Calculated internal stress distributions in melt-spun fibers

Although melt spinning is a basic process in the synthetic fiber industry, theoretical understanding of heat transfer and stress development in a melt-spun fiber is limited. In this work, the finite-element method is first applied to the melt-spinning process to determine radial and axial temperature distributions in a solidfying fiber. A thermal stress analysis is then made, again by the finite-element method. Calculated stresses are found to reach maximum values shortly after the fiber solidifies. Because material properties are reduced at these elevated temperatures, this is a location of potential mechanical failure. Anisotropy due to drawing may add to this problem. Analysis of the effects of spinning parameters shows that ambient air temperature is the most critical variable in controlling the internal stresses. Mass flow rate and take-up speed have smaller effects.