Vacuum Casting Clones CYBOT Prototypes!

Vacuum casting resins from MCP achieved the speed of turnaround plus the translucent properties required to build the prototype models of Cybot, the new build-up robot available via a fortnightly magazine.

With a brief to design an easy to assemble but stylish casing which would accommodate Cybot's electronics, Bristol based Amalgam, initially vacuum cast a selection of first generation models of their designs from hand built masters. After the injection moulders had refined the final design, an SLA model was produced from the Pro E CAD file and used as a pattern for the 30 or so vacuum cast prototypes. These were used for pre-launch PR and market research whilst the metal tooling was being produced.

Amalgam's Prototyping Manager, Mike Harvey, explains, "By using vacuum casting to produce the prototypes, we were able to offer the client the speed of turnaround they wanted and something which for all intents and purposes had the looks and functionality of the production item. The beauty of vacuum casting is that once you have a silicone mould of the final part design, you can produce prototypes in a variety of colours and in materials with a variety of properties. We changed the colour of Cybot's final casing four or five times."

MCP's Bob Bennett continues, "There is only so much you can do with CAD before you really have to start making functional parts for evaluation by your target audience." Focus group trials revealed that Cybot had a tendency to topple over due to the weight of its rubber front bumper - a factor not recognised from the initial CAD design. The bumper design was therefore modified and recast using a lighter "ABS" fender with a smaller "rubber" bump strip.

Prototypes of Cybot's body shell, chassis and battery box were cast in MCP SG95, a clear PU resin which replicates the properties of ABS, has a shore hardness of 82D and can be easily pigmented to produce a variety of translucent colours. The bump strips and wheels were cast in MCP 8145, a rubber like PU resin with high tear strength, good elongation properties and a shore hardness of 45A.

Simulating production thermoplastics, glass and rubber, MCP's Vacuum Casting Resins offer a wide range of properties including UV stability, high impact and temperature resistance. MCP's Vacuum Casting Process is used world-wide for prototyping products as diverse as ventilation grills for the Porsche Boxter and Hozelock garden sprinklers. Amalgam has recently used the technology to develop parts for the Dyson Washing Machine and for other hi-tech clients in the marine, geological and aerospace industries. Following the production of a silicone tool, castings are available in a matter of hours - cost effective, finished prototypes can be ready in days and can be evaluated and modified quickly prior to the commissioning of hard tooling.