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Causes And Treatment Of Excessive Temperature Rise In Hydraulic System Of Injection Molding Machine

2008/8/11 9:50:00 41797

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1 damage caused by excessive temperature rise of injection molding machine

(1) make the machine produce hot deformation, and the moving parts with different thermal expansion coefficients in the hydraulic components are jammed because of their smaller clearance, causing the movement to malfunction and affecting the pmission accuracy of the hydraulic system, resulting in the poor working quality of the components.

(2) reduce the viscosity of the oil and increase the leakage. The volumetric efficiency of the pump and the efficiency of the whole system will be significantly reduced.

As the viscosity of the oil decreases, the oil film of the moving parts of the slide valve is thinned and cut, and the frictional resistance increases, resulting in the aggravation of the wear.

(3) make the rubber seal deform, accelerate the aging failure, reduce the sealing performance and service life, and cause leakage.

(4) accelerating the oxidation and deterioration of the oil, and separating the asphaltene material, and reducing the service life of the hydraulic oil.

The precipitates plug the damping orifice and the slit type valve port, resulting in the pressure valve being stuck and unable to act, the metal pipeline elongated, bent or even cracked.

(5) reducing the air separation pressure of the oil, escaping the dissolved air in the oil, resulting in cavitation, resulting in a decrease in the performance of the hydraulic system.

2 reasons for excessive temperature rise of injection molding machine

(1) the volume of the tank is too small, the heat dissipation area is not enough, and the cooling device is too small.

(2) the quantitative pump oil supply system that selects the oil pump capacity according to the fast forward speed will have most of the excess flow at the working stage and overflow from the overflow valve under high pressure and heat.

(3) failure of the unloading circuit in the system or failure to set up the unloading loop, when the pump is stopped, the oil pump can not be unloaded. All the flow of the pump will overflow under high pressure, causing overflow loss and heating, leading to temperature rise.

(4) the pipeline system is too long, too much bent, partial pressure loss and large pressure loss along the path.

(5) the accuracy of components is not enough and the quality of assembly is poor.

(6) the fit clearance of the mating parts is too small, or if the clearance is too large after wearing, the volume of leakage inside and outside is large, resulting in the volume loss, such as the volume efficiency of the pump is reduced, and the temperature rise is fast.

(7) the working pressure of the hydraulic system is much higher than that of actual demand.

Sometimes it is because the seal is too tight, or because the seal is damaged and the leakage is increased, the pressure must be raised to work.

(8) high temperature in the climate and operating environment leads to higher oil temperature.

(9) the viscosity of the selected oil is improper, the viscosity is large, the viscous resistance is large, the viscosity is too small, the leakage increases, and the two conditions can cause the heating temperature rise.

3 injection molding machine temperature rise too high processing method

(1) according to different load requirements, check and adjust the pressure of the relief valve regularly to make it right.

(2) reasonable selection of hydraulic oil, especially the viscosity of oil, should be used as low as possible to reduce viscosity and friction loss if conditions permit.

(3) improve the lubrication condition of the moving parts to reduce the friction loss, reduce the work load and reduce the fever.

(4) improve the assembly quality and accuracy of hydraulic components and hydraulic systems, strictly control the fit clearance and improve the lubrication conditions.

The sealing materials with small friction coefficient and improved sealing structure are adopted to reduce the starting force of the hydraulic cylinder as far as possible, so as to reduce the heat generated by the mechanical friction loss.

(5) cooling devices should be added if necessary.