An impeller is the rotating component of a pump. It transfers the energy from the motor to the fluid and accelerates the fluid to build up pressure. In contrast to an open impeller, a closed impeller additionally has a front shroud attached to it.
Because of the unique geometry of closed pump impellers, the only way to produce these components to date has been to use casting technologies. However, with these technologies there are risks of small internal and surface defects, fair-but-limited surface quality, and slight geometrical inaccuracies. These issues not only affect the overall performance of the part but also determine how much post-processes – like surface treatment and balancing – are necessary.