Because there are many types of hydraulic pumps in injection molding equipment, the same type of pumps are affected by factors such as power, speed, pressure, flow, and metal materials, making the selection of hydraulic oil more complicated. Generally speaking, HL oil can be used for low-pressure pumps, and HM oil should be used for medium and high-pressure pumps.
The lubricity (anti-wear) of hydraulic oil has the effect of vane pump>plunger pump>gear pump on the anti-wear effect of the three major pumps. Regardless of the pressure, the vane pump should choose HM oil for the hydraulic system of the main oil pump, because the contact and movement between the vane and the stator of the vane pump are very easy to wear, and the steel-to-steel friction pair material is most suitable for the use of high zinc HM anti-wear hydraulic oil.
For low-pressure plunger pumps, HM oil and HL oil can be used, and for high-pressure plunger pumps, zinc-containing HM oil is used. However, when there are bronze and silver-plated parts in the plunger pump, the high-zinc antiwear agent will cause corrosion and wear. This kind of plunger pump Choose ash-free or low-zinc anti-wear hydraulic oil.
For gear pumps, HH, HL, HM oil can be used, but high-performance gear pumps should use HM oil. For combined systems such as vane pumps and other pump combinations, the vane pump should be the main choice. When the other pumps are plunger pumps, the selected oil should also be accepted by the plunger pump.
In general, HL oil can be preferentially used for axial piston pumps, but not for vane pumps. High zinc HM oil is suitable for all types of vane pumps. Ash-free HM oil is suitable for axial piston pumps containing copper and silver components, as well as for medium and low pressure vane pumps, but not for high pressure vane pumps. Low-zinc HM oil has a wide range of applications, not only for medium and high-pressure vane pumps, but also for plunger pumps with copper and copper components.
Reasonable selection of hydraulic fluid is only the starting point for the normal operation of hydraulic equipment. During system operation, the performance changes of hydraulic fluid should be detected in time to ensure timely and appropriate maintenance to extend the service life of hydraulic fluid, systems and components. Avoid system failures and even accidents caused by working media.
The service life of hydraulic oil (i.e. oil change period) varies greatly depending on the type of hydraulic oil, the working environment and the operating conditions of the system. The selected oil is reasonable and the quality of the oil is excellent. With good maintenance and management, the oil change period can be greatly extended.