Screw Force Situation

1) Self weight G; 2) The torque M required to overcome material resistance; 3) The axial force P generated by material pressure.
Screws are generally scrapped due to long-term wear and tear, and the gap between the screw and the material barrel is too large to be extruded normally. However, there are also examples of damage caused by improper design or operation, where the working stress exceeds the strength limit. Therefore, screws should also meet certain strength requirements. 4) The dangerous section of the screw is generally located at the minimum root diameter of the thread in the feeding section. According to material mechanics, for plastic materials, the composite stress is calculated using the third strength theory, and its strength conditions are: