“If you want to do a good job, you must first sharpen your tools.” Good equipment plays a vital role in production efficiency. However, during long-term use, the wear of mechanical parts, enlarged clearances and changed fits directly affect the original balance of the equipment. The stability, reliability and operating efficiency of the equipment will all decline to a certain extent, and the machinery may even lose its inherent basic functions and fail to operate normally.
For this reason, it is necessary to establish a scientific and effective equipment management mechanism, strengthen daily equipment management, combine theory with practice, and formulate scientific and reasonable equipment maintenance and care plans.
I. Use of Equipment
(1) Operation with a certificate
Before operating independently, operators must receive education in basic technical theory and practical operation skills training. Only after passing the assessment and being issued the operation certificate may they operate the machine independently. The operation certificate is issued uniformly by the equipment management department and should clearly state the machine models the operator is qualified to operate.
(2) Fixed operator for fixed machine
To strictly implement the post responsibility of operators, ensure correct use of equipment and implement daily maintenance work, a “fixed person, fixed machine” system should be adopted. The equipment post responsibility system should define the operator’s basic duties, basic rights, the basic requirements they should know and be able to perform, and the reward methods. Public equipment should have designated maintenance personnel with clear maintenance responsibility. Equipment operated by multiple people adopts a machine leader system, with the machine leader responsible for the use and maintenance of the equipment.
(3) Shift handover system
Important equipment running continuously in multiple shifts should adopt a shift handover system. The handover person must record in detail the problems found during equipment operation in the shift handover log, proactively introduce the equipment operating status to the incoming person, check together on site, and sign the log after handover. If the incoming person finds abnormal equipment conditions, unclear records, unknown situations, or equipment not maintained as required, they may refuse to take over. If problems occur after taking over due to an unclear handover, the incoming person is responsible.
If handover cannot be done face to face, the outgoing person may complete the daily maintenance, keep the equipment in a safe state, fill in the handover record and ask the relevant person in charge to sign for acceptance. The shift handover log must not be torn or altered. Maintenance personnel should promptly collect the shift handover logs, analyze the equipment status from them, and take measures to improve maintenance work. The equipment management department and workshop leaders should pay attention to spot-checking the implementation of the shift handover system.
(4) Develop equipment operation and maintenance procedures
For precision, large and scarce equipment, main equipment, and safety-related equipment, equipment operation and maintenance procedures should be developed. They generally include the following:
1) Requirements for site cleaning before operating the equipment.
2) Tools and appliances that must be used to operate the equipment.
3) Startup operating procedures and precautions.
4) Main process parameters of equipment operation.
5) Content and requirements of equipment status checks (when necessary).
6) Lubrication methods and requirements.
7) Items, content and frequency of spot checks and maintenance.
8) Shutdown procedures and precautions, and post-shutdown requirements.
9) Use and adjustment requirements of safety protection devices.
10) Causes of common faults and how to eliminate them.
11) Detailed shift handover work and record content.
(5) The “Four Requirements” in equipment use
1) Neatness: tools, workpieces and accessories placed neatly, safety protection devices complete, lines and pipes intact.
2) Cleanliness: inside and outside of the equipment clean, no “yellow robe” oil stains, all sliding surfaces, lead screws, racks and gears free of oil dirt and damage, and no water or oil leakage in any part.
3) Lubrication: refuel and change oil on time, oil quality meets requirements, oil cans, oil guns and oil cups complete, oil felt and oil lines clean, oil level indicators bright, oil circuits unobstructed.
4) Safety: implement the fixed-person fixed-machine and shift handover systems, comply with operating procedures, use equipment reasonably, monitor for abnormalities, and prevent accidents.
(6) The “Five Disciplines” in equipment use
1) Use equipment with an operation certificate and comply with safe operating procedures.
2) Keep the equipment clean at all times and refuel as specified.
3) Comply with the equipment shift handover system.
