Cti is embarking on a three-year programme to determine the extent to which the widespread application of Rapid Prototyping in the casting supply chain is a realistic and viable proposition. In particular, Cti will be seeking to determine why, in contrast to the claims made for the various technologies, their penetration in the casting sector is minimal.
Thus far, Cti has never been motivated to use RP because the organisation has always been able to satisfy the most exacting market requirements by means of fast prototyping techniques based on high speed, precision-machining of patterns â permanent or disposable â or by the direct milling of sand moulds. âFirst and foremost, prototype castings have to meet the procurement standards specified,â? asserts Dr Mike Ashton, Chief Executive of Cti. âCustomers are less concerned about how the casting is made than whether it is delivered on time and conforms to the dimensional tolerances, surface finish and structural integrity agreed at the outset. Unless RP can predictably and consistently achieve compliance with procurement criteria, neither the castings sector nor Cti would risk moving away from proven, highly refined and progressively improving techniques which have to be used anyway for castings larger than the limited scale of RP. Achieving failure quickly achieves nothing!â?
The research programme will determine precisely the attributes of various types of RP models such as the predictability, accuracy and repeatability of dimensions. Any variation over time, or distortion of RP models, will also be assessed. Dr. Ashton advises: âIt is important to appreciate that this initial exercise actually has nothing to do with castings manufacture per se. Rather surprisingly, we need to start at first principles to characterise each of the RP systems, since assured data of relevance to casting producers, and more particularly their customers, is seemingly not available, least of all from the technology providersâ?.
The project aims to develop and optimise the procedures by which “fit-for-purpose” RP models can be converted to castings “right first time”. Since Cti already produces prototype castings by a range of fast manufacturing techniques, it has the skills and competencies to realise the potential that may be latent in RP systems and to benchmark their capability against industry norms.
