Possible failures and diagnosis steps of the hydraulic system of the injection molding machine

When using an injection molding machine, the possible failures of the hydraulic system of the injection molding machine are diverse. It is the result of a combination of many factors, and the dispersion is relatively large. Samakatuwid, when performing fault diagnosis, it is necessary to analyze the factors that cause the fault one by one, pay attention to their internal connections, and find out the main contradictions, so that they can be resolved relatively easily.

Under normal circumstances, the failure of the hydraulic system of the injection molding machine is not accidental. Any failure will be accompanied by various abnormal signs before it evolves into a major failure. These signs can be summarized as:

(1) There are abnormal sounds, such as pumps, motors, and thermostatic valves.
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(2) The operating speed of the hydraulic motors for slewing, walking, and hoisting, as well as the hydraulic cylinders of various working devices, is reduced and weak.
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(3) The oil tank level drops and the oil deteriorates.
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(4) Oil leakage occurred on the outer surface of hydraulic components.
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(5) The oil temperature is too high.
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(6) Pipeline damage, looseness and vibration occur.
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(7) The smell of focal nucleus appears and so on.
All of the above phenomena can be discovered by naked eye observation, hand touch, and nose smell as long as you pay careful attention during use. In actual work, people use this on-site method as the first-hand information to analyze the failure, and then based on experience, synthesize these first-hand information to analyze the actual problem and find out the cause of the failure as early as possible. Be resolved.

Gayunpaman, in actual work, it is often impossible to accurately diagnose the cause of the failure at one time. Sa panahong ito, several iterations are required, iyon ay, repeated analysis and repeated inspections until the cause of the failure is found.

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In actual work, engineering and technical personnel often follow the following steps to deal with faults in the hydraulic system.
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(1) Understand the system
When a certain iniksyon paghuhulma machine has a hydraulic failure, you should first understand the hydraulic system. It is to be familiar with the relevant technical data and reports, understand the working principle of the liquefied gas pressure system, understand the basic structure of various components and the specific functions in the system, and be able to find out the liquid flow process under various working conditions. Before inspecting the equipment, observe the working conditions of the system and record the necessary technical data, such as working speed, pressure, flow, cycle time, atbp.
(2) Ask the operator
Interrogate the operator operating the malfunctioning injection molding machine. Ask about the characteristics of the equipment and its functional characteristics; ask about the basic phenomena when the equipment fails, such as whether the hydraulic pump can be started, whether the system oil temperature is too high, whether the system noise is too high, whether the hydraulic cylinder can drive the load, atbp.
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(3) Verify the phenomenon provided by the operator and check carefully
The phenomenon proposed by the operator is further verified by observing the meter readings, working speed, listening to the sound, checking whether the oil and actuators have malfunctions, atbp.; then, according to the fluid flow in the system, look carefully along the loop from the tank in turn, and on time Record the observation.

During the inspection, carefully check the oil in the fuel tank to determine whether dirt enters the system. Affect the normal operation of each component of the system; touch it by hand to check whether the oil inlet pipe and high-pressure oil pipe are proliferated, softened, leaked, or damaged; check the pipe joints of the control components and the mounting screws of the housing if they are loose; finally check the oil and Piston rod of hydraulic cylinder. In each step of the inspection, attention should be paid to whether there is improper operation or maintenance to find the cause of the failure.
(4) List the possible causes of failure based on the information obtained from understanding, inquiry, verification and inspection
Sa panahong ito, it should be kept in mind that a failure phenomenon may be caused by two or more reasons. Halimbawa, the speed of the actuator may decrease, which may be due to the wear of hydraulic pump parts, or the internal leakage of the hydraulic cylinder may increase; halimbawa, If the oil temperature is too high, it may be that the amount of oil in the oil tank is not enough, or that the oil pollution blocks the heat dissipation surface, or the pressure of the overflow valve is adjusted too high.
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(5) Make a conclusion
According to the list of failure causes, the inspection sequence is arranged according to the principle of “easy first and then difficult”. First select those that can be restored to normal after a simple inspection or repair, so that the inspection work can be completed in the shortest time.
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(6) Verification conclusion
Once through the above steps, find out the cause of the failure of the injection molding machine, start troubleshooting. Troubleshooting includes checking pressure and flow with appropriate test equipment, disassembling the casing cover, and checking pumps, motors and other components. These test inspections are the basis for judging the replacement of parts and hydraulic components. In actual work, there is often no suitable test device to carry out inspections. Sa panahong ito, it is necessary to replace the pump, motor, hydraulic valve and other component assemblies as an effective means of troubleshooting.In the process of finding and troubleshooting faults, you should be careful, careful, cautious, and strive to be accurate, avoid blindly disassembling parts, or use improper methods to deal with faults, so as to avoid new damages caused by this. Except when necessary, do not easily disassemble the hydraulic components, because unnecessary and premature disassembly and assembly will reduce the service life of these components.

The ideal working temperature of the hydraulic system should be between 45 degrees and 50 mga degree. The reason is that the hydraulic system is designed according to a selected pressure oil viscosity, but the viscosity will change with the oil temperature, which will affect the work in the system. Components, such as oil cylinders, hydraulic valves, atbp., reduce control accuracy and response sensitivity, especially for precision injection machines.
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Kasabay nito, if the temperature is too high, it will accelerate the aging of the seal and cause it to harden and crack; if the temperature is too low, the processing energy will be consumed and the operating speed will decrease. Samakatuwid, it is necessary to pay close attention to the working temperature of hydraulic oil. There are many reasons for the high oil temperature, but most of them are due to the failure of the oil circuit or the failure of the cooling system.
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Insufficient oil will cause the oil temperature to rise easily, and the air will easily dissolve into the oil, which will affect the oil quality and the normal operation of the hydraulic system. Insufficient oil is usually caused by oil leakage or loss during repairs. Para sa kadahilanang ito, you should pay attention to check whether there is any leakage. Kung kinakailangan, replace worn seals and tighten loose joints as soon as possible. After maintenance, check the amount of oil in the tank and replenish it in time.

One of the important properties of hydraulic oil is its chemical stability, iyon ay, oxidation stability. Oxidation is the most important factor that determines the effective service life of hydraulic oil. The insoluble matter such as wood tar, sludge and carbon residue generated by oxidation will contaminate the hydraulic system, increase the wear of hydraulic components, reduce various gaps, block small holes, and eventually cause The hydraulic system is malfunctioning.

The oxidation rate of hydraulic oil depends on many factors such as itself and working conditions, among which temperature is one of the main factors. Samakatuwid, it is necessary to use suitable hydraulic oil and regularly check the oxidation degree of the hydraulic oil (judged from the darker color of the oil itself) ), it is absolutely necessary to actively change the oil after a certain number of working hours.　　
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During the use of the iniksyon paghuhulma machine, always check the pressure oil level, the pressure of the oil pump and the cleanliness of the pressure oil. When encountering wet weather, the concentration of the pressure oil must be checked daily, and the water pipes must be checked frequently to prevent water from being mixed in. In the pressure oil, the oil filter is blocked. Check the fuel tank frequently to keep it clean to prevent debris from falling in. Replenish pressure oil on time.
For the lubrication of the moving parts, the travel switch, the tightening of the screws, and whether the oil hoses and joints are leaking, they should be routinely checked once a week to keep them in good condition. If they are loose, they should be replaced or tightened.　　
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Sa karagdagan, if a pressure oil is used for too long or too long, the pressure oil can be replaced, so as to extend the life of the oil switch, oil pump and sealing ring.