1. Comparing studies of LVW and OVW joining technologies demonstrated that the OVW process is very efficient for nylons and may be used as an alternative to LVW and ultrasonic (U/SW) technologies for welding of the small components. 2. For both frictional (LVW, OVW) and H-P joining technologies the maximum tensile strength at weld was achieved in materials with 14 to 24 wt.% GF. 3. Studies on heat-generation and melt propagation in weld area (time-temperature profile) in LVW processing using infrared technology (IR) have demonstrated the dynamic of temperature distribution in overall and interface areas. For joining of the similar nylons, a difference of 15 - 20℃ at the interface was found during the steady state in LVW technology and as a result the hot-plate / tool temperature (H-P technology) is recommended. The difference may be due to the accuracy of the previously applied measurement methods, the calibration procedures, and so on. The utilization of the standard IR method and Thermovision 900~(~R) Series System. (FSI / Agema) allows one to monitor the temperature distribution in overall and local (interface) areas. 4. The increased melt temperature (in interface) at welding time is well correlated with the "memory effects" of the semi-crystalline systems. 5. Morphology studies using microscopy have revealed the fiber-glass distribution and orientation in the bulk of the material and at the interface. Under the optimized LVW, OVW and H-P welding conditions, some of the glass fibers were found to orient perpendicular or at an angle to the weld plane, and they were also found to be crossing the interface. 6. These local reinforcement effects were found to be very repeatable for the butt joint welded from similar (both halves are nylon 6 or nylon 66, and nylon 66/6 copoly-mer) and dissimilar (nylon 66 with nylon 6) plastics. 7. At present the optimized weld performance for high temperature resistance (46 and HTRN) nylons dissimilar butt joints is not yet achieved due to the large difference in the melt temperature and solubility of the base materials. 8. The presented and discussed optimized weld performance data for commercially available polyamides (nylons) will allow designers to recommend LVW, OVW or H-P technology in plastic product development for welding applications and welded components manufacturing.
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