Surface Microstructure Regulation via Femtosecond Laser for Enhancing Laser Welding Strength of PVC/PA66: Mechanisms...

Area of Science:

• Materials Science
• Polymer Science
• Laser Processing

Background:

• Laser welding of dissimilar polymers like polyvinyl chloride (PVC) and polyamide 66 (PA66) is hindered by weak interfacial bonding.
• Achieving sufficient joint strength for engineering applications remains a significant challenge.

Purpose of the Study:

• To propose and investigate a welding reinforcement strategy using femtosecond laser surface microstructuring.
• To enhance the interfacial bonding and joint strength in laser-welded incompatible polymer systems.

Main Methods:

• Fabrication of high-precision microgroove structures on PVC surfaces using femtosecond laser.
• Systematic investigation of groove parameters (width, depth, spacing, configuration) on welding performance.
• Fracture morphology characterization and finite element simulation to reveal reinforcement mechanisms.

Main Results:

• Optimal process parameters (70 μm width, 70 μm depth, 130 μm spacing) yielded a maximum shear strength of 15.4 MPa with vertical groove structures.
• Vertical grooves provide superior unidirectional load-bearing strength.
• Grid grooves effectively mitigate stress concentration under multidirectional loading.

Conclusions:

• Femtosecond laser surface microstructuring offers a high-precision, versatile method for welding incompatible polymers.
• Microgroove-induced mechanical interlocking significantly improves laser weld strength.
• This approach provides a valuable theoretical reference for dissimilar polymer laser welding optimization and applications.