Injection moulding machine is pivotal in manufacturing high-precision plastic components across various industries. One crucial aspect of their operation is effective lubrication, which ensures smooth functioning, reduces wear and tear, and extends the lifespan of the machinery. Among the critical components facilitating this process is the lubrication distributor. In this blog, we’ll explore its working principles, types, advantages, and maintenance tips.
Principle and type
1. Impedance type
The working principle of the impedance-type distributor is to set a small channel on the pipeline to increase the resistance. It can only distribute the flow proportionally and is greatly affected by the pressure of the lubricant at the front and rear ends of the distributor. It is the most straightforward and most economical distributor.
The so-called spiral impedance type is to insert a core rod (shaped like a screw) with a small gap on the surface of the spiral groove into the standard hole (the accuracy can be processed to H7 to H6 level). Controlling the depth and length of the spiral groove controls the size of the damping; the so-called small hole annular gap impedance type is to put a core rod with a smaller diameter in the standard hole. There is an annular gap between the hole and the core rod. The size of the annular gap is adjusted by controlling the size of the core rod diameter.
Similarly, the small hole and the core rod cannot be processed too long, so the annular gap can only be controlled to be smaller, so it is also easy to get blocked. Impedance-type distributors are widely used on Injection moulding machine because of their compact structure, economy, convenient operation and maintenance, and freedom to increase and decrease lubrication points.
2. Volumetric type
Based on their working principle, volumetric distributors are divided into pressurized volumetric type and depressurized volumetric type. The so-called pressurized volumetric type means that the pressure oil delivered by the lubricating pump pushes the piston in the metering part, forcibly pressing the lubricant stored in the metering chamber last time to the lubrication point. When the lubricating pump stops supplying oil and relieves pressure, the piston resets under the action of the spring force and is ready for the next oil supply.
The pressure-relief volumetric type lubrication system operates by storing oil in the metering piston under the pressure of the lubricating pump. When the pump stops supplying oil and pressure is relieved, the spring force pushes the piston to discharge the stored oil. This design allows the system to supply oil to lubrication points at high pressure, ensuring reliable performance.
However, the working principle reveals certain limitations. The volumetric distributor discharges oil only once per cycle of pump operation, stopping, and unloading. During unloading, the spring resets slowly, demanding high pressure relief in the main line. This results in lower “working efficiency,” particularly during initial testing of plastic injection machines, where some components require significant oil volumes, leading to longer refueling times.
Additionally, the inclusion of rubber, springs, and other components in the distributor affects its reliability and pressure resistance, posing durability concerns. Despite these drawbacks, volumetric distributors are favored in small to medium-sized Injection moulding machine for their precise and reliable lubrication, ease of system pressure detection, and convenient management of lubrication points. However, their relatively higher cost compared to impedance distributors limits their widespread use.
3. Progressive distributors
The basic working principle of the distributor is to use hydraulic progressive action. It means that each working plunger pair in the distributor, after following the cyclic action of the previous working plunger pair, works to complete its plunger stroke and delivers a certain amount of lubricant to the lubrication point.
As long as the pressurized lubricant is supplied to the distributor, the working plunger pair will operate progressively and inject oil at a constant displacement. Then, once the flow of the supplied pressurized lubricant stops, the distributor’s working plunger will also stop moving. When the pressurized lubricant starts to flow again, the working plunger in the distributor starts its oil injection cycle at the same point again.
Progressive distributors are structurally divided into two types: integrated and chip types. The integrated distributor is a whole valve body with a compact structure and convenient installation. However, the valve body is generally made of aluminum alloy, and the threaded port is easily damaged. Moreover, the gap between the working plunger and the valve body will increase at abnormally high pressure, resulting in leakage, and the progressive action will continue incorrectly. In addition, the integrated distributor has the same displacement per hole, which makes it challenging to adapt to the various oil requirements of the injection moulding machine.
Usage
1. Preparation:
Before using the hydraulic plastic moulding machine lubrication distributor, preparation is required. First, it is necessary to check whether the lubrication system of the injection moulding machine equipment is standard, including whether the lubricating oil in the system is sufficient, whether there is oil leakage in the oil pipe, etc. Secondly, the lubrication distributor needs to be installed and debugged.
2. Install the lubrication distributor:
The lubrication distributor is installed on the pipeline of the lubrication system of the automatic plastic moulding machine equipment and needs to be connected to the pipeline. After the connection, the corresponding tightening and sealing work is performed.
3. Adjust the lubrication distributor:
The adjustment of the lubrication distributor needs to be carried out according to the lubrication requirements of the specific injection moulding machine equipment. The specific operation is first to check whether the operation of the single screw pump is regular and adjust the opening of the pump outlet valve until the amount of lubricating oil discharged meets the requirements. Then, adjust the oil pipe interface of the lubrication points of each part to ensure that the lubricating oil reaches each part.
4. Check the use effect:
After using the lubrication distributor, the automatic injection molding machine equipment needs to be checked to ensure that the lubrication effect meets the requirements. If any problems occur, timely processing and maintenance are required.
Function
The injection moulding machine lubricating oil progressive distributor needs to ensure that each part that needs lubrication can be adequately lubricated during the operation of the machine so as to reduce the wear of the machine parts effectively, extend the service life of the injection moulding machine, and improve the working efficiency of the injection machine. At the same time, the injection moulding machine lubricating oil progressive distributor can also ensure the amount of lubricating oil used and the degree of waste. Suppose the lubricating oil is used too much. In that case, it will cause unnecessary waste and environmental pollution. If it is not used enough, it will shorten the life of the injection moulding machine and reduce its working efficiency.
Summary
In short, the injection moulding machine lubrication distributor can effectively improve the working efficiency and life of the injection molding machine equipment. When using it, you need to pay attention to the preparation work, correctly install and adjust the lubrication distributor, and finally check the use effect.
FAQ
Specialized lubricants like high-performance synthetic greases or oils designed for high temperatures and heavy loads are commonly used to reduce wear and ensure smooth operation in plastic injection molding.
Hydraulic oils such as ISO VG 46 or ISO VG 68 are typically used in injection molding machines for smooth operation and effective heat dissipation.
Connect the distributor to the lubrication system, ensure proper calibration, and monitor the flow to evenly distribute lubricant to all critical machine components.
