Influence of high temperature of injection molding machine and its solution
There are five major hazards to the high temperature rise of the injection molding machine: it will cause thermal deformation of the machine, reduce the viscosity of the oil, deform the rubber seal, accelerate the oxidative deterioration of the oil, and also reduce the component pressure of air.
One of the hazards: thermal deformation of the machine
The moving parts with different thermal expansion coefficients in the hydraulic components are stuck because their mating clearances become smaller, causing action failures, affecting the transmission accuracy of the hydraulic system, and resulting in poor working quality of the parts.
Hazard 2: Reduce the viscosity of the oil
If the temperature of the injection molding machine is too high, the viscosity of the oil will decrease, and the leakage will increase. The volumetric efficiency of the pump and the efficiency of the entire system will be significantly reduced. As the viscosity of the oil decreases, the oil film of moving parts such as slide valves becomes thinner and is cut, increasing frictional resistance, resulting in increased wear.
Hazard 3: Deformation of rubber seals
Excessive temperature rise of the injection molding machine will deform the rubber seals, accelerate aging failure, reduce sealing performance and service life, and cause leakage.
Harm 4: Accelerate the oxidative deterioration of oil
Excessive temperature rise of the injection molding machine will accelerate the oxidative deterioration of the oil, precipitate asphalt, and reduce the service life of the hydraulic oil. The precipitates plug the damping orifice and the slit valve port, causing the pressure valve to become stuck and unable to operate, the metal pipe extended and bent, or even cracked.
Fifth hazard: lead to poor working quality of components
Excessive temperature rise of the injection molding machine will cause the working quality of the components to deteriorate, and the dissolved air in the oil will escape, creating air pockets, 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 based on 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 and hydraulic valves, reduce control accuracy and response sensitivity, especially for precision injection machines. At the same time, too high temperature will also accelerate the aging of the seals, causing them to harden and crack. If the temperature is too low, the processing energy consumption will be large, which will reduce the operating speed. 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 they are mostly due to oil circuit failure or failure of the cooling system.
High temperature treatment of injection molding machine
(1) According to different load requirements, often check and adjust the pressure of the relief valve to make it just right.
(2) Reasonably select the hydraulic oil, especially the viscosity of the oil. When the conditions allow, use a lower viscosity as much as possible to reduce the viscosity friction loss.
(3) Improve the lubricating conditions of moving parts to reduce friction loss, which is conducive to reducing work load and reducing heat generation.
(4) Improve the assembly quality and accuracy of hydraulic components and hydraulic systems, strictly control the clearance of the mating parts and improve the lubrication conditions. The sealing material with small friction coefficient and improved sealing structure are used to reduce the starting force of the hydraulic cylinder as much as possible to reduce the heat generated by mechanical friction loss.
(5) Add cooling devices if necessary.