Drain pipes ease out crinkled hose

Just as rapid prototyping can be used to manufacture things difficult or impossible to produce by conventional techniques, there are products, easy to make by established processes, which are hard to rapid prototype.

Drain pipes ease out crinkled hose Problem: One example is flexible, semi-rigid hoses whose undercuts protrude substantially into the longitudinal axis. Commercially, such products are made by blow moulding, but rapid prototyping them in more than single numbers requires a silicone mould made from the rapid prototyped former. The outside part of the mould can be peeled off the former. Extracting the inside, however, represents a problem, both when the silicone mould is made, and when it is re-used after making castings. Solution: Such a problem was presented to IMI Rapid Prototyping in the form of a hose with 20mm-wide undercuts for a major truck manufacturer. The solution, according to managing director Craig Vickers, came in the form of a length of plastic drainpipe. This was inserted down the centre of the initial rapid prototyped hose former when the mould elements were made, and when the subsequent test hoses were cast. All that was necessary was the withdrawal of the pipe after each operation. The silicone inner then consisted of a relatively thin tubular section which could be collapsed and withdrawn. Application: Any situation involving the low-batch-number manufacture of complicated pipes. Drainpipe is much cheaper and more readily available than soluble core materials. TS