4) Manage tools and accessories well and do not lose them.
5) Stop immediately if any abnormality is found; problems that cannot be handled by yourself should be promptly reported to relevant personnel for inspection and handling.
(7) The “Four Skills” requirements for equipment users
1) Can use: operators should learn the equipment operating procedures and, after internship and obtaining the operation qualification certificate, operate independently.
2) Can maintain: learn and implement daily maintenance and lubrication regulations, and keep the equipment clean and intact.
3) Can inspect: understand the equipment structure, performance and easily worn parts, know the basic knowledge of normal and abnormal equipment, and work with maintenance workers to inspect and identify problems.
4) Can troubleshoot: be familiar with the equipment characteristics, know the precautions for disassembly and assembly, be able to make general adjustments, and work with maintenance workers to eliminate faults.
(8) The “Three Goods” requirements for equipment management
1) Manage equipment well: equipment is under dedicated custody and cannot be used or modified without approval.
2) Use equipment well: conscientiously implement the operating procedures and do not use the equipment beyond its rated load.
3) Maintain equipment well: operators should cooperate with maintenance workers to promptly eliminate equipment faults.
(9) Make equipment status labels
1) Equipment that is idle for a long time but not scrapped should be sealed and hung with an “Idle Equipment” sign.
2) Equipment under inspection needs a red inspection sign; the equipment power switch should be pulled down and a “Do Not Close Switch” warning sign hung.
3) Scrapped equipment needs a black scrapped sign.
4) Equipment in good working condition on site generally needs no additional labeling.
(10) Equipment operation records
For large and precision equipment (Class A equipment), necessary equipment operation records should be made.
II. Equipment Maintenance
1. Difference between preventive maintenance and predictive maintenance
(1) Preventive maintenance: planned maintenance activities carried out to prevent possible failure of the equipment and maintain its normal capability.
(2) Predictive maintenance: maintenance activities carried out by predicting possible equipment failure modes through data obtained from process monitoring and equipment monitoring.
2. Preventive maintenance (three-level maintenance system)
The main content of equipment maintenance is: cleaning, inspection, lubrication, fastening, adjustment, anti-corrosion, neatness and safety. According to the workload and difficulty, equipment maintenance can be divided into three levels:
(1) Daily maintenance
Daily maintenance is mainly carried out by operators, who are responsible for the daily cleaning, refueling according to the lubrication chart, inspection of loose parts and basic care of the equipment. The specific content includes: cleaning the equipment before work, refueling as specified, observing the equipment operating status during work, promptly handling minor abnormalities, and after work cleaning the equipment and accessories, arranging tools and keeping the site tidy.
(2) First-level maintenance
First-level maintenance is mainly done by operators, with maintenance workers providing guidance (or it may be done entirely by operators). Its technical requirements are higher, and the content mainly includes: partial disassembly and inspection of the equipment, cleaning of designated parts, and oil change of the lubricating parts.
(3) Second-level maintenance
Second-level maintenance is mainly done by maintenance workers, with operators cooperating and assisting (or it may be done entirely by maintenance workers). The technical requirements of second-level maintenance are high, and the content is as follows:
1) Partial disassembly, inspection and repair of the equipment.
2) Clean and change the oil of each main spindle box, transmission box, hydraulic box and cooling box.
3) Repair or replace easily worn parts and do partial scraping.
4) Inspect the electrical boxes, repair the wiring, and clean the electric motors.
5) Inspect, adjust and restore accuracy, and correct the levelness. And so on.
After second-level maintenance is completed, the inspection record should be filled in in detail and acceptance should be carried out. Second-level maintenance must ensure that the main accuracy reaches the process requirements; if some accuracy is difficult to restore, it can be postponed to the next major repair. The cycle of second-level maintenance depends on the specific condition of the equipment (generally, second-level maintenance should be carried out once after every 2,500 hours of operation).
