperature increases, the viscosity of the lubricating oil decreases; conversely, viscosity increases.
Furthermore, under high temperatures, the rate of oxidation of the lubricating oil accelerates, causing its deterioration and shortening its useful life. Therefore, for lubrication points under high temperatures, lubricating oil with high viscosity, high viscosity index, high flash point and excellent resistance to oxidation must be used.
The flash point of general lubricating oil should be 20-30°C higher than the highest operating temperature. The high usage temperature for mineral lubricants is 120-150°C, for synthetic ester oils it is 200-250°C and for silicone oil it is 200-250°C.
4) Work Environment
For lubrication points that operate under humid conditions such as salt spray, water vapor, coolant or emulsion, oil and grease in general are prone to deterioration, emulsification or being washed away and lost.
In such cases, oily materials with strong anti-emulsification, rust resistance, corrosion resistance and strong adhesion should be chosen. Meanwhile, corresponding sealing measures must be adopted to prevent the intrusion of water and moisture, salt fog, etc.
In an average environment with chemical media, corrosive media (strong acids, strong alkalis, salts, etc.), the corrosion of oils and greases increases. Therefore, lubricants with good chemical stability must be chosen.
(2) Principles for Grease Selection
1) Workload
Choosing the grease based on the load is essential to ensure lubrication. For heavy load lubrication points, choose grease with high viscosity, high thickener content, high compressibility and high wear resistance.
For high loads, choose grease with low penetration (greater consistency). If subject to heavy, impact loads, choose grease containing pressure additives, such as grease containing molybdenum disulfide.
2) Speed
The higher the operating speed of the lubricated parts, the greater the shear stress in the grease, the greater the damage to the fibrous skeleton formed by the thickener and the shorter the useful life of the grease.
When temperature and load conditions are equal, speed is the main factor affecting grease application. Typically, high-speed parts heat up quickly and reach high temperatures, which can dilute the grease and cause it to be lost. In these cases, choose a grease with a higher consistency.
3) Operating temperature
Temperature significantly affects the lubrication function and service life of the grease. After the operating temperature of the lubrication point exceeds the upper limit of the grease temperature, for every 10-15°C increase in temperature, the useful life of the grease is reduced by approximately half.
This is due to accelerated loss by evaporation, oxidation and colloidal contraction of the base oil in the grease. Grease life decreases.
The operating temperature of the lubrication point also changes with the temperature of the surrounding medium. For high environmental temperatures and high operating temperatures of mechanical equipment, use high temperature resistant grease. The highest usage temperature of general grease should be 20-30°C lower than the dropping point.
4) Work Environment
Environmental conditions refer to the working environment and the environment surrounding the lubrication point, such as air humidity, dust and whether there are corrosive media. In humid environments and situations where there is contact with water, choose water-resistant grease such as calcium-based, lithium-based, or calcium-complex grease.
Under adverse conditions, choose grease with rust inhibitors and avoid choosing sodium-based grease with low water resistance. For lubrication points in environments with strong chemical media, choose synthetic grease resistant to chemical media, such as fluorocarbon grease, etc.
other considerations
In addition to the points above, when selecting lubricants, also consider the cost-benefit during use and analyze whether the use of this type of lubricant will prolong the lubrication cycle, increase the number of injections, grease consumption, the failure rate of the bearings and maintenance costs. , etc.
In addition to the points above, when selecting lubricants, also consider the cost-benefit during use and analyze whether the use of this type of lubricant will prolong the lubrication cycle, increase the number of injections, grease consumption, the failure rate of the bearings and maintenance costs. , etc.
III. Strengthening Lubrication and Maintenance Management of Mechanical Equipment
Paying close attention to managing the lubrication and maintenance of mechanical equipment is essential. Using human initiative can improve the effectiveness of equipment maintenance.
The core of equipment operation management is the transition from reactive to proactive approaches and from experience-based approaches to standardized approaches.
“Standardization” is the focus of equipment operation management, and lubrication and maintenance standards are key to equipment operation. Therefore, strengthening lubrication and maintenance management is crucial to extending the useful life of equipment.
1) Establish a comprehensive equipment lubrication management system
Many companies do not have a comprehensive system for managing equipment lubrication. They do not strictly follow the “Five Determinants” of mechanical equipment lubrication (location, timing, quality, quantity and personnel) and three-stage filtration management.
Enterprises must establish corresponding organizational structures, improve lubrication management regulations, perfect lubrication management details and implement them strictly.
2) Develop a lubrication maintenance plan based on actual equipment operation
During equipment operation, maintenance personnel often only add oil when the equipment level is low without a proper oil change plan. They lack basic methods of monitoring the oil and controlling contamination, relying only on experience to assess the quality of the oil.
Long-term operation can lead to oil contamination and degradation, accelerating equipment wear. It is crucial to develop adequate lubrication maintenance plans and lubrication chart cards detailing the oil change process to guide maintenance personnel in improving lubrication problems.
3) Enhance lubrication knowledge training and select lubricants reasonably
Companies should strengthen technical training in lubrication maintenance management, with personnel dedicated to management. From lubricant selection to application and recycling, it is essential to be scientific and reasonable.
At the same time, efforts should be made to learn and promote new products and technologies, effectively extending the useful life of the equipment.
4) Implement oil analysis on key equipment
Periodic oil analysis should be performed on major equipment and those requiring quality-based oil changes to understand the wear state of equipment lubrication and achieve predictive maintenance.
5) Control the oil filling quantity reasonably
In conclusion, the management of lubrication and maintenance of mechanical equipment is a critical aspect for the survival and development of a company. The quality of equipment directly impacts the company’s economic benefits.
When managing the entire life cycle of equipment, it is not just about managing the technical condition of equipment and diagnosing faults, but also about managing the economic benefits of operating equipment and energy resources.
Therefore, to extend the service life of equipment, management must prioritize the management of lubrication and maintenance during the operation process, manage lubrication scientifically and reasonably based on the actual operating conditions of the equipment, ensure reliable and stable operation of equipment, thus reducing the company's costs and increasing competitiveness.
