【Sea and River Safety Discussion】A039 – How to Apply the “Bathtub Curve” in Safety Management? ? ?

The failure rate varies with time of use and can be divided into three stages: the initial failure stage, the random failure stage, and the wear-out failure stage. (1) Initial failure period. Defects in design and manufacturing ； The parts do not fit well together ； Equipment failures caused by moving, transporting, installing, or improper operation by the operator. There are many issues at this stage, and they become apparent quite quickly. As these problems are gradually resolved, the failure rate changes from high to low and tends to stabilize over time. (2) Period of occasional failures. When the equipment is operating normally, with a low and stable failure rate that remains essentially unchanged, this period is known as the optimal operating period of the equipment, as well as its effective service life. (3) Wear-out failure period. During this period, the failure rate of equipment increases sharply, mainly because after prolonged operation, the wear of certain components reaches an extreme level, their effective service life comes to an end, and the equipment is no longer in proper working condition.

Devices have different characteristics at various stages, so our maintenance strategies also vary at each stage. NO1. Equipment management during the initial failure period 01 Lubrication and lubricant management: The oil in equipment during its initial stage is prone to contamination by abrasive particles; therefore, it is necessary to determine appropriate timing for oil changes based on the equipment’s wear patterns. If contamination or darkening is detected, it should be replaced promptly, until the equipment enters a stage of slow wear – that is, by continuously monitoring the lubricant to ensure it remains at a high level of cleanliness. 02 Recording of equipment operation parameters: In the early stages of equipment operation, the process parameters and the interaction between various components are not very stable. At this point, various parameters inside and outside the equipment, including clearance, balance, position, temperature, humidity, vibration, and current conditions, all require a process of adjustment and adaptation. Inspections and records during this period are particularly important. 03 Tightening and Adjustment: In the initial stage of equipment operation, it is essential to conduct timely monitoring and fine adjustments with regard to aspects such as the clearance between components, the balance of the equipment, its tightening status, environmental temperature, humidity, vibration levels, shielding conditions, grounding status, load conditions, and the conditions after any updates to the product specifications. 04 Production load control: It is advisable to operate the equipment at a level below its designed production load during the initial phase of operation; this is an effective measure for protecting new equipment. NO2. Equipment management during periods of occasional failures 01 Routine maintenance: During such periods, it is crucial to carry out regular tasks such as cleaning, inspection, lubrication, adjustment, corrosion prevention, and leak sealing – these activities form the basis of all repair strategies. 02 Regular maintenance: For components with distinct wear cycles, a regular maintenance strategy based on part replacement is adopted. Regularly replace damaged bearings, corroded chemical containers, broken nuts, bolts, valves, electrical components, connectors, etc. 03 Health management: Focus on understanding the evolution, characteristics, and patterns of microscopic and dynamic damage in machinery, and implement effective preventive measures, ongoing monitoring, as well as dynamic maintenance and repair. NO3. Equipment management during the wear and failure period: During this period, in addition to carrying out regular maintenance tasks such as cleaning, inspection, lubrication, adjustment, and tightening, corrective repairs must be carried out on those parts that have suffered severe wear and deterioration. A customizable and modular maintenance approach is adopted to restore equipment functionality through part replacement or repair and rejuvenation; for assemblies or units showing no signs of damage, there is no need for disassembly, inspection, or replacement.

Move forward with the work, focusing on maintenance strategies throughout the entire lifecycle. Prevention first and a combination of prevention and control are also applicable to the health management of equipment. Move forward with the work, adhering to the three prevention principles of \"preventing diseases before they occur, preventing their progression once they have arisen, and preventing recurrence after recovery,\" which include early maintenance for prevention. That is, to emphasize the verification of equipment reliability and maintainability during the equipment selection, design, and manufacturing stages. Strengthen and upgrade the structure or material coating of the equipment during the manufacturing phase, or after purchase. Intermediate preventive maintenance. Standardized operations and continuous improvement ； Eliminate defects and potential hazards in the equipment ； Investigate similar devices that have failed in order to eliminate potential hazards. Urgent repair and reinforcement during the failure period. Use new materials and technologies to carry out rapid reliability repairs on faulty equipment ； Green remanufacturing is carried out on the replaced spare parts.

Move forward with the work, focusing on maintenance strategies throughout the entire lifecycle. Prevention first and a combination of prevention and control are also applicable to the health management of equipment. Move forward with the work, adhering to the three prevention principles of \"preventing diseases before they occur, preventing their progression once they have arisen, and preventing recurrence after recovery,\" which include early maintenance for prevention. That is, to emphasize the verification of equipment reliability and maintainability during the equipment selection, design, and manufacturing stages. Strengthen and upgrade the structure or material coating of the equipment during the manufacturing phase, or after purchase. Intermediate preventive maintenance. Standardized operations and continuous improvement ； Eliminate defects and potential hazards in the equipment ； Investigate similar devices that have failed in order to eliminate potential hazards. Urgent repair and reinforcement during the failure period. Use new materials and technologies to carry out rapid reliability repairs on faulty equipment ； Green remanufacturing is carried out on the replaced spare parts.