At high sea without a captain – fast production of the autonomous sailboat Avalon with RAKU-TOOL® WB-0750 from RAMPF Tooling

Picture an autonomous sailboat that can reach any predetermined destination independently: this is what the engineering students from the Swiss Federal Institute of Technology (ETH) Zürich, Switzerland and the various sponsors made possible. The specialists from RAMPF Tooling have also contributed to this innovation.

Altogether three parts were produced for the autonomous sailboat: mast, keel and rudder.

Cutting and inserting of prepregs.

Build up of vacuum bag.

Every year the Swiss Federal Institute of Technology (ETH) offers a focus project during the last term of the bachelor engineering degree course. During the project a product has to be developed by a team from idea to finish. The personal fascination with sailing was only one of the reasons to develop and build an autonomous, un-manned sailboat. Amongst other sponsors, RAMPF Tooling was involved in the project. The specialist for model and tool building materials helped the students from the ETH to transform their innovative idea into reality.
Working board material RAKU-TOOL® WB-0750 was used to make prepreg lay-up molds for the production of the Avalon. Altogether three parts were produced for the autonomous sailboat: mast, keel and rudder.

The production of the prepreg lay-up molds was done through direct tooling. With the direct tooling process there is no need to produce a master model since the mold for low temperature prepreg applications is machined directly from CAD data. This is a very fast and economic way of production.
As a first step the strength calculations and operational conditions had to be predefined. These then determined the geometries of the parts and the corresponding cal-culations were simulated and performed on the computer by the students.
Based on these calculations the parts could be constructed. First, the students bonded the board material RAKU-TOOL WB-0750 with epoxy adhesive RAKU-TOOL EP-2304/EH-2934. Then the cavities were machined and the surfaces sealed. After insertion of the carbon fiber prepregs the peel ply and bleeder were placed. The vacuum bag was then built up. The vacuum bag allows for the vacuum pressure build-up to compact the layers and to collect the excess reaction resin in the bleeder which is pressed out during the liquid phase of the cure cycle in order to achieve maximum fiber volume contents. Afterwards all was cured under vacuum and pressure at 80°C for 16 hours in the autoclave.

Advantages of the board material RAKU-TOOL WB-0750 at a glance:
» Service temperature for low temperature epoxy prepregs, up to 70-75°C
» Minimal finishing work through very fine and homogeneous surface
» Very easy to machine
» Good dimensional stability

Avalon Segelboot