The characteristics of the fault In view of the various […]
The characteristics of the fault
In view of the various fault source factors, the actual faults of the equipment (especially the difficult faults) often have the characteristics of concealment, randomness and recurrence to different degrees.
The evolution of the fault in time from the incubation period, the development period to the damage period, there is a development process from concealment to exposure, and it is finally noticed by people, but the initial cause is often difficult to find. The spread of faults in space is also from the local to the whole. After the accident, people often ignore the root cause of the micro-mechanism. The concealment of the fault originator in time and space makes the analysis of the fault very difficult, so people put forward the stage problem of fault finding and the hierarchical problem of fault location. The initiating end of a single fault goes from the incubation period to the development period, and then from the development period to the damage period, that is, the beginning and the end of the three periods of evolution should have clear objective signs.
The randomness of the failure of the entire equipment comes from the randomness of zero (element) component failures (machines and equipment), the randomness of the combination of component failures, the discreteness of materials and manufacturing processes, the randomness of operating environment and working conditions, and Randomness of maintenance status. The pros and cons of materials and manufacturing processes determine the degree of influence of zero (element) parts on the occurrence of failures, so its discreteness will inevitably lead to the randomness of the time and degree of failure. The randomness of the operating environment and working conditions, even for the same equipment, its failure frequency and service life will vary greatly due to the different strengths of the destructive factors it withstands. The influencing factors of the maintenance status are: ①Maintenance decision and implementation plan vary from person to place; ②The condition of spare parts is different; ③The repair process, equipment, and materials are different; ④Early or delayed maintenance caused by different maintenance systems.
The frequent occurrence of failures is a combination of subsequent failures and concurrency. For the actual parts, especially the assembly and the whole machine, a single fault develops to a certain extent. If it is not eliminated in time, it is likely to cause another (or several) faults. The caused fault may also cause other faults. The failure causal chain. However, in general, from the development and change period to the occurrence of the failure, not all factors in all aspects are manifested at the same time, but only a single factor or one or two factors play a major role. Some textile manufacturers that have carried out conditional maintenance for many years estimate that single-factor failure sources account for about 80%-95%. As long as the diagnosis is accurate and eliminated in time, multiple failures will not be caused. Therefore, the cause and characteristics of the failure can be recognized and mastered.
Equipment failures can also be divided into preventable and unpreventable categories. If there are many preventable failures, it means that the preventive maintenance of the equipment is not in place; if there are too many preventable failures, it means that the reliability of the equipment itself is poor and the technical level is not high. We control and reduce equipment failures, mainly from improving preventive maintenance capabilities, and designing and manufacturing equipment must pay attention to its reliability at the same time.