Determination of equipment maintenance mode
Equipment maintenance can be divided into planned preventive maintenance, which should be emphasized from the perspective of ensuring the safe operation of equipment. Planned maintenance is to formulate the maintenance and repair methods of equipment according to the law of equipment wear and failure. According to different maintenance functions, maintenance methods can be divided into maintenance, targeted maintenance, planned maintenance, project maintenance and renovation maintenance. The selection and determination of maintenance methods are mainly based on the degree of wear, performance, accuracy degradation and the possibility of failure of equipment and its components.
1. Three Difficult Maintenance Systems
Equipment maintenance is divided into daily maintenance, primary maintenance and secondary maintenance according to workload and difficulty, and the resulting maintenance system is called "three-level maintenance system".
(1) Daily maintenance
It is the equipment maintenance work that operators must carry out in each shift, including cleaning, oiling, adjusting, replacing individual parts, checking lubrication, abnormal noise, safety and damage. Daily maintenance is combined with daily spot check, which is a kind of equipment maintenance method that does not occupy man-hours alone. (2) Primary maintenance
It is an indirect preventive maintenance form which is mainly based on regular inspection and supplemented by maintenance. Its main work contents are: check, clean and adjust the parts of each equipment; Check the impeller and seal of sewage pump and impeller, seal and oil filling of centrifugal pump; Check the wiring, dust removal and fastening of the power distribution cabinet; If hidden dangers and anomalies are found, they should be eliminated and leakage should be eliminated. After primary maintenance, the equipment shall be clean and bright; No dust; Flexible operation and normal operation; Safety protection and indicating instruments are complete and reliable. Maintenance personnel should record the main contents of maintenance, hidden dangers, anomalies, trial operation results, operation performance and other existing problems found and eliminated during maintenance. The first-level maintenance is mainly based on operators, and professional maintenance personnel cooperate with the guidance.
(3) Secondary maintenance
It is a form of maintenance to maintain the technical condition of equipment. The workload of secondary maintenance is between major repair and minor repair, and some repairs should be completed. It is mainly used to repair or replace the wear and damage of the vulnerable parts of equipment. The second-level maintenance needs to complete all the work of the first-level maintenance, and also requires cleaning all lubricating parts, and checking the quality of lubricating oil in combination with the oil change cycle, and cleaning and oil change. Check the dynamic technical status and main accuracy (noise, vibration, temperature rise, surface roughness, etc.) of the equipment. ), adjust the installation level, replace or repair parts, clean or replace motor bearings, and measure insulation resistance. After the second overhaul, the accuracy and performance requirements meet the process requirements, and there is no oil leakage, leakage and leakage, and the sound, vibration, pressure and temperature rise meet the standards. Before and after the secondary maintenance, the dynamic and static technical conditions of the equipment should be determined, and the maintenance records should be made carefully. The secondary maintenance is mainly composed of professional maintenance personnel and operators. (4) Establish a three-level maintenance system for equipment.
In order to standardize the three-level maintenance of equipment, the maintenance cycle, maintenance content and maintenance category list of each component should be made according to the wear, performance, accuracy deterioration and the possibility of failure, which is the basis of equipment operation and maintenance. An example of equipment maintenance plan is shown in table 1, where "ο" means maintenance inspection. Due to the different maintenance categories and contents in different periods, in practice, different symbols can be used to represent different maintenance categories, such as "ο" for daily maintenance, "△" for primary maintenance and "▽" for secondary maintenance. Table 1 Example Table of Maintenance Plan for Mechanical Equipment Parts
Basic contents of equipment maintenance
The basic contents of equipment maintenance include: equipment maintenance, equipment inspection and equipment repair. Details are as follows. I. Equipment maintenance
The content of equipment maintenance is to keep the equipment clean, tidy, well lubricated and safe, including fastening loose fasteners in time and adjusting the clearance of moving parts. In short, it is the cross operation method of "cleaning, lubricating, fastening, adjusting and anticorrosion". Practice has proved that the service life of equipment largely depends on the maintenance quality. According to the workload and difficulty, maintenance is divided into daily maintenance, primary maintenance, secondary maintenance and tertiary maintenance.
Daily maintenance, also known as routine maintenance. Its main contents are: cleaning, lubricating, fastening loose parts and checking the integrity of parts. There are few maintenance items and parts, most of which are outside the equipment.
The first-class maintenance mainly includes: general fastening, cleaning, lubrication, fastening and local adjustment. Daily maintenance and primary maintenance are generally undertaken by operators.
Secondary maintenance. The main contents include internal cleaning, lubrication, partial disintegration inspection and adjustment.
Three-level maintenance. It is mainly to disassemble, inspect and adjust the main parts of the equipment, and replace the parts that reach the specified wear limit when necessary. In addition, it is necessary to measure, identify and record the wear of major components. Secondary maintenance and tertiary maintenance are generally carried out by full-time maintenance personnel with the participation of operators.
