Designing a pump impeller that performs well is a challenge. The fluids being pumped are often multi-component and the flow velocities and volumes are high. Current analytical tools will give a rough estimate of pump performance, but actual performance is only determined experimentally. Consequently, achieving optimum performance is an iterative process: create a design, build the impeller, test its performance, tweak the design, and repeat the process until an optimum design is reached.
In practice, however, optimizing performance in this manner has been prohibitively expensive. Tooling costs, especially for large impellers like those that Tech Cast manufacturers, can be very high and lead times long. The tools often require cores, either soluble or ceramic, to create the internal flowpaths, requiring that two tools be built. It simply isn’t practical to repetitively modify or rebuild tooling to evaluate design changes. As a result, pump manufacturers only iterate until they achieve acceptable performance. They can’t afford either the time or cost required for the extra iterations to achieve optimum performance.