For her graduation project, mechanical engineer Ilse ten Bruggencate designed of the Dutch Saxion University of Applied Sciences and tested a safety shoe made of recycled waste material.

A safety shoe has to meet a lot of standards, but the most important one is that especially the toe cap has to be incredibly strong, in case something heavy falls on your feet. Current toe caps are generally made in developing countries of thermosetting composite, a labour-intensive and dangerous job, because of the produced fumes.

Ten Bruggencate’s project was part of a larger project that focuses on the recycling of thermoplastic composites. This type of fibre reinforced composite materials are used for things like airplane hulls or Formula 1 cars. As opposed to thermosetting composites, the thermoplastic kind can be reshaped by heating the material. The project looks for ways to reuse this material in everyday object, such as crates, child seats, and safety shoes.

In the production of thermoplastic composites, a lot of waste material is generated, up to 40 per cent of the material. Ten Bruggencate used this production waste to design a rock-hard toe cap, which can be used in safety shoes.

For her research, she had to take apart existing safety shoes and test the toe caps to see how they react to impact and compression forces. The next step was to make a mould for the new toe caps. The material itself, however, was the most important, as even the direction of the fibres influences the strength of the toe cap.

The final design of the toe cap meets the necessary standards. Its production process could be automated, which means the recycled material toe caps could be made locally in a cleaner process than its current counterpart.

Photo: Saxion