Vacuum Cast Impellers
The vacuum casting process puts Aurora ahead of the pack when considering sourcing for brass and bronze impellers. Through the use of the Vacuum Cast Process, along with superior quality and service, Aurora continues to increase its share of the available open and enclosed shrouded impeller market.
Tooling required for the vacuum process consists of a steel vacuum die and permanent core equipment of either the straight blade or back stripping francis blade design. Aurora’s policy for their vacuum die is a one-time only cost to the customer with all maintenance and replacement, when necessary, the responsibility of Aurora Metals.
Design Data and General Information
Advantages of vacuum casting process for impeller production.
- Smooth internal waterways increase pump efficiency.
- Consistent waterway tolerances.
- Minimum machine stock on machining areas. Through the use of the steel die, diameters of wear rings, eye hubs, and driving hubs typically require the removal of 0.030" of material to get to finished size.
- Shroud thickness cast to size requiring no machining.
- Reduced balancing time due to even distribution of material and lack of voids.
- Consistent dimensional repeatability to maximize the use of C.N.C. machining and minimize machining to finished specifications.
TOLERANCES:
- ±.010 to ±.015 on dimensions over 1".
- Ability to maintain tolerances are always effected by die contours and sections.
ALLOYS:
- Silicon Brass - C.D.A. Ref. No. 875 and 876. For use in fresh water applications to mildly brackish applications.
- Aluminum Bronze - C.D.A. Ref. No. 953. For use in harsher environments.
- Nickel Aluminum Bronze - C.D.A. Ref. No. 958. For use in extreme environments ranging from polluted water to salt water.