Model looks are irresistible

Mobile phone mock-ups that not only look like final products, but to some extent even work like them, do not cost vastly more to make than crude block representations. With sales of consumer electronic products dependent on whether look and feel is better than that of competitors - and little product lifecycle time to put things right if they are not - semi-working prototypes are highly desirable for business success. At a recent open day organised by Arrk Product Development Group, project co-ordinator Dennis Bromage unveiled the four grades of rapid prototype the company is able to offer, as illustrated by block models of various stages of mobile phone conceptualisation for a major mobile phone manufacturer. Grade C was a solid block CNC machined out of ABS, with no graphics, no finish and no functionality. Grade B was finished and painted, but without graphics, "As it would appear in switched-off mode", Bromage explains, "it's machined out of ABS as separate components, painted and assembled. The screen is a piece of clear acrylic." Grade A was much more realistic, with applied finishes and chrome effects, and screen printed graphics. Made out of machined ABS parts as well, it also included a weight placed in the back to mimic the presence of batteries. "This is more traditional model making than rapid prototyping," states Bromage, "but taking advantage of modern technology." Grade A+, however, had a real working screen, powered through a phone connector and charger. The screen displays were simulated, but all the types of interaction between user and phone could be scrolled through. "The company used it for its evaluation process, photography and pre-launch publicity," he says. "Big companies generally order 10 or 15 different, finished concepts." With the cost for producing a basic Grade C model around £1,500, with £2,500 the price tag for a fully finished version, it is possible to see why a large company would choose to go for maximum realism, whatever the price, if it enabled it to choose the most saleable concept. For special surfaces, Arrk has a factory in Taiwan that specialises in a technique whereby a film of graphic is placed on a liquid surface and an object lifted through it to be coated in surface that can be wood looking, elaborately patterned or rubbery to the touch. For low-volume production in aluminium, it offers a rubber plaster moulding service. It also goes back to basics when necessary: one particularly complex plastic part for a new range of Flymo mowers was entirely made by CNC machining of ABS. "It's a very cost effective way of producing large parts," Bromage explains. * Arrk will exhibit at the forthcoming TCT show, held at the Ricoh Arena in Coventry on 26-27 September. Pointers * Rapid prototypes can be made with a very high degree of realism, including working parts and semi working displays, if that helps concept evaluation * Optical parts can be rapid prototyped to a standard that equals, or even exceeds, production parts * Aluminium cast parts can be made in production quantities running into thousands