Breaking the budget barrier

Researchers from Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO) have helped in creating a technique that will enable manufacturers to take advantage of advanced polymer composite technology.

Researchers from the Commonwealth Scientific and Industrial Research Organisation (CSIRO) have helped to create Quickstep, a technique that will enable aircraft; boat and car manufacturers take advantage of advanced polymer composite technology.

Advanced polymer composites are extremely strong and light – around 10 times the strength to weight ratio of most metals. These are highly desirable qualities, but until now have been out of reach of most manufacturers, according to CSIRO researcher, Dr Jonathan Hodgkin.

‘Stealth fighter aircraft and very expensive racing cars are made out of these materials,’ said Dr Hodgkin. ‘But the problem with this technology has been that these materials are expensive and time consuming to manufacture, requiring high temperatures in a high pressure apparatus for up to 16 hrs for each part.’

Dr Hodgkin said that the Quickstep process is a fast fabrication method for making very high quality (to aerospace standard) composite products without using an autoclave.

The technique is said to take advantage of the thermal conductivity of fluids such as water to reduce the production time from 24 hours to about 1-hour for aerospace standard epoxy resins with even shorter production times for AAA grade automotive and marine composites. In addition the cost of the apparatus required is low compared to conventional equipment.

The process was invented and patented by Neil Graham of Perth, Western Australia to meet a need to make aerospace parts in volume and quickly without the prohibitive costs associated with autoclave ovens and tooling.

‘Quickstep uses a unique, fluid filled, balanced pressure, floating mould technique, combined with vibration through the fluids to produce advanced fibre and glass reinforced composite components,’ said Graham. ‘The process has superior performance to autoclave, vacuum and atmospheric curing methods in terms of strength, stiffness and appearance.’

Quickstep achieves this superior performance on larger parts with faster cycle times, at far lower pressures of one to four psi compared to autoclaves which operate at 60 to 200 psi and at lower labour costs than alternative aerospace grade production systems.

Graham said that the surrounding fluid system means that the mould and the part being fabricated are supported by fluid and are not subjected to high pressure.

‘Consequently, the mould doesn’t need to be of heavy construction. In addition, sandwich structures with honeycomb or foam cores are made feasible.’

The CSIRO researchers have tested a number of different polymer-fibre systems, including epoxy/carbon fibre and vinyl ester/fibre glass. In each case, the resulting composites were said to have high fibre levels, often over 70 percent, with little porosity.

CSIRO has undertaken trials on the Quickstep process since early 1998. They are now working with Quickstep Technologies to develop the process. A high temperature oil based plant is due for completion in late April 2001 to supplement the water based pilot plant which has been demonstrating the process since 1994.

In addition to working with two aerospace companies, Quickstep Technologies and CSIRO will invite members of the automotive and marine industries to participate in the development of the process to meet their specific needs.