The moving parts with different thermal expansion coefficients in the hydraulic components are stuck due to their smaller fitting clearances, causing action failure, affecting the transmission accuracy of the hydraulic system, and resulting in poor working quality of the components.
Hazard two: reduce the viscosity of the oil
The excessive temperature rise of the injection molding machine will result in a decrease in the viscosity of the oil, an increase in leakage, and a significant decrease in the volumetric efficiency of the pump and the efficiency of the entire system. As the viscosity of the oil decreases, the oil film of the moving parts such as the spool valve is thinned and cut, and the frictional resistance increases, resulting in increased wear.
Hazard 3: Deformation of rubber seals
The excessive temperature rise of the injection molding machine will deform the rubber seal, accelerate the aging failure, reduce the sealing performance and service life, and cause leakage.
Hazard 4: Accelerate the oxidative deterioration of oil
If the temperature rise of the injection molding machine is too high, it will accelerate the oxidation and deterioration of the oil, precipitate asphalt substances, and reduce the service life of the hydraulic oil. Precipitates block the damping holes and slit valve ports, causing the pressure valve to be stuck and unable to operate, the metal pipeline to stretch and bend, or even rupture.
Hazard five: lead to poor work quality of components
If the temperature rise of the injection molding machine is too high, the working quality of the components will deteriorate, the dissolved air in the oil will escape, and air pockets will be generated, which will reduce the working performance of the hydraulic system. The ideal working temperature of the hydraulic system should be between 45 degrees and 50 degrees. 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, etc., reduce the control accuracy and response sensitivity, especially for precision injection machines. At the same time, if the temperature is too high, the aging of the seal will be accelerated, causing it to harden and crack; if the temperature is too low, the processing energy will be consumed and the operating speed will be reduced. Therefore, it is necessary to pay close attention to the working temperature of the hydraulic oil. There are various reasons for the high oil temperature, but most of them are due to oil circuit failure or cooling system failure.
The injection molding machine temperature is a too high treatment method
(1) According to different load requirements, check and adjust the pressure of the relief valve frequently to make it just right.
(2) Reasonable selection of hydraulic oil, especially oil viscosity, when conditions permit, try to use a lower viscosity to reduce viscosity friction loss.
(3) Improve the lubrication conditions of moving parts to reduce friction loss, which is conducive to reducing workload and heat generation.
(4) Improve the assembly quality and precision of hydraulic components and hydraulic systems, strictly control the matching clearance of matching parts and improve lubrication conditions. The sealing material with a small friction coefficient and the improved sealing structure is used to reduce the starting force of the hydraulic cylinder as much as possible to reduce the heat generated by the mechanical friction loss.
(5) Add a cooling device if necessary.