Selection and replacement technology of (a) vertical injection molding machine hydraulic oil

Date：2014/7/21 16:39:36

Vertical injection molding machine hydraulic system of hydraulic oil is an important medium of energy transfer, lubrication and cooling. Its main role is to transfer vertical injection molding machine hydraulic system of a point force applied to other parts. It also has a lubricating, cooling and rust and so on. The reliability of the hydraulic system operation, accuracy and flexibility, in addition to the design, material and performance depend on the equipment hydraulic components, but to a great extent dependent on the choice of vertical injection molding machine hydraulic oil and replacement techniques. Vertical injection molding machine injection molding process, temperature, pressure, flow and other process parameters need to be controlled according to the molding requirements to ensure product quality.
         To meet the pressure and flow rate can be precise, stable and continuously adjusted according to process requirements, must be prepared to maintain and repair the hydraulic system. Stability, reliability, reproducibility, sensitivity, energy efficiency and low noise performance injection molding machine hydraulic systems working directly affect the quality of injection products, dimensional accuracy, cycle time, production costs, work environment, safe operation and maintenance overhaul. Where the correct selection and replacement of hydraulic oil plays an important role. The author based on years of theoretical knowledge and practical experience were summarized.
         Category 1 vertical injection molding machine hydraulic oil in accordance with international regulations, hydraulic oil belongs to class L (Lubricants and related products) in group H (hydraulic systems), and to adopt a unified approach to naming its general form is: class - species numbers, for example, L-HM 68, L for the category (lubricants and related products); HM as varieties (with abrasion resistance, general hydraulic systems for high load); 68 for the grade (viscosity grade).
         Correct selection of two vertical injection molding machine hydraulic oil
         2.1 Select the vertical injection molding machine hydraulic oil requirement is no general principle of water, no mechanical impurities, corrosion and rust qualified, good anti-foam, suitable viscosity, and good abrasion resistance.
         Select the vertical injection molding machine hydraulic oil requirements are:
         (1) have the right viscosity, viscosity variation with temperature is smaller.
         Viscosity is an important property of a vertical injection molding machine hydraulic oil, under the same working pressure, the higher the viscosity, the slower the velocity of the various components, while the temperature quickly, the pressure drop and power loss. Control and regulation of low viscosity hydraulic oil hydraulic system will completely offset. Due to its different geographical and seasonal changes in system temperature difference before and after the start, will change the viscosity of the hydraulic oil, the oil viscosity is required to be small variation with temperature. A hydraulic system can only use a limited range of a certain viscosity or viscosity hydraulic oil change can play a greater efficiency. The hydraulic pump is one of the most sensitive to changes in viscosity of the oil component. Generally, other components of the system should be vertical injection molding machine according to the viscosity required to pump design and selection of the fluid viscosity. Injection molding machine temperature is higher, the larger the system pressure, and therefore to choose a slightly higher viscosity of the hydraulic oil.
         (2) have good lubricating properties.
         In recent years, the development trend of vertical injection molding machine hydraulic systems and components for high-power, small size, light weight and high-pressure, high-speed, high-volume, its purpose is to improve the efficiency of the hydraulic system. However, under such conditions, the oil pump and the motor, the control slide valve and the cylinder portion of such centers, in many boundary lubrication state. Boundary lubrication produce is often due to excessive load, or by other factors and the thickness of the lubricant film caused a decrease. In this case, a partial surface of a sintered friction occurs. Therefore, in order to prevent all kinds of wear, abrasion, fatigue stripped, requiring vertical injection molding machine hydraulic oil with good lubricating properties.
         (3) better oxidation resistance.
         Vertical injection molding machine hydraulic equipment at work, vertical injection molding machine hydraulic oil in contact with air, the role of oxygen in the air, hydraulic oil will oxidize, deteriorate, especially at high temperature and pressure conditions of oxidative faster oxidation The results generally showed darker, acid increases, the viscosity changes or produce a precipitate. Will enhance an increase in acid resistance, and a viscous liquid or a solid product produced by oxidation of high molecular weight, poor solubility. The polymer precipitate in suspension, may spread to various parts of the hydraulic system, causes filter blockage, vertical injection molding machine hydraulic pumps and other components wear, reduced efficiency, prevent operation of the control mechanism. Therefore, the requirements of the hydraulic oil is better oxidation resistance.
         (4) Shear Cean qualitatively better.
         Vertical injection molding machine when the hydraulic oil through the pump, valves, and other porous member is subjected to intense shearing action, which may cause mechanical action in the form of two kinds of change in viscosity, i.e., at high shear rate viscosity of temporary permanent viscosity loss and polymeric thickener molecules damage caused by the decline, and when the hydraulic oil viscosity drops to a certain limit, you can not continue to use, need to be replaced. Therefore, the requirements of the hydraulic oil shear Cean qualitatively better.
         (5) better corrosion resistance.
         Vertical injection molding machine hydraulic oil to prevent metal corrosion performance is good or bad, affect the service life of hydraulic components is very large.
         (6) Demulsibility better.
         Vertical injection molding machine hydraulic oil in the course of their work from different sources may be mixed with water, hydraulic oil, water can cause metal corrosion. Mixed with water under vigorous agitation in the hydraulic oil system regulator, pumps and other components, it is easy to form an emulsion. Particularly emulsion containing dust and other dirt, hydraulic oil may cause deterioration, degradation, and generation of sludge precipitate impede thermal cooler, block pipelines and valves, reduced hydraulic oil lubrication.
         (7) anti-foaming better.
         In the vertical injection molding machine hydraulic circulation system, hydraulic oil containing bubbles will affect the compression ratio of the hydraulic fluid, and finally to the energy transfer instability. Furthermore, the presence of bubbles also increases the contact area with the air hydraulic oil, hydraulic oil accelerated oxidation. When a large amount of air dissolved by high-pressure liquid cylinders, valves and other components work, most of the air is released to generate foam, and went back to the tank with oil, and then mixed with the hydraulic system, will produce power transmission lag, lost power delivery reliability and accuracy. Serious, oil will overflow tank, not the normal production.
         Cleanliness (8) oil is better.
         The reason a lot of hydraulic oil contamination, airborne dust, metal shavings, sand casting can become residual oil in the dirt. Dirty hydraulic oil that can clog filter pores less oil, cavitation, vibration and noise occur, but also the difficult operation of sliding portions, reliability and accuracy of the impact action, so that wear of sliding parts in an early stage.
         (9) on the sealing material to be small.
         Vertical injection molding machine hydraulic sealing materials used in the system, depending on the type of hydraulic oil varies, such as when used as a sealing material nitrile rubber hydraulic system should be selected mineral hydraulic oils, and use phosphate-based flame-resistant hydraulic oil will malfunction.
         Impact of vertical injection molding machine hydraulic oil on the sealing materials are: the sealing material to produce swelling and softening; hardening of the sealing material. The result is the loss of sealing performance of the sealing material, causing leakage and eventually the system pressure drop, out of control, that it can not work. Therefore, the impact of hydraulic oil required for the sealing material should be small, the sealing material to be used with the system to adapt.
         2.2 vertical injection molding machine hydraulic oil varieties selection
         According to the principle of vertical injection molding machine to select and use characteristics of hydraulic oil injection molding machine, lubricant requirements are: a viscosity index of 90 or more; 40 e kinematic viscosity of 32 mm2 / s or more; N46, N68, etc.; should not use the foaming of pressure oil. Disable different types of different grades of oil. Optional containing anti-wear agent, anti-oxidants, anti-corrosion additives in oil.

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