Composites
Fill time goes with the square of flow length. Halving the flow path saves three quarters of the infusion, and no amount of vacuum does that.
— min
To reach the stated flow length
One-dimensional saturated flow with constant permeability and viscosity — a real infusion has a compacting preform, a viscosity rising as the resin cures, and flow media that short-circuit the path entirely. A negative working-life margin means the resin gels before the part fills, which is a scrapped laminate rather than a slow one.
VARTM Resin Infusion Flow & Fill Time Calculator — free, with the formula and a worked example, at Textile School.