1. Use of Anti-Loosening Screws or Nuts

• Self-Locking Nuts: These nuts prevent loosening by increasing friction or using mechanical locking mechanisms. For example, nylon-insert locking nuts or wedge-locking nuts use a wedge-shaped surface to increase normal pressure, significantly enhancing anti-loosening capabilities.
• Double Nuts: By tightening two nuts against each other, additional friction is created, preventing loosening.

2. Auxiliary Fixation Methods

• Threadlockers: Applying threadlockers, such as anaerobic adhesives, to the threads of self-tapping screws fills the thread gaps and creates a strong bond when the screw is tightened. This prevents loosening due to vibration.
• Spot Welding or Riveting: For screws that require high anti-loosening performance and are not frequently disassembled, spot welding or riveting can be used. Spot welding fuses the screw with the material, while riveting deforms the screw head to secure it.

3. Mechanical Anti-Loosening Methods

• Spring Washers: These washers generate continuous elastic force when flattened, maintaining friction between the nut and bolt to prevent loosening.
• Cotter Pins and Slotted Nuts: Inserting a cotter pin through the nut's groove and the bolt's end hole prevents relative rotation between the nut and bolt.
• Stop Washers: After tightening the nut, the stop washer's ears are bent to tightly adhere to the nut and connecting part, preventing the nut from rotating.

4. Process Control

• Precise Torque Control: Using torque-controlled tools ensures that the screws are tightened to the specified torque, preventing loosening due to insufficient or excessive tightening.
• Controlled Tightening Speed: Avoiding high-speed tightening reduces thermal effects, especially in plastic materials, which can damage the screw holes.

5. Other Measures

• Hot-Melt Fastening Technology: This method eliminates the need for pre-drilling and allows direct tapping into materials, creating a secure connection. It is widely used in industries like automotive.
• Preload Optimization: Ensuring sufficient preload force in high-strength bolt connections can prevent loosening by maintaining strong frictional forces between the nut and connected parts.