Three major problems in factory equipment management and corresponding solutions

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Preface: In a company’s production activities, equipment maintenance is an important measure to ensure the safe operation of the equipment； It is an effective means to restore the technical performance of equipment, eliminate faults and potential failure risks, and extend the service life of the equipment. China’s equipment maintenance industry started relatively late, and there are still many technical and methodological issues in this field. The existence of these problems leads to poor quality in equipment maintenance, low reliability of the equipment, and even serious equipment accidents. I. Problems existing in equipment maintenance methods 1. Faults cannot be properly diagnosed and analyzed during equipment maintenance, and the practice of carrying out unnecessary and extensive disassembly is quite common. Some maintenance workers, due to their lack of understanding of the mechanical structure and principles of the equipment, fail to analyze the causes of faults carefully or determine the location of the problems accurately. Acting on a guesswork approach, they disassemble the equipment recklessly; as a result, not only are the original faults not resolved, but new problems also arise because of their poor maintenance skills and techniques. For example, at one station, there was a problem where the 120KW diesel generator did not have sufficient power, resulting in the machinery being unable to operate. The maintenance technicians disassembled the PT fuel pump and injectors but were unable to find the cause of the fault; they tried replacing one fuel pump, yet the problem persisted. The final inspection revealed that the fault was caused by internal impurities and excessive moisture in the diesel used. However, this disassembly resulted in a significant decline in the performance of the PT fuel injection pump, leading to insufficient power output from the diesel generator. Therefore, when a mechanical failure occurs, it must be inspected using testing equipment ； In the absence of testing equipment, traditional fault diagnosis methods and techniques such as asking questions, observing, checking, and testing can be used, in combination with the device’s structure and working principles, to determine the area most likely to be faulty. When diagnosing equipment failures, the \"elimination method\" and the \"comparison method\" are generally used, following a sequence from simple to complex, from the exterior to the interior, and from assemblies to individual components. It is important to avoid reckless disassembly without first understanding the situation. 2. The phenomenon of blindly replacing parts and relying solely on \"part replacement repairs\" exists to varying degrees. Determining and troubleshooting equipment failures can be somewhat difficult. Some technicians consistently use the method of replacing components one by one; regardless of whether they are large or small components, any part that might be causing the failure is tested by replacing it. As a result, not only was the fault not resolved, but unnecessary parts were also replaced arbitrarily, increasing the repair costs. Some faulty components can have their technical performance restored entirely through repair; for instance, faults in generators, air compressors, blowers, burners, gear oil pumps, etc., can be fixed without the need for complex repair procedures. During maintenance, the cause and location of the fault should be carefully analyzed based on the symptoms exhibited. For those components that can be repaired, repair methods should be employed to restore their technical performance, avoiding the practice of replacing components blindly. 3. There are quite a number of cases where the fit clearance of components is not properly checked. In the maintenance of common diesel generators, there are strict requirements for various parameters such as the clearance between the piston and cylinder liner, the \"three clearances\" of the piston rings, the clearance at the top of the piston, valve clearances, plunger clearances, brake shoe clearances, the meshing clearance between the driving and driven gears, the axial and radial clearances of bearings, and the clearance between the valve stem and valve guide. These parameters must be measured during maintenance, and any components that do not meet the specified clearances need to be adjusted or replaced. In actual maintenance work, there are many cases where components are assembled blindly without measuring the clearance, which leads to problems such as premature wear or ablation of bearings, oil leakage from diesel generators, difficulty starting or detonation, broken piston rings, component collisions, oil leaks, and air leaks. Sometimes, even improper clearance between components can lead to serious mechanical damage. 4. It often happens that components are installed in the wrong order during equipment assembly. When repairing equipment, some components have strict orientation requirements for assembly ； Only proper installation can ensure the proper functioning of the components. Some components do not have distinct external features, allowing them to be installed on either side; in practical use, it is common for them to be installed incorrectly, which leads to premature damage of the components, malfunction of the machinery, and equipment failure. Components such as engine cylinder gaskets, unevenly spaced valve springs, engine pistons, piston rings, fan blades, gear oil pump side plates, skeleton oil seals, thrust washers, thrust bearings, thrust shims, oil retaining rings, fuel pump plungers, clutch friction disc hubs, and drive shaft universal joints are most prone to being installed incorrectly if the structure and installation requirements are not understood. This causes abnormal operation after assembly, leading to equipment failures. Therefore, when assembling components, maintenance personnel must understand the structure of those components as well as the requirements regarding their installation direction, and must not proceed with installation blindly without proper understanding. 5. The repair methods are not proper; “*****” remains a common practice among some repair firms. When repairing equipment, some technicians do not use the correct methods; they think that emergency measures are a solution to everything, replacing proper repairs with emergency fixes. Such problematic practices are still very common. A common example is the practice of using welding as a substitute for repair. Some components could have been repaired, but some technicians, in search of convenience, often opt for the method of welding them in place ； To make the diesel generator more powerful, the fuel supply volume from the fuel injection pump is artificially increased, as well as the injection pressure of the injectors. These informal repair methods can only be used as a temporary solution; they cannot be employed in the long term. It is necessary to identify the root cause of the fault and use proper repair methods to fix it, and maintenance personnel should be aware of this. II. Problems with equipment maintenance materials and spare parts 1. The quality of new parts is not checked, and failures occur quite frequently after assembly. Before replacing parts, some technicians fail to conduct a technical inspection of the new parts; they simply install them on the equipment right away, and this approach is unscientific. The quality of spare parts available on the market varies greatly; some fake and substandard parts are mixed in among them ； There are also some accessories whose performance changes due to being in stock for too long; if not tested, they often cause malfunctions after being installed. Therefore, it is essential to conduct the necessary inspection tests before replacing with new parts. The inspection includes visual and performance tests to ensure that the new components are fault-free and to prevent any unnecessary problems caused by them. 2. Attention is not paid to accessory models, and the substitution or misuse of accessories is quite common. When repairing equipment, the use of substitute parts or incorrect parts remains quite common. Some spare parts can be used as temporary substitutes, but using them for extended periods is harmful rather than beneficial, as it affects the safety and technical performance of the equipment. Some maintenance workers have little knowledge of mechanical structures and principles; many spare parts are of the wrong type, yet they think that as long as they can be installed, it’s fine, without considering whether the machine will be able to perform its technical functions properly ； Using defective items in place of qualified ones, wire or nails instead of split pins, and rebar or IEt bolts in place of cylindrical pins, etc., cannot ensure quality; their use over the long term is absolutely not permitted. Therefore, when repairing equipment, original model parts should be used as much as possible; alternative parts of other models must not be used, nor should the wrong parts be employed ； Unpaired or sets of replacement components are also not uncommon. The equipment consists of many components, such as the plunger assemblies in the diesel generator’s fuel system, the fuel outlet valve assemblies, and the injector needle valve components. These components are specially processed during manufacturing in the factory, where they are ground together in pairs to achieve a high degree of precision in their fit. They must always be used as a pair throughout their service life and must not be interchanged. Some components that work together, such as pistons and cylinder liners, as well as bearing shells and shaft journals, achieve a better fit after being used together for a while. During maintenance, it is also important to assemble them in pairs to avoid mixing them up. These machines use a set of accessories together; if any part gets damaged, the entire set must be replaced. Otherwise, due to differences in accessory quality, varying levels of wear and tear, and differences in length, the equipment may not operate properly, and the replaced accessories are likely to fail prematurely. In actual maintenance work, some people do so to cut costs, while others are unaware of the technical requirements; as a result, it is not uncommon for the aforementioned components to be replaced without being paired or in complete sets. This reduces the quality of equipment maintenance, shortens the lifespan of the components, and increases the likelihood of failures, an issue that deserves proper attention. 