In all kinds of maintenance, daily maintenance is the foundation. According to the characteristics of different equipment, the categories and contents of maintenance should be specified, and the specific conditions and characteristics of equipment such as production technology, structural complexity and scale should be considered, as well as the long-term maintenance habits of different industrial enterprises.
Second, the equipment inspection
Equipment inspection refers to measuring and verifying the operation, working accuracy, wear or corrosion degree of equipment. Through inspection, we can fully grasp the technical status and wear of mechanical equipment, find and eliminate hidden dangers of equipment in time, make preparations before repair purposefully, improve repair quality and shorten repair time.
Inspection is divided into daily inspection and regular inspection according to time interval. The daily inspection is carried out by equipment operators, combined with daily maintenance, with the purpose of finding abnormal technical conditions in time and carrying out necessary maintenance work. With the participation of operators, full-time maintenance personnel will conduct regular inspections according to the plan. The purpose is to comprehensively and accurately grasp the actual situation of parts wear through inspection, so as to determine whether it is necessary to repair.
According to technical functions, inspection can be divided into functional inspection and accuracy inspection. Functional inspection refers to the inspection and determination of various functions of equipment, such as oil leakage, water leakage, air leakage, dust sealing, high temperature resistance, high speed and high pressure of parts, etc. Accuracy inspection refers to the inspection and determination of the actual machining accuracy of equipment, so as to determine the quality of equipment accuracy and provide basis for equipment acceptance, repair and update. Third, equipment repair.
Equipment repair refers to the repair of equipment damage and accuracy deterioration caused by routine or abnormal reasons. By repairing and replacing worn, aged and corroded parts, the equipment performance can be restored. Equipment repair and maintenance are different aspects of equipment maintenance. Because the work content and function are different, they can't replace each other. They should be done at the same time, so as to cooperate with each other and complement each other.
1, equipment maintenance type. According to the repair scope, repair interval and repair cost, equipment repair can be divided into three categories: minor repair, medium repair and major repair.
(1) minor repairs. Minor repairs usually only need to repair and replace some parts with fast wear and service life equal to or less than the repair interval, adjust the local structure of the equipment, and ensure the normal operation of the equipment until the scheduled repair time. Minor repairs are characterized by frequent maintenance, small workload and short maintenance time, and maintenance costs are included in the property cost. Minor repairs are generally carried out by full-time project maintenance workers.
(2) medium repair. Repair refers to the partial disassembly of equipment, repair or replacement of some main parts and benchmark parts, or repair of parts with service life equal to or less than the repair interval of 2. At the same time, it is necessary to inspect the whole mechanical system, tighten all parts, eliminate the enlarged gap, and calibrate the equipment benchmark to ensure that the mechanical equipment can be restored and meet the due standards and technical requirements. The characteristics of repair are: more repair times, less workload and short repair time, and the repair cost is included in the maintenance fund 2. Most maintenance projects are carried out by full-time maintenance workers on the equipment site, and some projects with higher requirements can be undertaken by non-professional units. After the repair, the inspection and acceptance shall be organized, and the repair unit and the repair unit shall handle the handover procedures.
(3) major repairs. Overhaul refers to a comprehensive repair to restore the original accuracy, performance and production efficiency of the equipment by replacing and restoring its main components. Major repairs are characterized by less repairs, heavy workload and long repair time, and the repair costs are paid by the overhaul maintenance fund. After the overhaul of equipment, the quality management department and the equipment management department shall organize the relevant personnel of the user and the contractor to carry out the acceptance, and send them to the repair unit and the contractor for handover procedures after passing the acceptance. 2, the method of equipment repair
Commonly used equipment repair methods mainly include the following:
(1) The standard repair method, also known as the forced repair method, refers to the preparation of a specific repair plan in advance according to the service life of equipment parts, and clearly stipulates the repair date, category and content of equipment. When the equipment runs to the specified time limit, it must be repaired according to the specified scope and requirements, regardless of its technical status and tasks. This method is conducive to the preparation before maintenance and effectively ensures the normal operation of the equipment, but sometimes it will cause excessive maintenance and increase the maintenance cost.
(2) Regular repair method refers to the fixed order, planned repair interval and repair workload of various planned repairs in advance according to the service life of parts, production type, workpiece condition and relevant quota data. Before maintenance, the maintenance content is usually determined according to the state of the equipment. This method is conducive to the preparation before repair, and the advanced repair technology is adopted to reduce the repair cost. (3) Repair after inspection means that only the number and time of inspection are specified in advance according to the wear data of equipment parts, and the specific cycle, category and content of each repair are determined by the results after inspection. This method is simple and easy to operate, but due to poor repair plan and subjective judgment error of equipment condition during inspection, it may cause excessive wear or failure of parts.