Injection molding machine is one of the commonly used equipment in the plastics processing industry. It usually takes a long time to work. Therefore, how to ensure the normal and stable operation of the injection molding machine in continuous production is a worthy consideration for both the injection machine manufacturer and the user. To solve the problem, from the user's point of view, on the premise of correct selection of the injection model, regular preventive maintenance is an effective way to ensure the normal operation of the injection machine. Below, Lisong Machinery will introduce to you what are the preventive maintenance of injection molding machines and the common troubleshooting methods:
Preventive maintenance work of the hydraulic part of the injection molding machine:
1. Hydraulic oil volume
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. For this reason, you should pay attention to check whether there is any leakage. If necessary, replace worn seals and tighten loose joints as soon as possible. After maintenance, check the amount of oil in the fuel tank and replenish it in time.
2. Hydraulic oil temperature
The ideal working temperature of the hydraulic system should be between 45℃-50℃, because 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 of the system. Components, such as oil cylinders, hydraulic valves, etc., reduce control accuracy and response sensitivity, especially for precision injection machines.
At the same time, too high temperature will accelerate the aging of the seals and cause them to harden and crack; too low temperature will consume more processing energy and reduce the operating speed. Therefore, 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.
3. Hydraulic oil quality
One of the important properties of hydraulic oil is its chemical stability, that is, 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. Therefore, it is necessary to use suitable hydraulic oil and regularly check the oxidation degree of 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.
4. Oil filter cleaning
The oil filter plays a role in cleaning the hydraulic oil, so the oil filter should be cleaned every three months to keep the oil suction pipe unblocked, and at the same time check whether the oil filter screen is damaged.
5. Cooler cleaning
The cooler should be cleaned once a year, or according to whether its working capacity is reduced. Blockage or fouling inside the cooler will affect the cooling efficiency. The cooling water should be soft (mineral-free).Causes and solutions of common failures:
1. The cooling system is abnormal
1) Insufficient cooling system supply, for example, the water switch is not fully opened, the water pressure is insufficient, or the flow of the water pump does not meet the requirements, etc. 2) The pipeline is blocked, such as the filter screen, the cooling tower or the water pipe.
3) The cooling water temperature is too high, such as the cooling tower has insufficient heat dissipation capacity, or is damaged or the temperature is too high.
2. The hydraulic system generates high heat
1) The oil pump is damaged, and the internal parts are worn at high speed to generate high heat.
2) The pressure is not adjusted properly, and the hydraulic system has been under high pressure for a long time and overheated.
3) Internal leakage of hydraulic components, such as damage to the directional valve or damage to the sealing ring, causes heat to be generated when high-pressure oil flows through a small space.
3. Noise generation: Abnormal noise generation means that there are parts damaged or improperly adjusted, and the cause should be found out and repaired immediately according to the location of the noise.
1). Insufficient hydraulic oil in the oil tank, suction of air by the oil pump or obstruction of the oil filter will cause the oil pump to be short of oil, causing the air bubbles in the oil to discharge and hit the blades and generate noise. The solution is to check the oil volume to prevent air intake And clean the oil filter.
2) The hydraulic oil has high viscosity and increases the flow resistance, so it needs to be replaced with a suitable hydraulic oil.
3). Due to the damage of the bearings or blades of the oil pump or the motor, the concentricity deviation of the coupling causes noise, and the concentricity must be adjusted or the parts must be replaced.
4) The directional valve has failed response but still has its function, such as valve core wear, internal leakage, burr blockage, inflexible movement, and solenoid valve failure due to insufficient current will also cause noise. The solution is to clean the spool. If the spool is worn out, new parts must be replaced, and the current must be stable and sufficient.
5). The damage of hydraulic components or the blockage of the oil pipeline causes noise when the hydraulic oil flows at a high speed.
6). Mechanical part failure, bearing wear or mechanical lack of lubricating oil or parts loose, the reasons should be found to tighten or replace the parts to ensure that there is enough lubricating oil.
The so-called preventive maintenance is a series of preventive work and inspections to prevent machine failures and extend the working life of various parts. For example, the sudden occurrence of failures that cause production shutdowns can be turned into foreseeable and planned shutdown repairs or overhauls; it can be timely Discovery and replacement of damaged parts can prevent chain damage, etc., which are the purpose of preventive maintenance.