CIMP Software Status: SPIRAL

SPIRAL-C (6/93): fits spiral-flow data by combining simplex method with finite-difference simulation of unsteady, non-isothermal flow in spiral cavity of rectangular cross-section (with width >> half-gap thickness) subject to imposed experimental pressure trace at inlet (under or near sprue); generates values for either 4-constant (n, A, Ta, b), 5-constant (n, tau*, B, Tb, beta) or 7-constant (n, tau*, D1, D2, D3, A1, Ã 2) viscosity models; in addition to fitting the spiral-flow lengths, has option to also fit downstream pressure traces (thereby exploiting more information from each run); the 4-constant model can also be augmented with an effective no-flow temperature (Tcryst), for handling semi-crystalline materials; when running the 5-constant or 7-constant viscosity model, execution time can be reduced by an order of magnitude by invoking a local power-law approximation
SPIRAL-G (6/93): extension of SPIRAL-C to include variable-density effects, including handling of shrinkage which arises after melt front stops; very computationally intensive