Comparative Study of the Shear Strength of Plastic Sheet Joined by Laser Transmission Welding (LTW)
Y-T. Cheng, Y-W. Wang, Z. Liu, Y-M. Wang And Y-J. Cao
Poly(methyl methacrylate) (PMMA) transparent sheet and polystyrene semitransparent sheet were joined together by laser transmission welding (LTW). Thereafter the shear strength of the resultant samples was examined by two methods: single-lap method without additional joint and single-lap method with additional joint. The comparative testing results show that single-lap joint method without additional joint could not keep the stress at vertical definition to the sheet surface during testing, and the single-lap method with additional joint also failed in shielding the specimens from tensile stress during testing, due to the existence of additional bending moments. It implies that the additional lap joint at the fixture block is not successful in providing pure shearing stress condition for the sheet.
Keywords: Diode laser, poly(methyl methacrylate) (PMMA), polystyrene, laser transmission welding (LTW), shear strength, weld quality, single-lap joint