The Quickstep Process involves a unique fluid-filled, balanced pressure, heated floating mould technology for the curing, partial curing and joining of composite materials. It works by rapidly applying heat to the laminate which is trapped between a free floating rigid (or semi-rigid) mould that floats in a Heat Transfer Fluid (HTF) . The mould and laminate are separated from the circulating HTF by a flexible membrane or bladder. The temperature and pressure of the HTF behind the mould and flexible membrane stay the same. The Quickstep Process uses balanced pressure, combined with vibration within the HTF and vacuum on the laminate, to remove the air and then compact and heat the laminate to cure the part.
A flexible membrane beneath the mould is bonded into a pressure chamber creating the lower half of a 'clam-shell' like mould set. A second flexible membrane is bonded to a separate pressure chamber creating the upper half of the clam-shell. These HTF filled pressure chambers are clamped together during processing. This permits the laminate to be compressed while the mould is not subject to any distortion or stress as it is floating in a balanced pressure/force environment within the HTF.
The use of fluid to control temperature offers several advantages, including:
- Up to 25 times the heat transfer rate of gas systems like autoclave and circulating air ovens, resulting in shorter cycle times
- Improved control of part temperature, with fewer hot or cold spots on the mould
- Rapid decrease in prepreg resin viscosity, resulting in improved fiber wetting and laminate consolidation without high pressures
- The ability to modulate temperature quickly, permitting more accurate injection temperatures or repeatable resin advancement in multi-step cure cycles or in melding of complex components
- Reduced exotherm risk as liquid carries away the heat of reaction more efficiently than air or nitrogen
The Quickstep Process can use thermoset and certain thermoplastic prepregs as well as wet resin/dry fiber to produce superior composite parts. Demonstrations to date have shown equivalent and in many instances superior performance to autoclave, vacuum and atmospheric curing methods in terms of strength, stiffness, surface finish and appearance whilst achieving aerospace grade void contents of less than 2%.
The Quickstep Process achieves this superior performance on larger parts with significantly quicker cycle times at far lower pressures of 1 to 4 psi and lower labor costs than alternative autoclave production systems. Despite the superior performance characteristics, the Quickstep Process is competitive on cost with generic production methodologies like vacuum bag and liquid infusion techniques.