The classification of wear types mainly includes the following points:
Features:
It is regional and usually occurs in locations that produce high mechanical stress.
The degree of wear is closely related to the hardness, shape and size of the abrasive, and sharp and hard abrasive particles tend to cause more severe wear.
The rate of wear may increase with the increase in material flow because more abrasive particles are involved in the friction process.
Affected by the operating temperature of the extruder, high temperatures may lead to a reduction in the hardness of the metal surface, which will aggravate abrasive wear.
Features: Worn parts have smooth, rounded edges and edges.
Diagnosis:
Judge the area of wear: generally can be judged in the feeding, melting, mixing, exhaust, pressure building area and other areas.
Check the material for impurity particles with high hardness.
Analyze the operating parameters of the extruder, such as speed, pressure, etc., to observe whether there is an abnormal increase in mechanical stress.
Monitor the operating temperature to see if there is a high temperature beyond the normal range.
Countermeasure:
Replace parts promptly. It can be regularly maintained, and at the same time, it is also necessary to replace some parts of the parts with serious wear in time to avoid the phenomenon of wear passing to the downstream.
According to the degree of wear, more suitable wear accessories can be selected. Wear-resistant threaded components and barrels can be selected according to the formula and process.
Features:
It is regional and occurs in the area where chemical reactions occur on the surface of corrosive materials and metal parts.
The rate of corrosive wear usually increases with the increasing concentration of corrosive materials.
Changes in ambient humidity may affect the rate of corrosion reaction, and corrosion wear tends to be more serious when humidity is higher.
The increase in temperature may accelerate the chemical reaction, which in turn increases the degree of corrosion wear.
Features: The surface of the accessories is relatively rough, with a bit of corrosion, holes and honeycomb surface conditions.
Diagnosis:
Determine where corrosive materials or additives are added and observe the condition of the parts in the area.
Test the pH and corrosive content of the material.
Check the protective coating or coating for breakage or peeling.
Countermeasure: It must be solved by selecting corrosion-resistant accessories, according to the corrosive medium, select suitable corrosion-resistant accessories.
Features:
It mainly occurs in some areas where metal parts rub against each other.
The severity of internal wear is related to the operating speed of the equipment. The higher the speed, the higher the friction frequency, and the more serious the wear may be.
The load change of the equipment also affects the internal wear and tear. When the load is unstable or suddenly increases, the wear may be aggravated.
Internal wear may also cause heating of parts, further affecting their mechanical properties and service life.
Features: The top of the threaded element has scratches, and there are curly edges on both sides. The side of the spiral edge has scratch marks, and the inner wall of the barrel also has scratch marks.
Diagnosis:
Whether the screw combination is unreasonable, the material filling is insufficient when it works, resulting in insufficient support and lubrication of the screw.
When the screw is assembled, its phase is wrong or the screw is distorted, resulting in interference when the part is rotating.
Axial movement occurs when the screw and coupling are assembled.
There are steps and misalignment when the barrel is assembled.
Detect the operating speed and load changes of the equipment.
Check the working status of the lubrication system to see whether the lubricating oil is sufficient and the quality is qualified.
Countermeasures: First of all, you can adjust the screw combination and choose some high-quality parts manufacturers. At the same time, it is also necessary to ensure the accuracy of accessories and assembly accuracy, and strengthen the training of equipment maintenance personnel, and carry out regular maintenance work.
