RENSHAPE FIRES UP NEW 'DRAGON' WHEELCHAIR
30 November 2004 - Huntsman Advanced Materials

The Dragon Mobility project is the creation of the Dan Everard Partnership based in Cambridge, UK, who specialise in developing products to improve mobility and lifestyle for disabled people.The wheelchair can operate in or outside, and is suitable for people of any age and up to a weight of 75kg.

Design team leader Dan Everard decided on using RenCast epoxy resin based mould making and RenPIM polyurethane part production materials after consultations with technicians at RenShape Solutions technical support facility in Duxford Cambridge. The materials were chosen for their toughness, high quality surface finish, dimensional accuracy, and in the case of the parts, their good resistance to environmental factors such as water.

The rear castor of the wheelchair was made, first by milling a pattern from aluminium. RenCast CW 47/ Ren® HY 33 was poured against this to make a mould. The castor was then produced in the mould by casting RenPIM 4597/98/99 polyurethane system under low pressure around a steel insert. The RenPIM shot size was 0.8kg.

The RenPIM 4597/98/99 fast curing, three component polyurethane system was also chosen to make the buffers fitted to the rear of the wheelchair. For these chassis buffers a dual impression mould was made from a wooden pattern using silicone rubber.

The buffer was cast from a blend of RenPIM 4597/98/99 to achieve a Shore hardness of 50 and coloured to match RAL7005. This material was chosen because of its flexibility facilitating easy release of the cast components and the durability for repeated castings.

'We had very specific design requirements for the Dragon wheelchair,' explained Marcin Szala, General Manager of the Everard Partnership, 'and after our discussions with RenShape Solutions and their enthusiasm for the project,
we knew their materials perfectly matched our needs.'

'All the components for the Dragon had to be tough enough to withstand 40,000 hours of working life. We were working to a tight product development schedule in order to launch the wheelchair at the Independent Living Exhibition in London at the end of September 2004, which we achieved. Overall, the complete design, testing and production cycle for the parts using RenShape technology took less than two months.'

RenCast CW47/HY33 is a heat resistant casting system formulated for making vacuum forming tools, and for use generally to mould polymeric materials such as thermosets, thermoplastics, composites and polyurethanes.

The RenPIM 4597/98/99 Variable Shore A system is one of a series of polyurethane products design as alternatives to thermoplastic materials for making prototype and short run production parts. They are processed using simple, low cost silicone or epoxy moulds, and are ready to be de-moulded in just a few minutes.

More News:
  • For November 2004
  • From Huntsman Advanced Materials
  • For General