Second-level maintenance can be regarded as scheduled repair.
Note 1: Major repair of equipment. Major repair is a kind of planned repair with the largest workload. It requires completely disassembling the equipment, comprehensively inspecting, repairing or replacing all worn parts, calibrating and adjusting the whole equipment system, and fully restoring the equipment’s original accuracy, performance, productivity and appearance (including repainting the exterior). Major repair can be combined with the technical renovation of the equipment. In some books, “major repair” and “second-level maintenance” are grouped together and collectively called “second-level maintenance”.
Note 2: The content of the above three-level maintenance system includes the content of equipment spot checks, achieving the combination of daily spot checks with daily maintenance, weekly and periodic spot checks with first-level maintenance, and accuracy checks with second-level maintenance. Therefore, there is no need to separately describe equipment spot checks.
Note 3: The content of the above three-level maintenance system already includes the content of minor repairs and medium (item) repairs in the traditional sense, so under this system there is no need to separately list minor repair and medium (item) repair items.
Note 4: The above maintenance mechanism contains the content of spot checks. Problems found in spot checks should be repaired promptly or arranged for planned repair. Therefore, within the intervals of the periodic first- and second-level maintenance, a certain number of planned repairs should be arranged as needed. Alternatively, the timing of first- and second-level maintenance can be left flexible and determined according to the inspection of the equipment condition (in this case it is called predictive maintenance). Of course, equipment spot checks can also be carried out independently. Generally, annual and monthly plans should be made for first- and second-level maintenance, listing the maintenance items, content and time.
Note 5: The above planned maintenance system can be regarded as: maintenance (daily maintenance, first-level maintenance, second-level maintenance) — timely planned repair — major repair.
3. Predictive maintenance
Predictive maintenance refers to maintenance activities carried out by predicting possible equipment failure modes through data obtained from process monitoring and equipment monitoring. It can be seen that the maintenance items and content of predictive maintenance are not fixed; therefore, the items and content of maintenance should be listed in the predictive maintenance plan. Generally, a predictive maintenance plan is made once a month, and it can also be formulated in a timely manner.
III. Equipment Lubrication
The “Five Fixed” management and “Three Filtration” of equipment lubrication standardize and institutionalize the daily lubrication technical management work, and are effective methods to ensure good lubrication work. Equipment lubrication work is carried out together with other equipment maintenance work.
(1) The “Five Fixed” management of lubrication
1) Fixed point: refuel, add oil, change oil, check the liquid level and oil supply at the designated parts, lubrication points and check points (oil level sight holes) according to the lubrication chart.
2) Fixed quality: determine the type, grade and quality requirements of the oil needed at the lubrication parts. The oil added must pass testing. When using substitute materials or blends, there must be a scientific basis. Lubrication devices and tools should be complete and clean to prevent oil contamination.
3) Fixed quantity: carry out daily lubrication of each lubrication part according to the specified quantity, implement oil consumption quota management, and do a good job of adding oil, refueling and cleaning/refilling the oil tank.
4) Fixed period: refuel according to the intervals specified on the lubrication card, and carry out sample testing at the specified intervals.
5) Fixed person: according to the division of labor specified in the chart, operators, maintenance workers and lubrication workers are respectively responsible for refueling, adding oil, cleaning and changing oil, and designated personnel are responsible for sampling and sending for testing.
The equipment department should compile a “Five Fixed” management specification table, specifying in detail which equipment, which part, what oil to use, how long the oil change (refueling) cycle is, what refueling device to use, and who is responsible.
(2) The “Three Filtration” of lubricating oil
To truly ensure the cleanliness of lubricating oil, necessary three-level filtration should be carried out, as follows:
1) Filtration at storage: filter the oil when it is put into the oil storage tank.
2) Filtration at dispensing: filter the oil when it is dispensed into the lubrication container.
3) Filtration at refueling: filter the oil when it is added to the oil storage part of the equipment.