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Thermwood

Azimut Switch to Core Infusion Technology

30 September 2004

In order to consolidate its technological leadership in the luxury motor cruiser market, Azimut is switching from hand lamination to DIAB Core Infusion Technology.

It is believed that Azimut is the first major serial producer of luxury motor yachts to implement infusion on a full production basis. The decision to adopt infusion moulding was taken in order to achieve further improvements in quality, cut build times, reduce weight and provide a better working environment for Azimut personnel. DIAB Core Infusion was chosen following a thorough evaluation of other composite manufacturing processes including SCRIMP, SPRINT and RTM Light.

After 18 months of production trials that included test mouldings for the Azimut 42, 50, 55, 62 and 68, the company is now using the technology to produce the new Azimut 40 that features a fully cored hull. The company is progressively introducing this closed moulding technology for the hulls, decks and superstructures of its entire range.

DIAB Core Infusion Technology brings together all the benefits of sandwich composites such as lightweight and high strength with the processing, performance and health and safety advantages of closed moulding.

The process also allows faster flow rates and as a result enables the production of very large components, such as complete hulls and decks, in a single shot while substantially reducing lay-up times. It also enables a marked reduction in the number of resin inlet lines. With the DIAB system the specially grooved core not only enhances the structural performance of the composite component, allowing high fibre volume fractions to be achieved but also acts as the resin transfer medium. By eliminating the requirement for sacrificial distribution mats or nets the cost of consumables and waste is significantly reduced.

DIAB Core Infusion Technology is based on using an integral part of the sandwich composite – the core – as the transfer medium. This is achieved by machining the core surface to produce a series of carefully positioned grooves to facilitate resin distribution. As a result the need for a sacrificial distribution net or mat is completely eliminated, as is the requirement for peel ply and release film.

The first stage of the process is to apply the gel coat in a conventional way, followed by a skin coat. The skin coat is a relatively thin layer of surface mats that are applied and then cured in order to enhance the surface finish. Next dry structural reinforcements for the outer skin are positioned in mould.

Then the pre-cut and shaped DIAB Infusion Core (which is supplied to Azimut in the form of ready to use kits) is placed into the mould and the inner skin dry reinforcements are laid up.

The next stage is to install the primary and secondary resin feeder lines followed by the vacuum line. Finally the vacuum bag is installed and sealed along the edge of the mould flange. The vacuum is then applied and the resin inlet valve is opened to allow the infusion process to begin.

Compared to the previous technology employed by Azimut, the company expects to achieve significant reductions in fabrication times. For example, time savings of up to 45% are expected for the production of the hull for the Azimut 40.

Azimut was one of the first major production boat builders to realize that there would be significant benefits in using sandwich composites for the hulls, decks and superstructures of its range of motor cruisers. A reduction in weight provided greater speed, longer range, less engine power and better fuel economy.