Rotoform - University of Cambridge, Student Design Project

Rotoform uses an innovative rotational moulding machine to produce hollow fibreboard products from a sawdust mixture. Rotational moulding is widely used in plastic manufacturing, with the ability to form thin hollow products allowing lightweight and novel designs. The team has adapted this technology, using an original machine to maximise spinning speeds.

Combining this capability with the use of sawdust allows Rotoform to produce a similar range of fantastic products but using eco-friendly fibreboard materials Using sawdust is part of what makes Rotoform unique. Sawdust is a waste material – 0.4 million tonnes are produced and disposed of every year. Rotoform takes this sawdust and enables the production of eco-friendly products. Achieving the rotational speeds necessary to use the viscous sawdust mixtures was the most significant challenge the team had to overcome. Traditional rotational moulding machines reach rotational speeds of 60 rpm. Rotoform has designed a more rigid machine, which employs powerful motors allowing stable, high speed rotation.

Development of the optimal mixture required lengthy testing, but the ideal ratios of fibres, PVA and water were finally found. This allowed us to minimise drying times and maximise the strength of the fibreboard. A multitude of shaped products can be formed: lampshades, lunchboxes, fruit bowls, stationery pots, etc. The ability to change the inner surface of the mould gives Rotoform a unique selling point. Additionally fibreboard is easily machined and coated, giving the opportunity for post-forming shaping and finishing methods that would be impossible with existing rotationally moulded polymer components.

The use of waste material combined with the ability to form unique, monocoque fibreboard structures enables Rotoform to produce exciting premium products which would be difficult to manufacture in any other way.

Team: Ashkan Ahmadi, Bradley Bull, Jade Evans, Malko Sordo-de Cock.

More information: www.ifm.eng.cam.ac.uk/education/met/a/design/desig…