A superthermal conductive mandrel technology developed by Acrolab Ltd., Windsor, Ontario, permits the curing of filament-wound pipe and tube sections by uniformly heating a rotating mandrel using an Ambrell induction heating power supply. Induction heating provides clean, precise, even heat.

Trademarked as Isomandrel, the design consists of a process internal to the mandrel that enhances its thermal conductivity and thermal reactivity. The process permits heat to be applied in a localized concentration that is then rapidly and homogeneously redistributed over the mandrel’s working surface.

When coupled with induction heating, the technology permits the mandrel and filament winding to continue rotating while being heated to an optimum controlled temperature to effect cure. This heating occurs while the assembly is still rotating in the winding machine or on a rotating fixture within the manufacturing cell.

Acrolab, working with McClean Anderson Inc., Schofield, Wis., and Ameritherm, an Ambrell company in Scottsville, N.Y., constructed the curing cell at McClean's laboratory. The induction-heated Isomandrel station cured a number of 48" long pipe sections wound with glass and carbon-fiber epoxy prepregs. They were wound on a 3" OD Isomandrel.

At the end of the winding cycle, the sections were cured successfully on the Isomandrel using an Ambrell induction heating power supply and coil assembly while the mandrel and winding were still mounted and rotating at a reduced 10 rpm.

By providing high thermal energy uniformly over the mandrel surface outward through the filament winding, the cure was completed in a shorter time with less energy while providing a uniform cure and resin-rich inner diameter.

Ameritherm and McClean Anderson are developing a software/hardware integrated station to provide the controlled power and recipe requirements to integrate with Acrolab’s mandrel technology.