Reasons for the cracking of the barrel screw kneading r […]
Reasons for the cracking of the barrel screw kneading roller:
1. The reason for the fracture of mechanical parts materials (barrels, screws, kneading blocks) is nothing more than the reduction of the original size of the parts after wear; material congenital defects, such as congenital cracks, looseness, segregation, brittleness, etc.; parts Insufficient estimation of the working torque during design; insufficient heat treatment of materials (usually referred to as quenching and tempering treatment), fatigue of materials after long-term use, etc.
2. All mechanical parts (barrels, screws, kneading blocks) cracked during use should be analyzed item by item and eliminated item by item according to the above reasons;
3. Plastic machinery parts (barrel, screw, kneading roller), especially the kneading roller this time, when the working conditions are high torque and high wear, the requirements for materials are particularly high. Theoretically, we must use special steel to manufacture, these steels must have high density (for example, after secondary forging), high hardness, high wear resistance, high compressive strength, high fatigue strength, high thermal stability, and excellent impact toughness And excellent ductility, etc.;
4. After using the above-mentioned high-density, high-strength special high-alloy steel that may have undergone secondary forging, the material must undergo non-destructive testing before entering the factory. There are two types of non-destructive testing: magnetic particle testing and ultrasonic testing. After flaw detection, no cracks or loose materials are found before entering the manufacturing process.