3. Gaskets are not used in a proper manner, and random use of them still persists. There are many types of gaskets used between the mating surfaces of equipment components; common ones include asbestos gaskets, rubber gaskets, cardboard gaskets, cork gaskets, felt gaskets, non-ferrous metal gaskets (copper gaskets, aluminum gaskets), copper/steel asbestos gaskets, insulating gaskets, spring washers, and flat washers. Some are used to prevent oil, water, air, or electricity leakage between the mating surfaces of components, while others serve to tighten and prevent loosening. There are different regulations and requirements regarding when and where each type of gasket should be used. When repairing equipment, the improper or even random use of gaskets is still a serious problem; this leads to leaks between the mating surfaces, as well as the loosening of bolts and nuts, thereby affecting the proper operation of the equipment. If the generator’s cylinder gasket is too thick, it results in a reduced compression ratio, making it difficult to start the engine ； Copper gaskets should be used between the injector and the cylinder head mating surface; using asbestos gaskets instead can lead to poor heat dissipation of the injector and subsequent ablation. Therefore, when maintenance personnel repair equipment, remember that \"gaskets may be small, but they are very useful.\" III. Problems regarding the quality of equipment maintenance 1. Insufficient attention is paid to the quality of \"minor components,\" and negligence due to their small size leads to an increase in failures. During equipment maintenance, some technicians tend to focus only on the upkeep of components such as pumps and fuel pumps, while neglecting the maintenance of various instruments and other \"small items\". They believe that these “minor components” do not affect the operation of the machine, and that it doesn’t matter if they get damaged; as long as the machine can still function, it’s fine to keep using it. What they don’t realize is that it is precisely the lack of maintenance of these “small components” that leads to premature wear of the machinery, thereby shortening its service life. Items such as the oil filter, air filter, hydraulic oil filter used in the equipment, water temperature gauge, oil temperature gauge, oil pressure gauge, sensors, alarms, filters, grease nozzles, return oil connections, split pins, fan shrouds, and drive shaft bolt locks are all such \"small components\" that are essential for the proper operation and maintenance of the equipment. They play a crucial role in extending the service life of machinery; failure to carry out proper maintenance can lead to serious problems and equipment failures. 2. Forget the maintenance taboos, and hidden faults will occur frequently. When repairing equipment, some technicians are unaware of certain issues that need to be taken into account during repairs, which leads to errors related to inertia during disassembly and assembly, thereby affecting the quality of the mechanical repairs. For example, when installing piston pins, if the piston is not heated and the pins are inserted directly into the pin holes, this causes an increase in the piston’s deformation and its ellipticity. When maintaining diesel generators, excessive scraping of the bearing shells results in the removal of the anti-friction alloy layer on their surfaces, leading to direct friction between the steel backing of the bearing shells and the crankshaft, which causes premature wear ； When removing components with interference fits such as bearings and pulleys, do not use pullers; forcing them by force can easily cause the components to deform or get damaged ； When opening new pistons, cylinder liners, fuel injector assemblies, plunger assemblies, and other components, using fire to burn the oil or wax that seals their surfaces can alter the performance of these components, which is not favorable for their use. 3. Inadequate cleaning and decontamination of parts lead to premature wear and corrosion. When repairing equipment, properly removing oil and contaminants from the surface of components is crucial for improving the quality of repairs and extending the service life of the machinery. Failing to pay attention to proper cleaning of components, using inappropriate cleaning agents, or employing incorrect cleaning methods can lead to premature wear and corrosive damage of these components. If the debris in the bolt holes and the sand particles in the hydraulic components are not thoroughly removed, it can result in insufficient bolt torque, easy breakage of piston rings, abrasion of cylinder gaskets, and premature wear of hydraulic components. During major repairs, if the oil residues or impurities accumulated in filters, lubrication channels, and other areas are not properly removed, the repair work will not be thorough, thereby reducing the equipment’s time of fault-free operation. When cleaning components, repair personnel must first choose the right cleaning agent. For the cleaning of various components, different cleaning agents should be selected appropriately based on their respective requirements regarding cleanliness ； Second, it is necessary to prevent components from corroding and rusting. To ensure the quality of components, it is necessary to prevent them from corroding or rusting; especially for precision components, any degree of corrosion or rusting is not allowed. Therefore, when cleaning, alkaline cleaners (especially strong alkaline cleaners) should not be used to clean aluminum alloy components, and strong acid cleaners should not be used to clean copper components, in order to minimize corrosion of the parts ； Third, different components should be cleaned separately. Aluminum alloy components and copper components should not be cleaned together in alkaline or acidic cleaners, while rubber components should not be cleaned together with other steel parts in gasoline, diesel, or acidic and alkaline cleaners.