Abstract: In order to spin the high quality PLA filament, the melt spinning method was applied and the chip drying process was optimized. The effect of spinning parameters, including spinning temperature, spinning speed, stretching ratio and stretching temperature, on the qualities of PLA filament (viscosity average molecular weight,orientation and mechanical property) were also researched. The results indicate that: the PLA chip should be dried in two stages. First stage, the temperature should climb up to 60-65℃, for 3-4h, in order to pre-crystallize, second stage, increased drying temperature up to100℃ for 15h. At last, the chip moisture content was lower than 0.005%. The optimum spinning parameters were as follows: 195℃ spinning temperature, 1000m/min spinning speed, 3 stretching ratio and T1/T2/T3=72℃/80℃/82℃stretching temperature.

Key words: PLA filament, melt-spinning, chip drying, stretching speed, stretching