Abstract: An improved process and apparatus for production of synthetic multifilamentary yarns having uniform quality. The method comprises extruding a molten synthetic polymer downwardly through a spinneret, advancing the extruded filaments downwardly through a substantially stationary column of heated air, and subsequently advancing the filaments downwardly through a quenching zone wherein they are in contact with cooling air introduced into the path of the filaments under controlled conditions of air velocity and direction of flow.

Abstract: It has been suggested that synthetic multifilamentary yarns can be produced by melt-spinning a polyamide or polyester polymer under conditions of substantially simultaneous spinning and drawing wherein prior to said drawing the filaments of the fiber are lubricated with a spin finish by surface contact with a lube roll surface of not less than about 90 RMS. However, in commercial operation of the process at high throughput rates of 50 pounds per hour or greater through the spinneret, serious problems have been encountered due to "flicking" or momentary slackness of one or more filaments from the main yarn bundle above the lube roll, which flicking results in production of yarn of relatively poor quality. It has now been found that the occurrence of said flicking of the filaments can be greatly reduced by applying the spin finish from a convergence guide having a yarn-lubricating surface of not less than about 10 RMS and means for distributing a film of lubricant over said surface.

Abstract: An improved process and apparatus for production of synthetic multifilamentary yarns having uniform quality. The method comprises extruding a molten synthetic polymer downwardly through a spinneret, advancing the extruded filaments downwardly through a substantially stationary column of heated air, and subsequently advancing the filaments downwardly through a quenching zone wherein they are in contact with cooling air introduced into the path of the filaments under controlled conditions of air velocity and direction of flow.