One of the hazards: causing thermal deformation of the machinery
The moving parts with different thermal expansion coefficients in hydraulic components become stuck due to the smaller fitting clearance, causing movement failure, affecting the transmission accuracy of the hydraulic system, and resulting in poor working quality of the components.
Hazard 2: Reduce the viscosity of the oil
Excessive temperature rise of the injection molding machine will cause the viscosity of the oil to decrease, leakage to increase, and the volumetric efficiency of the pump and the efficiency of the entire system to be significantly reduced. As the viscosity of the oil decreases, the oil film on moving parts such as slide valves becomes thinner and cut, and frictional resistance increases, leading to increased wear.
Hazard No. 3: Deformation of rubber seals
Excessive temperature rise of the injection molding machine will deform the rubber seal, accelerate aging and failure, reduce sealing performance and service life, and cause leakage.
Hazard No. 4: Accelerated oxidation and deterioration of oil
Excessive temperature rise of the injection molding machine will accelerate the oxidation and deterioration of the oil, precipitate asphalt substances, and reduce the service life of the hydraulic oil. The precipitates block the damping holes and slot valve ports, causing the pressure valve to become stuck and unable to operate, the metal pipeline to stretch and bend, or even rupture.
Hazard No. 5: Leading to poor quality of components
If the temperature of the injection molding machine rises too high, the working quality of the components will deteriorate, and the dissolved air in the oil will escape, causing air pockets, which will reduce the working performance of the hydraulic system. The ideal operating temperature of the hydraulic system should be between 45 degrees and 50 degrees. The reason is that the hydraulic system is designed based on 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, if the temperature is too high, it will also 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 be reduced. Therefore it is necessary to pay close attention to the operating temperature of hydraulic oil. There are many reasons for excessive oil temperature, but they are mostly attributed to oil line failure or cooling system failure.
How to deal with excessive temperature of injection molding machine
(1) According to different load requirements, frequently check and adjust the pressure of the relief valve to make it just right.
(2) Reasonably select the hydraulic oil, especially the oil viscosity. If conditions permit, try to use a lower viscosity to reduce viscosity friction loss.
(3) Improve the lubrication conditions of moving parts to reduce friction losses, which is beneficial to reducing workload and heat generation.
(4) Improve the assembly quality and accuracy of hydraulic components and hydraulic systems, strictly control the fitting clearance of mating parts and improve lubrication conditions. Use sealing materials with small friction coefficients and improved sealing structures to reduce the starting force of the hydraulic cylinder as much as possible to reduce the heat generated by mechanical friction loss.
(5) Add a cooling device if necessary.
