Brass and bronze caster J. Walter Miller Co. recently completed a transition in production — from manual green sand squeeze molding to fully automated molding machines — with the addition of ESI's QuikCAST solidification software. The switch has reduced the number of iterations required to reconfigure patterns, reduced porosity in finished castings, and explored opportunities for yield improvement.
"We selected QuikCAST because it has the most comprehensive capabilities for simulating brass and bronze alloys," said quality engineer at J. Walter Miller Co. Dan Rudolph. "QuikCAST is a very powerful simulation tool."
The foundry was producing non-leaded pump components, including impellers. Due to the heavy and thin sections of the castings, the configuration was not possible on a newly-added DISA Match 130. The impeller castings exhibited shrink porosity and voids in the hub when machined at the customer's facility. The riser at the hub area also required redesign.
J. Walter Miller Co. turned to the simulation program to determine the cause of the defect. Design changes were applied to the CAD model of the casting and input into QuikCAST for evaluation. After the model was finished, the original problem was evident.
Changes modeled in QuikCAST were applied to the impeller during the next production run. The customer noticed a dramatic reduction of scrap in the machining process, which contributed to large cost savings for both the customer and J. Walter Miller Co.
"The problem would have taken about 12 weeks and $6,000 in pattern changes, plus countless hours of machine time to solve using conventional trial and error methods," added Rudolph. "With QuikCAST, we can easily solve similar problems in two weeks and produce a good pattern the first time. We have used simulation on about 20 parts to date and the simulation results are similar to what we see in the shop."