In a government-funded project, IDEC set about achieving these efficiency objectives by exploring the capabilities of RTM (resin transfer moulding) technology. This task focused on the testing of a new composite material and its moulding process for the manufacture of a curved aircraft wing.
With the support of advanced prototyping service provider, Wehl & Partner, IDEC overcame a challenging requirement to replace aluminium in a tooling application involving electric current. Specifically, a preform tool had to be produced in a high-temperature and high-pressure resistant material.
Using its Stratasys F900 Production System, acquired through Spanish distributor Pixel Sistemas, Wehl & Partner selected non-conductive ULTEM 1010 resin to manufacture a large-scale preform tool. The material’s chemical and heat resistance enabled it to withstand temperatures exceeding 150°C, as well as high pressures. In addition, the lead time to produce the preform tool was reduced from four weeks to 60 hours.
According to Diego Calderón, structural analysis manager at IDEC, these attributes simplified the preform production process and delivered efficiency savings: “Not only did we slash the production lead-time on the preform tool, but we expedited the whole composite moulding process. In fact, with ULTEM 1010 resin, we reduced the composite heating stage from one hour to only 10 minutes by flowing the electrical current directly through composite fabrics. This would simply not have been possible without Stratasys FDM additive manufacturing.”
IDEC’s particular constraint in producing the aircraft wing centred on the preform tool itself. Designed to facilitate the composite lay-up process into the mould at a later stage and accelerate the curing process, such preform tools are typically made of aluminium or epoxy resin. The composite fibre is laid up on top of the preform and the tool is subsequently heated to take the shape of the mould.
In this instance, the challenge was that instead of heating the preform tool, the unusual application required the composite material itself to be heated using an electric current sent through the composite fibre. Consequently, highly conductive metals like aluminium were inappropriate and would prevent the current from passing through the fabric in an effective manner.
According to Calderón, standard epoxy materials available inside the company were neither resistant nor stable enough to withstand temperatures exceeding 140°C.
For IDEC, its use of ULTEM 1010 resin resulted in a preform tool with optimised mechanical properties that has enabled the company to utilise it as part of the RTM process. The preform is so solid that the team can use it for at least 25 cycles, something simply not possible with epoxy or other additive manufacturing technologies, says the company.