The working principle of the injection molding machine
Injection molding machines are the core equipment for plastic molding. Their working process involves mold clamping, injection of plastic, pressure retention, cooling, and mold opening. The core transmission and guiding components are constantly under high load, low-speed reciprocating, and high-frequency oscillation conditions, and key parts often have lubrication problems. Self-lubricating bronze bushings (self-lubricating sleeve series) have unique properties and have become the core matching components for critical guidance and joint systems in this field, precisely solving the problems of lubrication and wear resistance.
I. Core operating conditions of injection molding machines: The main driving force behind the need for self-lubrication
The molding accuracy and operational stability of injection molding machines rely on the precise coordination of all moving parts. Their working conditions have revealed the limitations of traditional lubrication methods, which has also led to the demand for rigid self-lubricating sleeves.
High load: The pressure resistance strength of the components is extremely high.
1.During the mold closing stage, the mold locking mechanism of the injection molding machine needs to generate hundreds to thousands of tons of locking force to close the mold and prevent the melted resin from overflowing. In the injection stage, the injection cylinder pushes the screw to inject the resin at pressures ranging from tens to hundreds of megapascals. These pressures are transmitted to components such as the guide sleeve, hinge connection head, and pull rod slider, causing them to bear extreme loads. The dense bronze matrix of the self-lubricating sleeve has an appropriate hardness, which can effectively distribute the load, prevent deformation and fracture, and provide reliable load-bearing support.
2. Low-speed oscillation: Increased risk of friction and wear
The mold closing, opening and ejection processes of the injection molding machine are all low-speed reciprocating motions (with a speed of 0.1 - 0.5 m/s), accompanied by high-frequency oscillations. The hinge connection joints, guide columns and guide sleeves and other parts need to repeatedly change the direction of movement, resulting in intermittent friction. Traditional rolling bearings are prone to jamming and accelerated wear, while the graphite/PTFE/MoS₂ lubrication layer of the self-lubricating sleeve can form a stable oil film, reducing friction and wear, and avoiding the impact on the molding efficiency caused by jamming.
3. Limited lubrication: Traditional lubrication methods are completely impractical.
The key guiding and connection systems of injection molding machines are mostly of closed or semi-closed structure. They are closely adjacent to the high-temperature cavities and are prone to accumulate plastic debris and dust. Traditional grease or drip oil lubrication is difficult to continuously replenish the grease and is also prone to form oil sludge that blocks the gaps and contaminates the molds and products. In food-grade and medical-grade molding scenarios, the use of lubricants is even more prohibited to prevent contamination. This further limits the application of traditional lubrication.
II. Self-lubricating Sleeve Series: The Ideal Fit for Key Parts of Injection Molding Machines
In response to the operational challenges of injection molding machines, the self-lubricating sleeve series features the core advantages of "no need for continuous lubrication, wear-resistant and capable of withstanding heavy loads, and suitable for harsh environments". It is widely used in various critical guidance and connection systems and is a key component for ensuring the stable operation of the equipment.
Specifically, it can be adapted to the hinge connection head of the locking mechanism, the pull rod guide sleeve, the screw support sleeve of the injection mechanism, the guiding part of the injection cylinder, as well as the push rod guide sleeve of the ejecting mechanism and the slider guide rail, etc. These parts need to take into account high load, low-speed oscillation, no oil contamination, and maintenance-free requirements. The bronze base of the self-lubricating sleeve ensures the load-bearing capacity, the lubrication layer achieves oil-free lubrication, and the precise process ensures compatibility, which can extend the component lifespan, reduce downtime maintenance, and improve efficiency.
Compared with ordinary bushings or rolling bearings, the self-lubricating sleeve series is more suitable for the working conditions of injection molding machines. It can withstand high loads and low-speed oscillating environments, completely solving the problem of continuous lubrication at key parts, providing a guarantee for the stable operation and precise molding of the equipment, and is an indispensable core component in the injection molding machine industry.