I. Ensure screw and pre-drilled hole match (core prerequisite)
Improper hole diameter design is the primary cause of stripping. The appropriate hole diameter must be selected based on the material thickness and type:
Hole diameter too large: Insufficient engagement between the screw threads and the substrate, easily leading to loosening and stripping;
Hole diameter too small: High tapping resistance, easily causing screw breakage or thread damage.
II. Optimize hole structure design
For thin sheet materials (<1.0mm), flanged holes should be preferred over flat holes. Flanged holes increase the effective engagement length of the material, significantly improving anti-stripping ability.
III. Use high-quality screws and eliminate structural defects
Inferior screws have several hidden dangers that easily lead to stripping:
Thread size and diameter do not meet standards;
Pitch deviation leads to insufficient "bite" depth;
Thread angle is too small (ideally 60°–65°), affecting the engagement force;
Incomplete threads or the presence of a reverse taper.
It is recommended to use high-strength self-tapping screws that meet national standards and to regularly check key dimensions.
IV. Standardized Installation Procedures
1. Tool Matching: Use a screwdriver bit that is perfectly matched to the screw slot type (e.g., PH2 Phillips head) to avoid uneven force caused by using a "universal bit".
2. Maintain Vertical Force: Ensure the screw axis is perpendicular to the mounting surface when screwing in. Tilt will cause overload wear on one side of the thread.
3. Control Tightening Torque:
Use a torque screwdriver or an adjustable torque electric screwdriver; set a reasonable torque value according to the screw specifications to avoid overtightening or undertightening.
4. Avoid Repeated Disassembly and Assembly: The effective assembly and disassembly times of self-tapping screws on plastic parts are generally no more than 8 times. Frequent disassembly and assembly will accelerate the failure of plastic threads.
V. Special Scenarios and Techniques
Plastic Part Installation: The "reverse pre-tightening" method can be used-first, gently tighten counterclockwise to feel the original thread positioning, then tighten clockwise to avoid secondary tapping that could damage the existing threads.
High vibration environment: Apply an appropriate amount of anti-loosening adhesive (such as Loctite 243) to the threads to enhance the locking force.
